0000000000496407

AUTHOR

Arto Valkonen

Tetraiodoethynyl resorcinarene cavitands as multivalent halogen bond donors

The first examples of iodoethynyl resorcinarene cavitands as rigid 3D halogen bond (XB) donor molecules are presented. These concave macrocycles form strong, RXB = 0.78–0.83, halogen bonds with dioxane oxygen, pyridine nitrogen and a bromide anion in tetraproropyl ammonium bromide resulting in deep cavity cavitand structures.

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Recognition of N-Alkyl- and N-Aryl-Acetamides by N-Alkyl Ammonium Resorcinarene Chlorides

N-alkyl ammonium resorcinarene chlorides are stabilized by an intricate array of intra- and intermolecular hydrogen bonds that leads to cavitand-like structures. Depending on the upper-rim substituents, self-inclusion was observed in solution and in the solid state. The self-inclusion can be disrupted at higher temperatures, whereas in the presence of small guests the self-included dimers spontaneously reorganize to 1:1 host-guest complexes. These host compounds show an interesting ability to bind a series of N-alkyl acetamide guests through intermolecular hydrogen bonds involving the carbonyl oxygen (C=O) atoms and the amide (NH) groups of the guests, the chloride anions (Cl(-)) and ammoni…

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Uranyl ion complexes with aminoalcoholbis(phenolate) [O,N,O,O′] donor ligands

Abstract The reaction between uranyl nitrate hexahydrate and phenolic ligand precursor N,N-bis(2-hydroxy-3,5-dimethylbenzyl)-2-aminoethanol (H3L1) in acetonitrile without base affords the dinuclear uranyl complex [(UO2)2(H2L1)2(NO3)2] (1); in the presence of base, the mononuclear complex [UO2(H2L1)2] · 2H2O (2) is formed. Ligand N,N-bis(2-hydroxy-5-t-butyl-3-methylbenzyl)-2-aminoethanol (H3L2) affords a uranyl complex of formula [UO2(H2L2)2] · 2CH3CN (3); ligand N,N-bis(2-hydroxy-3,5-dimethylbenzyl)-3-amino-1-propanol (H3L3) affords a uranyl complex of formula [UO2(H2L3)2] (4); whilst ligand N,N-bis(2-hydroxy-5-t-butyl-3-methylbenzyl)-3-amino-1-propanol (H3L4), used as the hydrochloride, af…

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Crystal structure of [tris(4,4-bipyridine)]diium bis(1,1,3,3-tetracyano-2-ethoxypropenide) trihydrate

In the title hydrated salt, which was obtained from the hydro­thermal reaction between between potassium 1,1,3,3-tetra­cyano-2-eth­oxy­propenide and 4,4′-bi­pyridine in the presence of iron(II) sulfate hepta­hydrate, the ionic components are linked into a three-dimensional network by C—H⋯N hydrogen bonds.

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Pentafluorophenyl salicylamine receptors in anion–π interaction studies

A crystal structure analysis confirms the appropriateness of pentafluorophenyl salicylamine (1a) as a π-acceptor for anion–π interactions. Crystals of 1a·HCl show that the OH-group fixes the anion in a η2-type binding motif above the electron-deficient arene. Attempts to find some relevance for this weak intermolecular force in solution failed. Stronger CH–, NH– and OH–anion interactions are dominant over the weak anion–π interactions. Due to the hydrogen bonding, the non-fluorinated receptor exhibits the highest binding constants within this series.

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Cover Picture: Achieving Strong Positive Cooperativity through Activating Weak Non‐Covalent Interactions (Angew. Chem. Int. Ed. 3/2018)

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Selective recognition of aromatic hydrocarbons by endo-functionalized molecular tubes via C/N-H⋅⋅⋅π interactions

Abstract Molecular recognition of aromatic hydrocarbons by four endo -functionalized molecular tubes has been studied by 1 H NMR spectroscopy, computational methods, and single crystal X-ray crystallography. The binding selectivity is rationalized by invoking shape complementarity and dipole alignment. The non-covalent interactions are proved to predominantly be C/N-H⋅⋅⋅ π interactions.

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Diastereoselective Synthesis of Spiro[pyrazolone-4,3′-tetrahydrothiophenes] via a Sulfa-Michael/Aldol Domino Reaction

Synthesis : journal of synthetic organic chemistry 48(23), 4091-4098(2016). doi:10.1055/s-0035-1562473

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Stacking of Sterically Congested Trifluoromethylated Aromatics in their Crystals – The Role of Weak F···π or F···F Contacts

European journal of organic chemistry : EurJOC 2020(38), 6073-6077 (2020). doi:10.1002/ejoc.202001008

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Synthesis of silacyclopent-2-en-4-ols via intramolecular [2 + 2] photocycloaddition of benzoyl(allyl)silanes

Organosilicon compounds are versatile units with a wide range of uses from medicinal chemistry to the field of organic electronics. An unprecedented method for the synthesis of novel diaryl-substituted silacyclopentenols via blue-light promoted intramolecular [2 + 2] photocycloaddition of acyl silanes is herein disclosed. Additionally, the present findings demonstrate the influence of the olefin substituents in controlling the regioselectivity of the intramolecular Paterno–Buchi reaction, providing silacycles different from previously reported ones. The high degree of functionalization of these compounds makes them attractive precursors to other synthetically challenging silacyclopentanes.

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Piperazine bridged resorcinarene cages.

The one-pot Mannich condensation of resorcinarenes with piperazine and an excess of formaldehyde under high dilution conditions results in a helical cage, namely, a covalently linked dimer of two resorcinarenes connected via four piperazine bridges in yields ranging from 20 to 40%. The compounds were analyzed by NMR spectroscopy, ESI mass spectrometry, and single crystal X-ray diffraction. The helical cages can encapsulate small guest molecules by adapting the cavity volume by changing the helical pitch according to the guest size.

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Weak Intermolecular Anion–π Interactions in Pentafluorobenzyl-Substituted Ammonium Betaines

A series of ammonium–carboxylate and ammonium–sulfonate betaines was synthesized and studied by single-crystal X-ray diffraction analysis to investigate the weak intermolecular interactions as well as the intramolecular interactions in the solid state. None of the expected intramolecular anion–π interactions could be observed, probably because of the steric demands and the reduced nucleophilicity of the anionic part of the betaines. Nevertheless, a weak intermolecular anion–π interaction between the anionic part of the betaine and the pentafluorophenyl unit is present in the structure of 5a.

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(E)-7-(Pyren-1-yl)hept-6-enoic acid

The title compound, C23H20O2, is a precursor of a pyrene-based supramolecular element for non-covalent attachment to a carbon nanotube. The asymmetric unit contains three independent molecules. The carboxylic acid group in each of these molecules serves as an intermolecular hydrogen-bond donor and acceptor, generating the commonly observed double O—H...O hydrogen-bond motif in an eight-membered ring. Weaker C—H...O, π–π [centroid–centroid distance = 3.968 (4) Å] and C—H...π interactions are also found in the crystal structure.

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A conformationally adaptive macrocycle : conformational complexity and host–guest chemistry of zorb[4]arene

Large amplitude conformational change is one of the features of biomolecular recognition and is also the basis for allosteric effects and signal transduction in functional biological systems. However, synthetic receptors with controllable conformational changes are rare. In this article, we present a thorough study on the host–guest chemistry of a conformationally adaptive macrocycle, namely per-O-ethoxyzorb[4]arene (ZB4). Similar to per-O-ethoxyoxatub[4]arene, ZB4 is capable of accommodating a wide range of organic cations. However, ZB4 does not show large amplitude conformational responses to the electronic substituents on the guests. Instead of a linear free-energy relationship, ZB4 foll…

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N-Alkyl ammonium resorcinarene salts: multivalent halogen-bonded deep-cavity cavitands

N-Cyclohexyl ammonium resorcinarene halides, stabilized by an intricate array of hydrogen bonds in a cavitand-like assembly, form multivalent halogen-bonded deep-cavity cavitands with perfluoroiodobenzenes. As observed from the macromolar to infinite concentration range through crystal growth and single crystal X-ray analyses, four 1,4-diiodotetrafluorobenzenes form moderate halogen bonds with the bromides of the N-cyclohexyl ammonium resorcinarene bromides leading to a deep-cavity cavitand-like structure. In this assembly, the N-cyclohexyl ammonium resorcinarene bromide also acts as a guest and sits in the upper cavity of the assembly interacting with the 1,4-diiodotetrafluorobenzene throu…

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N2,N2.N6,N6-Tetrakis(perfluorobenzoyl)-2,6-diaminopyridine

The title compound, C³³H³F²⁰N³O⁴, is a highly fluorinated organic imide that was isolated as an unexpected product from the reaction of 2,6-diaminopyridine with 2,3,4,5,6-pentafluorobenzoyl chloride in a 1:2 molar ratio. The molecule is located on a twofold axis and one of its symmetry-independent 2,3,4,5,6-pentafluorobenzoyl groups is disordered over two sets of sites, the occupancy of the major component being 0.773 (3). In the major component, the dihedral angle between the perfluorophenyl groups is 63.64 (10)°, and these groups form dihedral angles of 67.14 (7) and 21.1 (2)° with the pyridine core. Short intermolecular C-HO and C-H...N contacts are found in the crystal structure. peerRe…

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Two (E)-2-({[4-(dialkylamino)phenyl]imino}methyl)-4-nitrophenols.

The slow evaporation of analytical NMR samples resulted in the formation of crystals of (E)-2-({[4-(dimethylamino)phenyl]imino}methyl)-4-nitrophenol, C15H15N3O3, (I), and (E)-2-({[4-(diethylamino)phenyl]imino}methyl)-4-nitrophenol, C17H19N3O3, (II). Despite the small structural difference between these twoN-salicylideneaniline derivatives, they show different space groups and diverse molecular packing. The molecules of both compounds are close to being planar due to an intramolecular O—H...N hydrogen bond. The 4-alkylamino-substituted benzene ring is inclined at an angle of 13.44 (19)° in (I) and 2.57 (8)° in (II) with respect to the 4-nitro-substituted phenol ring. Only very weak intermole…

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Titelbild: Achieving Strong Positive Cooperativity through Activating Weak Non‐Covalent Interactions (Angew. Chem. 3/2018)

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1H, 13C NMR spectral and single crystal structural studies of toxaphene congeners. Quantum chemical calculations for preferred conformers of 2,5-endo,6-exo,8,9,9,10,10-octachloro-2-bornene and their DFT/GIAO 13C chemical shifts

Abstract The 1H and 13C NMR chemical shifts for six toxaphene congeners: 2-exo,3-endo,6-exo,8,9,10-hexachloro- (1), 2-exo,3-endo,5-exo,9,9,10,10-heptachloro- (2), 2-exo,3-endo,6-exo,8,9,10,10-heptachloro- (3), 2-exo,3-endo,5-exo,6-endo,8,9,10-heptachloro- (4), 2-exo,3-endo,5-exo,6-endo,8,9,9,10-octachlorobornane (5) and 2,5-endo,6-exo,8,9,9,10,10-octachloro-2-bornene (6) are reported. Their chemical shift assignments have been obtained by means of Pulsed Field Gradient (PFG) Double Quantum Filtered (DQF) 1H,1H correlation spectroscopy (COSY), PFG 1H,13C Heteronuclear Multiple Quantum Coherence (HMQC) and PFG 1H,13C Heteronuclear Multiple Bond Correlation (HMBC) experiments. A single crystal…

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endo-Functionalized molecular tubes : selective encapsulation of neutral molecules in non-polar media

Four endo-functionalized molecular tubes with urea/thiourea groups in the deep cavities have been synthesized, and their binding ability to neutral molecules studied. Very high binding affinity and selectivity have been achieved, which are rationalized by invoking the shape and electrostatic complementarity and dipole alignment.

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Crystal Structures and Cytotoxicity of ent-Kaurane-Type Diterpenoids from Two Aspilia Species

A phytochemical investigation of the roots of Aspilia pluriseta led to the isolation of ent-kaurane-type diterpenoids and additional phytochemicals (1⁻23). The structures of the isolated compounds were elucidated based on Nuclear Magnetic Resonance (NMR) spectroscopic and mass spectrometric analyses. The absolute configurations of seven of the ent-kaurane-type diterpenoids (3⁻6, 6b, 7 and 8) were determined by single crystal X-ray diffraction studies. Eleven of the compounds were also isolated from the roots and the aerial parts of Aspilia mossambicensis. The literature NMR assignments for compounds 1 and 5 were revised. In a cytotoxicity assay, 12α-methoxy-ent-kaur-9(11),1…

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The pentafluorophenyl group as π-acceptor for anions: a case study

Chemical science 6(1), 354-359 (2015). doi:10.1039/C4SC02762K

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Synthesis of 6,12-Disubstituted Methanodibenzo[b,f][1,5]dioxocins : Pyrrolidine Catalyzed Self-Condensation of 2′-Hydroxyacetophenones

The preparation of unprecedented 6,12-disubstituted methanodibenzo[b,f][1,5]dioxocins from pyrrolidine catalyzed self-condensation of 2′-hydroxyacetophenones is herein described. This method provides easy access to this highly bridged complex core, resulting in construction of two C–O and two C–C bonds, a methylene bridge and two quaternary centers in a single step. The intricate methanodibenzo[b,f][1,5]dioxocin compounds were obtained in up to moderate yields after optimization of the reaction conditions concerning solvent, reaction times and the use of additives. Several halide substituted methanodibenzo[b,f][1,5]dioxocins could be prepared from correspondent 2′-hydroxyacetophenones.

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Bifunctional coordination polymers as efficient catalysts for carbon dioxide conversion

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Self-assembly properties of bile acid derivatives of L-cysteine, L-valine and L-serine alkyl esters

Comprehensive self-assembly studies for nine bile acid amides of amino acid esters are reported. The number of the hydroxyl groups attached to the steroidal skeleton and the character of the amino acid ester moiety were used as variables when examining the self-assembly properties of the compounds. Two of the compounds were shown to undergo self-assembly leading to organogelation. In addition, preliminary self-assembly studies in aqueous mixtures of polar organic solvents were conducted. Microscopic methods (optical microscopy and scanning electron microscopy) were utilised in order to gain a deeper insight into the self-assembled structures. Furthermore, single-crystal X-ray structures for…

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cis,cis,cis-(Acetato-k2O,O´)bis[1,2-bis- (diphenylphosphanyl)ethane-k2P,P´]- ruthenium(II) 0.75-trifluoromethanesulfonate 0.25-chloride

In the title RuII carboxylate compound, [Ru(C₂H₃O₂)(C₂₆H₂₄P₂)₂](CF₃O₃S)₀.₇₅Cl₀.₂₅, the distorted tris-bidentate octahedral stereochemistry about the RuII atom in the complex cation comprises four P-atom donors from two 1,2-bis(diphenylphosphanyl)ethane ligands [Ru-P = 2.2881 (13)-2.3791 (13) Å] and two O-atom donors from the acetate ligand [Ru-O = 2.191 (3) and 2.202 (3) Å]. The disordered counter-anions are located on the same site in the structure in a 3:1 ratio, the expanded formula comprising four complex cations, three trifluoromethanesulfonate anions and one chloride anion, with two such formula units in the unit cell. peerReviewed

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Alternative Motifs for Halogen Bonding

The halogen-bonding interaction is one of the rising stars in supramolecular chemistry. Although other weak interactions and their influence on the structure and chemistry of various molecules, complexes and materials have been investigated thoroughly, the field of halogen bonding is still quite unexplored and its impact on chemistry in general is yet to be fully revealed. In principle, every Y–X bond (Y = electron-withdrawing atom or moiety, X = halogen atom) can act as a halogen-bond donor when the halogen is polarized enough by Y. Perfluorohalocarbons are iconic halogen-bond donor molecules in which Y is a perfluorinated aryl or alkyl moiety and X is either iodine or bromine. In this art…

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Single-Crystal X-ray Diffraction and Solution Studies of Anion-π Interactions inN-(Pentafluorobenzyl)pyridinium Salts

A solid-state structural study on anion–π interaction in various N-(pentafluorobenzyl)pyridinium salts accompanied by NMR spectroscopic investigations is presented. The crystal structures of 1a–1d reveal different kinds of contacts with anions, including anion–π interactions. In particular, the solid-state structure of 1b-I3 shows distinct evidence of anion–π interactions. Attempts to study anion–π interactions in solution were not successful, but their presence in solution could not be ruled out.

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Efficient stabilisation of a dihydrogenphosphate tetramer and a dihydrogenpyrophosphate dimer by a cyclic pseudopeptide containing 1,4-disubstituted 1,2,3-triazole moieties

A cyclic pseudooctapeptide 2 is described containing 1,4-disubstituted 1,2,3-triazole moieties. This compound features eight converging hydrogen bond donors along the ring, namely four amide NH and four triazole CH groups, which enable 2 to engage in interactions with anions. While fully deprotonated sulfate anions exhibit only moderate affinity for 2, protonated anions such as dihydrogenpyrophosphate and dihydrogenphosphate anions are strongly bound. Complexation of the phosphate-derived anions involves sandwiching of a dihydrogenpyrophosphate dimer or a dihydrogenphosphate tetramer between two pseudopeptide rings. X-ray crystallography provided structural information, while 1H NMR spectro…

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From attraction to repulsion : anion–π interactions between bromide and fluorinated phenyl groups

Anion–π interactions in crystals of fluorobenzyl ammonium salts depend on the degree of fluorination at the aromatics.

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Growth, single crystal investigation, hirshfeld surface analysis, DFT studies, molecular docking, physico-chemical characterization and, in vitro, antioxidant activity of a novel hybrid complex

Abstract Interaction of the diphosphoric acid (H4P2O7) and organic ligand (3.4-dimethylaniline) with transition metal ions, cobalt (II) chloride leads to the formation of novel stable Co(II)-diphosphate cluster with empirical formula (C8H12N)2[Co(H2P2O7)2(H2O)2].2H2O. The structure of the synthesized material was confirmed by single crystal XRD at 120 ​K. The crystal was plate and crystallized in the triclinic P 1 ¯ space group with a ​= ​7.5340(4) A, b ​= ​7.5445(4) A, c ​= ​13.6896(8) A, α ​= ​84.215(5)°, β ​= ​76.038(5)°, γ ​= ​74.284(5)°, V ​= ​726.38(7) A3 and Z ​= ​1. Full-matrix least-squares refinement converged at R ​= ​0.035 and Rw ​= ​0.088 for 3636 independent observed reflectio…

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Synthesis of silacyclopent-2-en-4-ols via intramolecular [2 + 2] photocycloaddition of benzoyl(allyl)silanes

Organosilicon compounds are versatile units with a wide range of uses from medicinal chemistry to the field of organic electronics. An unprecedented method for the synthesis of novel diaryl-substituted silacyclopentenols via blue-light promoted intramolecular [2 + 2] photocycloaddition of acyl silanes is herein disclosed. Additionally, the present findings demonstrate the influence of the olefin substituents in controlling the regioselectivity of the intramolecular Paternò–Büchi reaction, providing silacycles different from previously reported ones. The high degree of functionalization of these compounds makes them attractive precursors to other synthetically challenging silacyclopentanes. …

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Asymmetric Synthesis of Spiro β-Lactamsviaa Squaramide- Catalyzed Sulfa-Michael Addition/Desymmetrization Protocol

An efficient asymmetric synthesis of spirocyclohexenone β-lactams bearing three contiguous stereocenters has been achieved in moderate to good yields and high stereoselectivities. The protocol involves the combination of a squaramide-catalyzed sulfa-Michael addition under desymmetrization via a dynamic kinetic resolution of racemic 2,5-cyclohexadienones.

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The influence of CH bond polarization on the self-association of 2-acylaminopyrimidines by NH/CH···O/N interactions: XRD, NMR, DFT, and AIM study

The single crystal structures of two 2-acylaminopyrimidines, where alkyl groups in acyl moiety are iso-propyl (1) and dichloromethyl (2), were solved by X-ray diffraction method. The strength of intermolecular hydrogen bonding interactions depends on the C–H bond polarization increased by exchanging two methyl groups by chlorine atoms in the adjacent substituent. The computational methods provide an additional insight into the intermolecular interactions and are utilized in explaining the differences in the observed crystal structures. The experimental and computational data together explain the differences in the formed aggregates and revealed that these simple substitutions cause crucial …

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Connecting Electron-Deficient and Electron-Rich Aromatics to Support Intermolecular Interactions in Crystals

Five compounds bearing electron-deficient pentafluorophenyl as well as electron-rich (salicylate or indole) aromatic moieties connected by amide or ester linkages were investigated by X-ray diffraction. In the crystals, various interactions (π–π, lone pair–π) between the different aromatic units are important structure controlling factors in addition to the stronger inter- or intramolecular hydrogen bonds induced by the amide and ester moieties. The hydrogen bonding leads to polymeric and macrocyclic assembly of the molecular building blocks.

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Oxoanion binding to a cyclic pseudopeptide containing 1,4-disubstituted 1,2,3-triazole moieties

A macrocyclic pseudopeptide 3 is described featuring three amide groups and three 1,4-disubstituted 1,2,3-triazole units along the ring. This pseudopeptide was designed such that the amide NH groups and the triazole CH groups converge toward the cavity, thus creating an environment well suited for anion recognition. Conformational studies in solution combined with X-ray crystallography confirmed this preorganisation. Solubility of 3 restricted binding studies to organic media such as 5 vol% DMSO/acetone or DMSO/water mixtures with a water content up to 5 vol%. These binding studies demonstrated that 3 binds to a variety of inorganic anions in DMSO/acetone including chloride, nitrate, sulfat…

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1H, 13C, 15N NMR, ESI mass spectral and single crystal X-ray structural characterization of three spiro[pyrrolidine-2,3′-oxindoles]

Abstract Three spiro[pyrrolidine-2,3′-oxindoles], 1,1′,2,2′,5′,6′,7′,7′a-octahydro-2-oxo-1′-phenyl-spiro[3H-indole-3,3′-[3H]-pyrrolizine]-2′-carboxylic acid methyl ester (1), 1,1′,2,2′,5′,6′,7′,7′a-octahydro-2-oxo-1′-nitro-2′-phenyl-spiro[3H-indole-3, 3′-[3H]-pyrrolizine] (2) and 1,1′,2,2′,5′,6′,7′,7′a-octahydro-2-oxo-1′-nitro-2′-(4″-chlorophenyl)-spiro[3H-indole-3,3′-[3H]-pyrrolizine] (3) have been synthesized and their 1H, 13C and 15N spectra assigned. The chemical shift assignments are based on Pulsed Field Gradient (PFG) Double Quantum Filter (DQF) 1H, 1H correlation spectroscopy (COSY), PFG 1H, 13C Heteronuclear Multiple Quantum Coherence (HMQC) and PFG 1H,X (X = 13C and 15N) Heteronuc…

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N-(2-Benzoyl-4-chlorophenyl)-4-chlorobenzenesulfonamide

The title compound, C19H13Cl2NO3S, is an N-arylsulfonyl derivative of 2-amino-5-chlorobenzophenone. The compound is biologically active and shows potential to be utilized as an inhibitor of CCR2 and CCR9 receptor functions. In the crystal structure, there is an intramolecular N—H...O hydrogen bond between the amide and carbonyl groups. The benzoyl and 4-chlorophenyl groups form intramolecular and intermolecular face-to-face contacts, with a dihedral angle of 10.6 (1)° between their mean planes in both cases, and centroid–centroid separations of 4.00 (1) and 4.25 (1) Å for the intra- and intermolecular interactions, respectively.

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2,5-Dimethyl-4′-nitrobiphenyl

The title compound, C14H13NO2, is a non-planar biphenyl derivative, in which the dihedral angle between the benzene rings is 62.65 (5) °.

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Entrapment of a linear water pentamer into a uranyl-salophen dimer in the solid state

In the solid state, uranyl-salophen complex 1, decorated with bipyridyl sidearms, self-assembles from moist acetonitrile into dimeric species displaying a confined water pentamer, as observed by X-ray diffraction on single crystals. The linear water cluster is incarcerated within the dimeric cavity by coordination to the Lewis acidic uranyl centres and by a network of hydrogen bonds established with the pyridinic nitrogen atoms on the sidearms.

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Retraction notice to “trans-Tetrakis(pyridine)dichloroiron(II) as catalyst for Suzuki cross-coupling in ethanol and water” [Tetrahedron Lett. 49 (2008) 6679]

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Solid state anion–π interactions involving polyhalides

The stabilization of polyhalides in the solid state with the support of electron-deficient pentafluorophenyl groups is described. Furthermore, a synthetic approach towards the sensitive tetraiodide dianion is described and ESI mass spectrometric evidence for its presence in solution is reported.

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Novel lithocholaphanes: Syntheses, NMR, MS, and molecular modeling studies

Abstract Novel head-to-head lithocholaphanes 6 and 11 have been synthesized via precursors 1 – 5 and 7 – 10 with overall good yields, and characterized by 1 H, 13 C, and 15 N NMR spectroscopy, ESI-TOF mass spectrometry, thermal analysis, and molecular modeling. In addition, the binding abilities of 6 and 11 towards alkali metal cations have been investigated via competitive complexation studies using equimolar mixtures of Li + , Na + , K + , and Rb + -cations, and cholaphanes 6 and 11 . The formation of cation–cholaphane adducts was detected by ESI-TOF mass spectrometry. The trends in these comparative binding studies are nicely reproduced theoretically with PM3 energetically optimized stru…

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Selective Recognition of Phenazine by 2,6‐Dibutoxylnaphthalene‐Based Tetralactam Macrocycle

A 2,6‐dibutoxylnaphthalene‐based tetralactam macrocycle was designed and synthesized. This macrocycle shows highly selective recognition to phenazine ‐‐ a well‐known secondary metabolite in bacteria and an emerging disinfection byproduct in drinking water. In contrast, the macrocycle shows no binding to the structurally similar dibenzo‐1,4‐dioxin. It was revealed that hydrogen bonding, π‐π and σ‐π interactions are the major driving forces between phenazine and the new tetralactam macrocycle. A perfect complementarity in electrostatic potential surfaces may explain the high selectivity. In addition, the macrocycle shows fluorescent response to phenazine, demonstrating its potential in fluore…

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Connecting Electron-Deficient and Electron-Rich Aromatics to Support Intermolecular Interactions in Crystals (Eur. J. Org. Chem. 15/2015)

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Enantiomeric Resolution of Asymmetric-Carbon-Free Binuclear Double-Stranded Cobalt(III) Helicates and Their Application as Catalysts in Asymmetric Reactions

A series of double-stranded binuclear helicates [Co2(H1)2]4+, [Co2(H2)2]4+, and [Co2(H3)2]4+, derived from monodeprotonated bis-pyridyl hydrazine-based ligands of H21, H22, and H23 with one, two, and three -CH2 spacers, were obtained. These asymmetric-carbon-free racemic helicates were separated into their ΔΔ and ΛΛ enantiomers. The resolved helicates were examined for the first time as enantioselective catalysts in asymmetric benzoylation and nitroaldol reactions.

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Self-assembly of new cobalt complexes based on [Co(SCN)4], synthesis, empirical, antioxidant activity, and quantum theory investigations

The cobalt (II) complexes have been synthesized from the reaction of the cationic entities (3,4-dimethylaniline (1) and histamine (2)) with metallic salt CoCl2⋅6H2O and thiocyanate ion (SCN−) as a ligand in H2O/ethanolic solution and processing by the evaporation crystal growth method at room temperature to get crystals. The synthesized complex has been fully characterized by single-crystal X-ray diffraction. UV–Visible, FTIR spectroscopy, TGA analysis, and DFT circulations were also performed. The crystal structural analysis reveals that the solid (1) {[Co(SCN)4] (C8H12N)3}·Cl crystallizes in the monoclinic system with the space group P21/n and the solid (2) {[Co(SCN)4](C5H11N3)2}·2Cl crys…

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2-Methyl-4-phenyl-3,4-dihydro­quinazoline

The title compound, C15H14N2, was formed during the lithiation of 2-methylquinazoline with phenyllithium followed by hydrolysis of the intermediate lithium 2-methyl-4-phenyl-4H-quinazolin-3-ide. NMR spectra as well as single-crystal X-ray structural data indicate that the reaction product to have the same structure in chloroform solution as in the crystalline state. The phenyl substituent is twisted out of the plane of the 3,4-dihydroquinazoline ring system by 86.47 (7)°. In the crystal, intermolecular N—H...N interactions connect the molecules into infinite chains.

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Copper(II) complexes with tridentate N2O donor Schiff base isomers: Modulation of molecular and crystalline architectures through supramolecular interactions

Abstract Four copper(II) complexes, [Cu(L1)(μ-Cl)]n (1), [Cu2(L2)2(μ-Cl)2] (2), [Cu(L1)(μ1,5-NCNCN)]n (3) and [Cu(L2)(μ1,5-NCNCN)]n (4), where HL1 = 1-[(2-dimethylamino-ethylimino)-methyl]-naphthalen-2-ol and HL2 = 1-[(2-ethylamino-ethylimino)-methyl]-naphthalen-2-ol, acting as tridentate N2O donor ligands, have been prepared and characterized by elemental analysis, IR and UV–Vis spectroscopy and single crystal X-ray diffraction studies. Complexes 1, 3 and 4 show polymeric chain structures, whereas 2 has a double chloride bridged dimeric structure. The existence of C–H⋯π interactions between the dimeric units of 2 gives rise to a 2D supramolecular network. Complex 3 shows a zipper structure…

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Tautomeric preferences of phthalones and related compounds

Abstract Multinuclear magnetic resonance and IR spectra prove that although 2-(diacylmethyl)pyridines and 2-(diacylmethyl)quinolines are β-diketones, their proton transfer product present in chloroform solution is not ketoenol but enaminone (earlier opinions were contradictory). Quinoline derivatives are less zwitterionic by character than the respective pyridyl congeners. The β-diketone form itself may also be rarely present in the solution. X-ray data show that 2-(2(1H)-pyridinylidene)-1H-indene-1,3(2H)-dione, i.e., enaminone tautomer of 2-(pyridin-2-yl)-2H-indene-1,3-dione, is also the only form present in crystal. Ab initio calculations show that the enaminone is usually more stable tha…

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Selective recognition of aromatic hydrocarbons by endo-functionalized molecular tubes via C/N-H⋅⋅⋅π interactions

Molecular recognition of aromatic hydrocarbons by four endo-functionalized molecular tubes has been studied by 1H NMR spectroscopy, computational methods, and single crystal X-ray crystallography. The binding selectivity is rationalized by invoking shape complementarity and dipole alignment. The non-covalent interactions are proved to predominantly be C/N-H⋅⋅⋅π interactions. peerReviewed

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Synthesis and characterization of lithocholic acid derived dipyrromethanes: precursors for pyrrole-steroidal macrocycles

Abstract Three steroidal dipyrromethanes, 3,3,24,24-tetrakis(pyrrol-2-yl)-5β-cholane 1 , 3,3-bis(pyrrol-2-yl)-5β-cholan-24-oic acid 2 , and methyl 3,3-bis(pyrrol-2-yl)-5β-cholan-24-oate 3 , have been prepared from 3α-hydroxy-5β-cholan-24-oic acid (lithocholic acid) 4 in good overall yields. The structures of 1 – 3 have been fully characterized by 1 H, 13 C, PFG DQF 1 H– 1 H COSY, 1 H– 1 H ROESY, 13 C DEPT-135, PFG 1 H– 13 C HMQC, PFG 1 H– 13 C HMBC, and PFG 1 H– 15 N HMBC NMR spectra. Their molecular weights and compositions have been determined by ESI-TOF and EI mass spectra, and elemental analyses. The energetically optimised geometry and isotropic 13 C NMR chemical shifts of 3,3,24,24-te…

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Entrapment of a linear water pentamer into a uranyl-salophen dimer in the solid state

In the solid state, uranyl-salophen complex 1, decorated with bipyridyl sidearms, self-assembles from moist acetonitrile into dimeric species displaying a confined water pentamer, as observed by X-...

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Discovery of 5-benzyl-3-phenyl-4,5-dihydroisoxazoles and 5-benzyl-3-phenyl-1,4,2-dioxazoles as potent firefly luciferase inhibitors.

Luciferase reporter assays are commonly used in high-throughput screening methods. Here, we report new firefly luciferase (FLuc) inhibitors based on 5-benzyl-3-phenyl-4,5-dihydroisoxazoles and 5-benzyl-3-phenyl-1,4,2-dioxazoles, which showed up as "false positives" in a luciferase reporter gene-based assay for nuclear receptor antagonists. The inhibition was shown to be noncompetitive for both natural enzyme substrates (d-luciferin and ATP) and selective to FLuc and proven to arise from a direct interaction between the enzyme and the inhibitor. Of the 63 evaluated compounds, 28 showed significantly better inhibition potency than the well-known inhibitor resveratrol (IC(50) = 59 nM), with fi…

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Di-, Tri-, and Tetra(pentafluorophenyl) Derivatives for Oligotopic Anion−π Interactions

The present study describes a series of pentafluorobenzyl ammonium salts with two, three, or four C6F5 units in order to investigate simultaneous interactions of several perfluorinated arenes with anions in the crystalline state. Most of the structures show multiple anion-π contacts. However, only 6·2HI reveals an effective encapsulation of the iodide ion by the aromatic units. For comparison, the structure of 4b is investigated because it offers two π-systems with inverse charge distribution to a bromide anion. Only the electron-deficient π-system of the pentafluorophenyl group interacts with the anion.

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Water-Soluble Cuprizone Derivative: Synthesis, Characterization, and in Vitro Studies

The cuprizone mouse model is one of the most accepted model systems for the investigation of oligodendrocyte degeneration, a process critically involved in the pathogenesis of diseases such as multiple sclerosis or schizophrenia. In order to substitute the in vivo experiments by in vitro approaches, the amine derivative BiMPi is introduced as a water-soluble alternative to cuprizone. Regarding superoxide dismutase activity, toxicity for oligodendrocytes, and disturbance of mitochondrial membrane potential, BiMPi shows similar in vitro effects as is observed in vivo for cuprizone. peerReviewed

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6-Amino-2-(pivaloylamino)pyridinium benzoate

In the crystal structure of the title salt, C10H16N3O+·C7H5O2−, the cations and anions are linked to each other via N—H⋯O hydrogen bonds, forming infinite chains running along [010]. The crystal structure also features C—H⋯O and π–π stacking inter­actions, which assemble the chains into supra­molecular layers parallel to (100). The π–π stacking inter­actions are observed between the pyridine rings of inversion-related cations with a centroid–centroid distance of 3.867 (2) Å. Financial support from the National Science Centre in Kraków (grant No. NCN204 356840) is gratefully acknowledged. Academy Professor Kari Rissanen (Academy of Finland grant Nos. 122350, 140718, 265328 and 263256) and th…

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Halogen and Hydrogen Bonded Complexes of 5-Iodouracil

Three derivatives of 5-iodouracil were prepared, and their complexation properties, supplemented by 5-iodouracil under the same conditions, were studied with and without halogen bond acceptors in N,N-dimethylformamide, N,N-diethylformamide, N-methylformamide, formamide, dimethylsulfoxide, and water. The intermolecular halogen and hydrogen bonding interactions observed in the solid state were investigated using single crystal X-ray diffraction and quantum chemical calculations, and the acquired data were contrasted with bonding interactions previously reported for 5-iodouracil in the Cambridge Structural Database. It was found that the polarized iodine atom and the amidic NH functionality ac…

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Microwave assisted synthesis and solid-state characterization of lithocholyl amides of isomeric aminopyridines

Microwave (MW) assisted synthesis and solid state structural characterizations of novel lithocholyl amides of 2-, 3-, and 4-aminopyridine are reported. It is shown that the MW technique is a proper method in the preparation of N-lithocholyl amides of isomeric aminopyridines. It offers many advantages compared to conventional heating. The molecular and crystal structures as well as the polymorphic and hydrated forms of prepared conjugates with their thermodynamic stabilities have been characterized by means of high resolution liquid- and solid-state NMR spectroscopy, single crystal and powder X-ray diffraction, and thermogravimetric analysis. Owing to the many biological functions of bile ac…

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Association of N-(Pyridin-2-yl),N′-substituted Ureas with 2-Amino-1,8-naphthyridines and Benzoates: NMR and Quantum Chemical Studies of the Substituent Effect on Complexation

Association of four N-(pyridin-2-yl),N'-R(1)-ureas (R(1) = ethyl, n-butyl, phenyl, and tert-butyl) with substituted 2-amino-1,8-naphthyridines and benzoates were studied by (1)H NMR spectroscopic titrations and quantum chemical calculations. The benzoates and 2-amino-1,8-naphthyridines were selected as representatives of double and triple hydrogen bonding counterparts, respectively. The classical substituent effect on the association was studied. A prerequisite and a crucial step for the complex formation was the breaking of the intramolecular hydrogen bond in urea derivatives. The QTAIM calculation method was employed to explain the hydrogen bonding within complexes. In the case of benzoat…

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CH-Directed Anion-π Interactions in the Crystals of Pentafluorobenzyl-Substituted Ammonium and Pyridinium Salts

Simple pentafluorobenzyl-substituted ammonium and pyridinium salts with different anions can be easily obtained by treatment of the parent amine or pyridine with the respective pentafluorobenzyl halide. Hexafluorophosphate is introduced as the anion by salt metathesis. In the case of the ammonium salt 4, water co-crystallisation seems to suppress effective anion-pi interactions of bromide with the electron-deficient aromatic system, whereas with salts 5 and 6 such interactions are observed despite the presence of water. However, due to asymmetric hydrogen-bonding interactions with ammonium side chains, the anion of 5 is located close to the rim of the pentafluorophenyl group (eta(1) interac…

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Thiourea Based Tritopic Halogen Bonding Acceptors

Series of thiourea based tritopic receptor molecules were synthesized to be used as building blocks for halogen-bonded assemblies. Here 16 new receptor molecules were synthesized from two different 2,4,6-trialkyl-1,3,5-tris(bromomethyl)benzene starting materials via tris(isothiocyanatomethyl)benzene intermediates. The alkyl substituents in the benzene ring showed to be important for isothiocyanate group formation instead of competing thiocyanate group. The synthesis route allowed us to synthesize the isothiocyanate intermediates and further the receptor molecules without typically used and highly toxic thiophosgene. Synthesized receptor molecules were used to study their halogen bond accept…

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CH-Anion versus anion-π interactions in the crystal and in solution of pentafluorobenzyl phosphonium salts

A series of phosphonium salts with pentafluorobenzyl substituents have been synthesized and were investigated in the crystal as well as in solution. The solid state structures of 1a, 1b and 2d reveal the presence of anion-π as well as CH-anion interactions. The two attractive, yet competitive forces seem to act in concert and a directing effect of the CH interaction on the relative position between anion and π-system is observed. The search for anion-π interactions in solution failed. Only CH-anion interactions proved to be important in solution.

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Entrapment of a linear water pentamer into a uranyl-salophen dimer in the solid state

In the solid state, uranyl-salophen complex 1, decorated with bipyridyl sidearms, self-assembles from moist acetonitrile into dimeric species displaying a confined water pentamer, as observed by X-ray diffraction on single crystals. The linear water cluster is incarcerated within the dimeric cavity by coordination to the Lewis acidic uranyl centres and by a network of hydrogen bonds established with the pyridinic nitrogen atoms on the sidearms.

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CF3: An Electron-Withdrawing Substituent for Aromatic Anion Acceptors? “Side-On” versus “On-Top” Binding of Halides

The ability of multiple CF3 -substituted arenes to act as acceptors for anions is investigated. The results of quantum-chemical calculations show that a high degree of trifluoromethyl substitution at the aromatic ring results in a positive quadrupole moment. However, depending on the polarizability of the anion and on the substitution at the arene, three different modes of interaction, namely Meisenheimer complex, side-on hydrogen bonding, or anion-π interaction, can occur. Experimentally, the side-on as well as a η(2) -type π-complex are observed in the crystal, whereas in solution only side-on binding is found.

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X-Ray crystallographic and computational study on uranyl-salophen complexes bearing nitro groups.

In the solid state, salophen–UO2 complexes bearing one, two, or three NO2 groups lack the pronounced ligand curvature that represents a structural hallmark for this class of compounds. A detailed structural study based on single-crystal X-ray crystallography and computational methods, comprising molecular dynamics, gas-phase Hartree Fock, and DFT calculations, was carried out to investigate the coordination properties of the uranyl cation.

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Synthesis, characterization and antimicrobial activity of palladium(II) complexes with some alkyl derivates of thiosalicylic acids: Crystal structure of the bis(S-benzyl-thiosalicylate)–palladium(II) complex, [Pd(S-bz-thiosal)2]

Abstract S-Alkyl (R = benzyl, methyl, ethyl, propyl and butyl) derivatives of thiosalicylic acid and the corresponding palladium(II) complexes were prepared and their structures were proposed on the basis of infrared, 1H and 13C NMR spectroscopy. The cis geometrical configurations of the isolated complexes were proposed on the basis of an X-ray structural study of the bis(S-benzyl-thiosalicylate)–palladium(II), [Pd(S-bz-thiosal)2] complex. Antimicrobial activity of the tested compounds was evaluated by determining the minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) in relation to 26 species of microorganisms. The tested ligands, with a few exceptions, sho…

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Bile acid–cysteamine conjugates: Structural properties, gelation, and toxicity evaluation

Abstract Design, synthesis, and characterization of six novel bile acid–cysteamine conjugates together with investigation of their structural studies, gelation properties, and preliminary toxicity evaluation, are reported. Solid state properties of selected compounds were studied by means of X-ray diffraction and 13C CPMAS NMR spectroscopy. N-(2-thioethyl)-3α,7α,12α-trihydroxy-5β-cholan-24-amide was shown to exhibit (pseudo)polymorphism, and a single crystal structure of its non-stoichiometric hydrate is reported herein. Cholyl and dehydrocholyl derivatives bearing three functionalities in their steroidal backbone were shown to undergo self-assembly leading to gelation in certain organic so…

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Deoxygenative Divergent Synthesis : En Route to Quinic Acid Chirons

The installation of vicinal mesylate and silyl ether groups in a quinic acid derivative generates a system prone for stereoselective borane-catalyzed hydrosilylation through a siloxonium intermediate. The diversification of the reaction conditions allowed the construction of different defunctionalized fragments foreseen as useful synthetic fragments. The selectivity of the hydrosilylation was rationalized on the basis of deuteration experiments and computational studies. peerReviewed

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N,N-Di-n-octyl-N,N-dimethyl and N,N-di-n-nonyl-N,N-dimethyl ammonium cholates: 13C and 15N CPMAS NMR, powder X-ray diffraction and thermoanalytical characterization

Abstract N,N-Di-n-octyl-N,N-dimethyl cholate (1) and N,N-di-n-nonyl-N,N-dimethyl ammonium cholate (2) have been prepared by crystallization from equimolar mixtures of sodium cholate and quaternary N,N-di-n-alkyl-N,N-dimethyl (n-octyl or n-nonyl) ammonium bromides. The formed crystalline materials have been structurally characterized by 13C and 15N cross polarization magic angle spinning (CPMAS) NMR, powder X-ray diffraction (PXRD) and thermoanalytical (TGA/DTA and DSC) methods and compared with each other. Powder X-ray diffraction patterns of 1 and 2 reveal clear similarities. Combined with the thermoanalytical data of these structures an existence of two hydrated polymorphs (most probably …

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Efficient stabilisation of a dihydrogenphosphate tetramer and a dihydrogenpyrophosphate dimer by a cyclic pseudopeptide containing 1,4-disubstituted 1,2,3-triazole moieties† †In memoriam Fritz Vögtle (1939–2017). ‡ ‡Electronic supplementary information (ESI) available: Synthetic details, NMR spectroscopic and MS spectrometric characterisation of 2, NMR spectroscopic and mass spectrometric binding studies, ITC titrations, and crystal structures. CCDC 1555955–1555958. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7sc02700a Click here for additional data file. Click here for additional data file.

A cyclic pseudooctapeptide binds a dihydrogenpyrophosphate dimer or a cyclic dihydrogenphosphate tetramer by sandwiching these anionic aggregates between two pseudopeptide rings.

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Synthesis, characterization and solid-state photoluminescence studies of six alkoxy phenylene ethynylene dinuclear palladium(II) rods

A rare family of six discrete binuclear [PdCl(PEt3)2] phenylene ethynylene rods with alkoxy side chains (methoxy, ethoxy and heptoxy) have been developed, and their solid-state photoluminescence results have been presented and discussed. The shorter bridging ligands are of the general formula H–CuC– C6H2(R)2–CuC–H, where R = H, OCH3, OC 2H5, and OC7H15, whereas the longer ones are based on H– CuC–C6H4–CuC–C6H2(R)2–CuC–C6H4–CuC–H, where R = OCH3, OC 2H5. These ligands display increasing length in both the main dimension (backbone length) as well as the number of carbons in the side chains (R, alkoxide side chain) that stem from the central phenylene moiety. The X-ray crystal structures of tw…

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Bile acid amidoalcohols: simple organogelators.

Simple bile acid amide synthesis of lithocholic and deoxycholic acids with 2-aminoethanol and 3-aminopropanol are reported. The structural properties of these amides were examined by NMR spectroscopic, ESI-TOF mass spectral, and X-ray crystallographic methods. The gelation properties of these amides in common organic solvents and in three different water solutions were also investigated using Tyndall effect, SEM, TEM, and optical microscopy. 2-Hydroxyethylamides were found to be effective gelators in chlorinated organic solvents and 3-hydroxypropylamides in aromatic solvents. Both derivatives thicken neutral and acidic water solutions.

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An aryl-fused redox-active tetrathiafulvalene with enhanced mixed-valence and radical-cation dimer stabilities.

Molecular recognition of stable organic radicals is a relatively novel, but important structural binding motif in supramolecular chemistry. Here, we report on a redox-switchable veratrole-fused tetrathiafulvalene derivative VTTF which is ideally suited for this purpose and for the incorporation into stimuli-responsive systems. As revealed by electrochemistry, UV/Vis measurements, X-ray analysis, and electrocrystallisation, VTTF can be reversibly oxidised to the corresponding radical-cation or dication which shows optoelectronic and structural propterties similar to tetrathiafulvalene and tetrakis(methylthio)tetrathiafulvalene. However, theoretical calculations, variable temperature EPR, and…

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Achieving Strong Positive Cooperativity through Activating Weak Non-Covalent Interactions

Positive cooperativity achieved through activating weak non-covalent interactions is common in biological assemblies but is rarely observed in synthetic complexes. Two new molecular tubes have been synthesized and the syn isomer binds DABCO-based organic cations with high orientational selectivity. Surprisingly, the ternary complex with two hosts and one guest shows a high cooperativity factor (α=580), which is the highest reported for synthetic systems without involving ion-pairing interactions. The X-ray single-crystal structure revealed that the strong positive cooperativity likely originates from eight C-H⋅⋅⋅O hydrogen bonds between the two head-to-head-arranged syn tube molecules. Thes…

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2-Acylamino- and 2,4-bis(acylamino)pyrimidines as supramolecular synthons analysed by multiple non-covalent interactions. DFT, X-ray diffraction, and NMR spectral studies

Intermolecular interactions of ten 2-acylamino and 2,4-bis(acylamino)pyrimidines (7 of which are previously unknown) have been investigated by X-ray structural, quantum chemical (DFT), and NMR spectral methods. Especially the concentration dependencies of the (1)H NMR chemical shifts and titrations with other molecules capable of multiple hydrogen bonding provided useful information regarding their association via triple or quadruple hydrogen bonding, which is controlled by the conformational preferences of 2-acylamino- and 2,4-bis(acylamino)pyrimidines. On comparison of the properties of 2-acylamino- and 2,4-bis(acylamino)pyrimidines with the corresponding pyridines, an additional nitrogen…

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trans-4-tert-Butyl-1-methylcyclohexanol hemihydrate

The title compound, C11H22O·0.5H2O, is a hemihydrate of trans-4-tert-butyl-1-methyl­cyclo­hexa­nol, containing one water and two organic mol­ecules in the asymmetric unit. Crystals were obtained from an NMR sample by very slow evaporation of the solvent. In the solid state, the title compound forms a double-layered structure with the organic and water mol­ecules connected by O—H⋯O hydrogen bonds.

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RETRACTED: trans-Tetrakis(pyridine)dichloroiron(II) as catalyst for Suzuki cross-coupling in ethanol and water

Aryl bromides can be coupled with phenylboronic acid in moderate to excellent yields using a transtetrakis(pyridine)dichloroiron(II) catalyst. The Suzuki–Miyaura reaction can be carried out under air in ethanol and aqueous ethanol with low catalyst loading. Addition of TBAB dramatically increases the yields in aqueous ethanol or in water. trans-Tetrakis(pyridine)dichloroiron(II) offers an environmental and less expensive method for the synthesis of biaryl compounds. This is the first example of an iron– pyridine catalyst for Suzuki cross-coupling.

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3α-Hydroxy-N-(3-hydroxypropyl)-5β-cholan-24-amide

The title compound, C27H47NO3, is a (3-hydroxypropyl)amide derivative of naturally occurring enantiopure lithocholic acid (3-hydroxy-5-cholan-24-oic acid). The molecule contains four fused rings: three six-membered rings in chair conformations and one five-membered ring in a half-chair form. The two terminal six-membered rings are cis-fused, while other rings are trans-fused. The structure contains an intramolecular O—H O hydrogen bond and a similar hydrogen-bond framework to the corresponding deoxycholic and chenodeoxycholic acid derivatives. Intermolecular O— H O and N—H O interactions are also present in the crystal. This compound seems to have at least two polymorphic forms from a compa…

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Asymmetric Synthesis of Functionalized Tricyclic Chromanes via an Organocatalytic Triple Domino Reaction

A highly stereoselective triple domino reaction for the synthesis of functionalized tricyclic chromane scaffolds has been developed. A secondary amine-catalyzed domino Michael/Michael/aldol condensation reaction between aliphatic aldehydes, nitro-chromenes, and α,β-unsaturated aldehydes leads to the formation of synthetically important tricyclic chromanes bearing four contiguous stereogenic centers including a tetrasubstituted carbon in good yields (20–66%) and excellent stereoselectivities (>20:1 dr and >99% ee).

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Chasing Weak Forces: Hierarchically Assembled Helicates as a Probe for the Evaluation of the Energetics of Weak Interactions.

London dispersion forces are the weakest interactions between molecules. Because of this, their influence on chemical processes is often low, but can definitely not be ignored, and even becomes important in cases of molecules with large contact surfaces. Hierarchically assembled dinuclear titanium(IV) helicates represent a rare example in which the direct observation of London dispersion forces is possible in solution even in the presence of strong cohesive solvent effects. Hereby, the dispersion forces do not unlimitedly support the formation of the dimeric complexes. Although they have some favorable enthalpic contribution to the dimerization of the monomeric complex units, large flexible…

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Structural, Thermoanalytical and Molecular Modeling Studies on N-(3-hydroxypropyl) 3a,12a-Dihydroxy-5b-cholan-24-amide and Its Monohydrates

The synthetic method for preparing N-(3-hydroxypropyl) 3 alpha,12 alpha-dihydroxy-5 beta-cholan-24-amide can lead to formation of at least three different crystal forms - an anhydrous compound and two monohydrates. The structural and thermal properties of these forms have been characterized by 13C-CP/MAS-NMR and IR spectroscopy, thermo- gravimetry, differential scanning calorimetry and by powder and single crystal x-ray crystallography. In addition, theoretical 13C-NMR chemical shift calculations were also performed for the anhydrous compound and for the first monohydrate, starting from single crystal structures and the structures of these species have now been verified. The first monohydra…

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Efficient stabilisation of a dihydrogenphosphate tetramer and a dihydrogenpyrophosphate dimer by a cyclic pseudopeptide containing 1,4-disubstituted 1,2,3-triazole moieties

A cyclic pseudooctapeptide 2 is described containing 1,4-disubstituted 1,2,3-triazole moieties. This compound features eight converging hydrogen bond donors along the ring, namely four amide NH and four triazole CH groups, which enable 2 to engage in interactions with anions. While fully deprotonated sulfate anions exhibit only moderate affinity for 2, protonated anions such as dihydrogenpyrophosphate and dihydrogenphosphate anions are strongly bound. Complexation of the phosphate-derived anions involves sandwiching of a dihydrogenpyrophosphate dimer or a dihydrogenphosphate tetramer between two pseudopeptide rings. X-ray crystallography provided structural information, while 1 H NMR spectr…

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Halogen Bonding between Thiocarbonyl Compounds and 1,2- and 1,4-Diiodotetrafluorobenzenes

The halogen bonding (XB) between 1,2-diiodotetrafluorobenzene (1,2-DITFB) or 1,4-diiodotetrafluorobenzene (1,4-DITFB) and the selection of different thiocarbonyl acceptors was studied by the single-crystal X-ray diffraction method. Diiodotetrafluorobenzenes (DITFBs) were found to form C-I···S halogen-bonded 1:1, 2:1, and 1:2 (donor/acceptor ratio) complexes with thiocarbonyls. Lengths of contacts were found to be clearly shorter than the sum of van der Waals radii of iodine and sulfur as well as the contact angles showed values close to linear, so the XB interactions could be verified. One sulfur atom showed the ability to accept one, two, or four XB interactions, and the acceptor angle can…

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Synthesis and characterization of novel bile-acid – heteroaryl conjugates with N-(2-aminoethyl)amido linker

Abstract Four novel bile acid conjugates N-[2-([2,2′]-bithiophen-5-ylmethyl)aminoethyl]-3α-hydroxy-5β-cholan-24-amide (1), N-[2-([2,2′]-bithiophen-5-ylmethyl)aminoethyl]-3α,7α,12α-trihydroxy-5β-cholan-24-amide (2), N-[2-(1H-pyrrol-2-ylmethyl)aminoethyl]-3α-hydroxy-5β-cholan-24-amide (3), N-[2-(pyridin-2-ylmethyl)aminoethyl]-3α-hydroxy-5β-cholan-24-amide (4) have been synthesized in moderate to good yields, and their structures have been characterized by 1H, 13C, 13C DEPT-135, PFG 1H,13C HMQC, and PFG 1H,13C HMBC NMR spectra. Their molecular weights and elemental compositions have been determined by ESI-TOF mass spectrometry and elemental analyses. Crystal structure of 1 characterized with o…

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Self-Organization of 2-Acylaminopyridines in the Solid State and in Solution

Aggregation of 2-acylaminopyridines and their 6-methyl derivatives in chloroform solution was studied by (1)H, (13)C, and (15)N NMR spectroscopies. The results were compared with (13)C and (15)N CPMAS NMR and IR spectral as well as with X-ray structural data. Intermolecular interactions in solution and in solid state were found to have a similar nature. Relatively strong N(amide)-H···N(pyridine) intermolecular hydrogen bonds enable dimerization to take place. Steric interactions in N-pivaloyl- and N-1-adamantylcarbonyl as well as that caused by the 6-methyl group hinder formation of the dimeric aggregates stabilized by the N(amide)-H···N(pyridine) intermolecular hydrogen bonds. In general, …

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2-exo,5-endo,8,8,10-Pentachlorobornane

The title compound, C(10)H(13)Cl(5), is a polychlorinated monoterpene and a Toxaphene congener. This compound is also the only penta-chlorinated derivative of camphene formed via ionic chlorination. Previously, the title compound was thought to be 2-exo,5-endo,9,9,10-penta-chloro-bornane, but X-ray structural analysis showed it to have a different structure and rather to be 2-exo,5-endo,8,8,10-penta-chloro-bornane. The title compound shows static disorder and almost half the molecule was divided in two partitions with an occupancy ratio of 0.575 (major) to 0.425 (minor). The repulsive close contacts of Cl atoms could possibly be the cause for this disorder.

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N-Benzyl-2,3,4,5,6-pentafluorobenzamide

In the title compound, C14H8F5NO, the dihedral angle between the planes of the pentafluorophenyl and phenyl rings is 18.34 (5)°. An intermolecular N—H...O hydrogen bond between the amide groups connects these molecules to form an infinite chain through the crystal structure. One weak intermolecular C—H...O contact and one π–π interaction [centroid–centroid distance = 3.772 (3) Å] are also involved in crystal structure stabilization between the phenyl rings.

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Synthesis and Structural Characterization of Substituted 2-Phenacylbenzoxazoles

1 H and 13C NMR spectra of eleven 2-phenacylbenzoxazoles (ketimine form) show that their CDCl3-solutions contains also (Z)-2-(benzo[d]oxazol-2-yl)-1-phenylethenols (enolimine form). Intramolecular hydrogen bonding in the latter tautomer was found to be significantly weaker than that one in respective (Z)-2-(2-hydroxy-2-phenylvinyl)pyridines. Integrals of the 1 H NMR signals were used to evaluate the molar ratio of the tautomers. Strong electron-donating substituents were found to stabilize the ketimine tautomer. pKT (negative logarithm of the equilibrium constant, KT = [ketimine]/[enolimine]) was found to be linearly dependent on the Hammett substituent constant σ. The results of the MP2 ab…

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Dihydrooxazine Oxides as Key Intermediates in Organocatalytic Michael Additions of Aldehydes to Nitroalkenes

Pause and play: dihydrooxazine oxides are stable intermediates that are protonated directly, without the intermediacy of the zwitterions, in organocatalytic Michael additions of aldehydes and nitroalkenes (see scheme, R=alkyl). Protonation of these species explains both the role of the acid co-catalyst in these reactions, and the observed stereochemistry when the reaction is conducted with α-alkylnitroalkenes.

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Palladium-catalyzed dehydrogenative β'-functionalization of β-keto esters with indoles at room temperature.

The dehydrogenative β′-functionalization of α-substituted β-keto esters with indoles proceeds with high regioselectivities (C3-selective for the indole partner and β′-selective for the β-keto ester) and good yields under mild palladium catalysis at room temperature with a variety of oxidants. Two possible mechanisms involving either late or early involvement of indole are presented.

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Ti(iv)-amino triphenolate complexes as effective catalysts for sulfoxidation

C 3 -symmetric Ti (IV) amino triphenolate complexes efficiently catalyze, without previous activation and in excellent yields, the oxidation of sulfides at room temperature, using both CHP and the more environment friendly aqueous hydrogen peroxide as terminal oxidants, with catalyst loadings down to 0.01%. The Ti(IV) catalysts and the intermediate Ti(IV)-peroxo complexes have been characterized in solution by 1H NMR and ESI-MS techniques and via density functional studies.

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Perfluoro-1,1′-biphenyl and perfluoronaphthalene and their derivatives as π-acceptors for anions

Addition of anions to perfluorinated 1,1′-biphenyl 1 or naphthalene 2 results in a shift of the 19F NMR signals. However, any specific interaction cannot be assigned to this effect. In order to study the interaction in more detail, the salt derivatives 3 and 4 were prepared and studied by single crystal X-ray diffraction revealing weak anion–π interactions in the solid state.

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Prenylated Flavonoids from the Roots of Tephrosia rhodesica

Five new compounds—rhodimer (1), rhodiflavan A (2), rhodiflavan B (3), rhodiflavan C (4), and rhodacarpin (5)—along with 16 known secondary metabolites, were isolated from the CH2Cl2–CH3OH (1:1) extract of the roots of Tephrosia rhodesica. They were identified by NMR spectroscopic, mass spectrometric, X-ray crystallographic, and ECD spectroscopic analyses. The crude extract and the isolated compounds 2–5, 9, 15, and 21 showed activity (100% at 10 μg and IC50 = 5–15 μM) against the chloroquine-sensitive (3D7) strain of Plasmodium falciparum. peerReviewed

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Halogen-Bonded Co-Crystals of Aromatic N-oxides : Polydentate Acceptors for Halogen and Hydrogen Bonds

The C-ethyl-2-methylresorcinarene (1) forms 1:1 in-cavity complexes with aromatic N,N′-dioxides, only if each of the aromatic rings has an N−O group. The structurally different C-shaped 2,2′-bipyridine N,N′-dioxide (2,2′-BiPyNO) and the linear rod-shaped 4,4′-bipyridine N,N′-dioxide (4,4′-BiPyNO) both form 1:1 in-cavity complexes with the host resorcinarene in C4v crown and C2v conformations, respectively. In the solid state, the host–guest interactions between the 1,3-bis(4-pyridyl)propane N,N′-dioxide (BiPyPNO) and the host 1 stabilize the unfavorable anti-gauche conformation. Contrary to the N,N′-dioxide guests, the mono-N-oxide guest, 4-phenylpyridine N-oxide (4PhPyNO), does not form an…

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Comparative NMR and IR spectral, X-ray structural and theoretical studies of eight 6-arylidenedibenzo[b,e]thiepin-11-one-5,5-dioxides

Abstract Eight 6-arylidenedibenzo[b,e]thiepin-11-one-5,5-dioxides are characterized by NMR and IR spectroscopy. Single crystal X-ray structures for three congeners are reported. In addition, the transmission of substituent effects in conjugated double bond system of 6-arylidenedibenzo[b,e]thiepin-11-one-5,5-dioxide framework has been evaluated by calculating the correlations between selected 13C NMR chemical shifts and IR stretching wave numbers and Hammett constants of the substituents locating in the phenyl ring of the arylidene moiety.

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Comparison of calculated DFT/B3LYP and experimental 13C and 17O NMR chemical shifts, ab initio HF/6-31G* optimised structures, and single crystal X-ray structures of some substituted methyl 5β-cholan-24-oates

Abstract Single crystal X-ray structures (monoclinic space group P2 1 ) for methyl 3-oxo-5β-cholan-24-oate and methyl 3,12-dioxo-5β-cholan-24-oate have been solved and compared with HF/6-31G* optimised structures. In the crystalline packings the side chains are connected with weak OC(sp 3 ) H ⋯ O -type of interactions between C25– H and C24– O –C25 and the keto ends with weak C(sp 3 ) H ⋯ O C-type of interactions between C4– H and O C3. The orientations of the side chains, which steric configurations are of great importance to the biological activity of the molecules, are compared with the experimental structure of methyl 3α-hydroxy-5β-cholan-24-oate. Probable reasons for the observed dif…

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A novel caryophyllene type sesquiterpene lactone from Asparagus falcatus (Linn.); Structure elucidation and anti-angiogenic activity on HUVECs

Abstract In this study the novel caryophyllene type sesquiterpene lactone (aspfalcolide) has been isolated from the leaves of Asparagus falcatus (Linn.) and characterized by IR, 1D NMR, 2D NMR, EI–MS, HR–ESI–MS and X-ray single crystal diffraction analysis. The aspfalcolide crystallizes in the orthorhombic space group P212121 with a = 6.37360(10), b = 7.6890(2), c = 27.3281(6) A, α = β = γ = 90° and Z = 4. One intermolecular O–H⋯O hydrogen bond enforces these natural molecules to form infinite chains through the crystal. Aspfalcolide was screened for its anti-angiogenic activity in human umbilical vein endothelial cells (HUVECs) and the result showed the remarkable inhibitory effect of aspf…

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Molecular aggregation in selected crystalline 1:1 complexes of hydrophobicD- andL-amino acids. IV. TheL-phenylalanine series

The amino acid L-phenylalanine has been cocrystallized with D-2-aminobutyric acid, C(9)H(11)NO(2).C(4)H(9)NO(2), D-norvaline, C(9)H(11)NO(2).C(5)H(11)NO(2), and D-methionine, C(9)H(11)NO(2).C(5)H(11)NO(2)S, with linear side chains, as well as with D-leucine, C(9)H(11)NO(2).C(6)H(13)NO(2), D-isoleucine, C(9)H(11)NO(2).C(6)H(13)NO(2), and D-allo-isoleucine, C(9)H(11)NO(2).C(6)H(13)NO(2), with branched side chains. The structures of these 1:1 complexes fall into two classes based on the observed hydrogen-bonding pattern. From a comparison with other L:D complexes involving hydrophobic amino acids and regular racemates, it is shown that the structure-directing properties of phenylalanine closel…

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Cooperativity of H-bonding and anion–π interaction in the binding of anions with neutral π-acceptors

A rare anion-π complex between bromide and a neutral receptor is reported and related receptor systems are studied with a series of anions. The interaction is observed in the solid state and in solution, and further evidence for it is obtained by a computational study.

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The pentafluorophenyl group as π-acceptor for anions: a case study† †This manuscript is dedicated to Prof. Jean-Marie Lehn on the occasion of his 75th birthday. ‡ ‡Electronic supplementary information (ESI) available. CCDC 967089, 967097, 1005267–1005289. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4sc02762k Click here for additional data file. Click here for additional data file.

A unique structural study investigates the variability of anion–π bonding in the solid state structures of pentafluorophenyl arenes. The hapticity concept is used as tool to describe the structural differences of various anion–π complexes.

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Dual-stimuli pseudorotaxane switches under kinetic control

A series of dumbbell-shaped sec-ammonium salts with bulky (pseudo)stoppers (‘speed bumps’) were tested for their ability to form pseudorotaxanes with a redox-switchable, tetrathiafulvalene (TTF)-decorated [24]crown-8 ether. Depending on the size of the pseudostoppers, fast (less than ten minutes), slow (hours to days) and very slow (no pseudorotaxanes observed) threading has been observed. NMR spectroscopy as well as tandem mass spectrometry indicate the formation of non-threaded face-to-face complexes prior to pseudorotaxanes formation. Both isomers can be distinguished by their substantially different stability in collision-induced dissociation (CID) experiments. Two external stimuli affe…

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(Z)-Ethyl 2-oxo-3-(1,2-dihydroquinolin-2-ylidene)propanoate

Both independent molecules in the asymmetric unit of the tautomeric title compound, C14H13NO3, a synthetic product obtained from 2-lithiomethylquinoline and diethyl oxalate, crystallize in the enaminone form with a Z configuration around the double bond. Intramolecular N—H...O hydrogen bonds occur, generating an S(6) graph-set motif. In the crystal, weak intermolecular C—H...O and π–π stacking interactions [centroid–centroid distances = 3.7020 (14)–3.7429 (13)Å] define a three-dimensional supramolecular network.

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Coordinatively Unsaturated Lanthanide(III) Helicates: Luminescence Sensors for Adenosine Monophosphate in Aqueous Media

Coordinatively unsaturated double-stranded helicates [(H2 L)2 Eu2 (NO3 )2 (H2 O)4 ](NO3 )4 , [(H2 L)2 Tb2 (H2 O)6 ](NO3 )6 , and [(H2 L)2 Tb2 (H2 O)6 ]Cl6 (H2 L=butanedioicacid-1,4-bis[2-(2-pyridinylmethylene)hydrazide]) are easily obtained by self-assembly from the ligand and the corresponding lanthanide(III) salts. The complexes are characterized by X-ray crystallography showing the helical arrangement of the ligands. Co-ligands at the metal ions can be easily substituted by appropriate anions. A specific luminescence response of AMP in presence of ADP, ATP, and other anions is observed. Specificity is assigned to the perfect size match of AMP to bridge the two metal centers and to replac…

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Bis(6-thioxo-1,6-dihydropurinium) tetrachlorozincate(II).

The title salt, (C(5)H(5)N(4)S)(2)[ZnCl(4)], consists of two 6-thioxo-1,6-dihydropurinium (6mpH(2)(+)) cations (A and B) and a tetrachlorozincate anion, which are held together by N-H...Cl and C-H...Cl interactions. There is an anion-pi interaction between one Cl atom of the [ZnCl(4)](-) anion and the pyrimidine ring of the 6mpH(2)(+)(B) cation. Intermolecular pi-pi stacking interactions allow 6mpH(2)(+)(A) cations to form antiparallel pairs. One interesting structural feature is the double N-H...N intermolecular hydrogen bonds between two 6mpH(2)(+)(A) cations. This kind of interaction, mimicking that of natural nucleobases, can be very valuable in designing new therapeutic purine derivati…

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Solid state structural studies of five bile acid derivatives

Five synthetically important bile acid derivatives have been characterized by 13 C CP-MAS, X-ray diffraction (both single crystal and powder), FTIR, and thermoanalytical (DSC and TG) methods. The crystallinity of all these derivatives is high, which can be deducted from the 13 C CP-MAS and powder X-ray diffraction data. Two of the compounds showed polymorphism, and one polymorph was structurally elucidated for both by comparing single crystal and powder X-ray diffraction data.

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NMR and quantum chemical studies on association of 2,6-bis(acylamino)pyridines with selected imides and 2,2′-dipyridylamine

Association constants of 2,6-bis(alkylcarbonylamino)pyridines (alkyl = methyl or ethyl) and their perfluoroalkyl analogues with succin- and maleimide as well as with 2,2′-dipyridylamine (complementary DAD and ADA hydrogen bonding motifs are responsible for formation of the associates) have been determined by NMR titrations and quantum chemical calculations. Interactions of 2,6-bis(alkylcarbonylamino)pyridines with imides differ by character from these of perfluoroalkyl analogues. Such large difference was not observed for the 2,2′-dipyridylamine associates. Since fluorine atoms cause carbonylamino groups to be stronger hydrogen bond donors, perfluorinated species of this type were found to …

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Thermodynamic and electrochemical study of tailor-made crown ethers for redox-switchable (pseudo)rotaxanes

Crown ethers are common building blocks in supramolecular chemistry and are frequently applied as cation sensors or as subunits in synthetic molecular machines. Developing switchable and specifically designed crown ethers enables the implementation of function into molecular assemblies. Seven tailor-made redox-active crown ethers incorporating tetrathiafulvalene (TTF) or naphthalene diimide (NDI) as redox-switchable building blocks are described with regard to their potential to form redox-switchable rotaxanes. A combination of isothermal titration calorimetry and voltammetric techniques reveals correlations between the binding energies and redox-switching properties of the corresponding ps…

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Structural studies of five novel bile acid-4-aminopyridine conjugates

Abstract Synthesis and solid-state structural characterization of five bile acid amides of 4-aminopyridine (4-AP) are reported. Systematic crystallization experiments revealed a number of structural modifications and/or solvate/hydrate systems for these conjugates. Particularly, cholic acid conjugate exhibited five distinct structure modifications, including one anhydrous form, mono- and dihydrates, as well as ethanol and 2-butanol solvates. The obtained crystal forms were examined extensively with various analytical methods, including solid-state NMR, Raman, and IR spectroscopies, powder and single crystal X-ray diffraction methods, thermogravimetry, and differential scanning calorimetry. …

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ChemInform Abstract: Dihydrooxazine Oxides as Key Intermediates in Organocatalytic Michael Additions of Aldehydes to Nitroalkenes.

Pause and play: dihydrooxazine oxides are stable intermediates that are protonated directly, without the intermediacy of the zwitterions, in organocatalytic Michael additions of aldehydes and nitroalkenes (see scheme, R=alkyl). Protonation of these species explains both the role of the acid co-catalyst in these reactions, and the observed stereochemistry when the reaction is conducted with α-alkylnitroalkenes.

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Bile acid–amino acid ester conjugates: gelation, structural properties, and thermoreversible solid to solid phase transition

Design, synthesis, and gelation properties of three novel biocompatible bile acid–L-methionine methyl ester conjugates are presented. Two of the conjugates have been shown to undergo self-assembly leading to organogelation in certain aromatic solvents. The properties of these gels have been investigated by conventional methods typical for molecular gel studies along with 13C CPMAS NMR spectroscopic studies of the native gel. In addition, properties in solid and solution states for all three compounds have been investigated, and single crystal X-ray structures of all compounds determined. Furthermore, powder X-ray diffraction studies have revealed that compound 1 undergoes a dynamic and reve…

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N-Alkyl ammonium resorcinarene salts: multivalent halogen-bonded deep-cavity cavitands

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Halogen-Bonded Mono-, Di-, and Tritopic N-Alkyl-3-iodopyridinium Salts

Halogen bonding interactions of 15 crystalline 3-iodopyridinium systems were investigated. These systems were derived from four N-alkylated 3-iodopyridinium salts prepared in this study. The experimental results in the solid state show that halogen bonding acts as a secondary intermolecular force in these charged systems but sustains the high directionality of interaction in the presence of other intermolecular forces. Halogen bonds donated by polytopic 3-iodopyridinium cations are also sufficient to enclose guest molecules inside the formed supramolecular cavities. The experimental data were supplemented by computational gas-phase and solid-state studies for selected halogen-bonded systems…

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Deprotonation of resorcinarenes by mono- and diamine bases: complexation and intermolecular interactions in the solid state

The deprotonation of resorcinarenes by mono- and dibasic amines, viz. triethylamine (TEA) and its dibasic analogue, N,N′-dimethylpiperazine (DMPip), was studied and the resulting supramolecular complexes were analysed in the solid state, in solution and in the gas phase. In the solid state, 1:1 (2TEAH+·(ethyl-resorcinarene)2−·MeOH), 3:2 [DMPip·2DMPipH+·2(ethyl-resorcinarene−)] and 3:2 [2DMPip·DMPipH22+@(2methyl-ethyl-resorcinarene−)2·2MeOH] solid state complexes and interesting resorcinarene−⋯resorcinarene− supramolecular networks formed via enhanced hydrogen bonds involving the hydroxyl groups and the deprotonated hydroxyl groups of the resorcinarenes were observed. The host–guest complexe…

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Directional Shuttling of a Stimuli-Responsive Cone-Like Macrocycle on a Single-State Symmetric Dumbbell Axle

Rotaxane-based molecular shuttles are often operated using low-symmetry axles and changing the states of the binding stations. A molecular shuttle capable of directional shuttling of an acid-responsive cone-like macrocycle on a single-state symmetric dumbbell axle is now presented. The axle contains three binding stations: one symmetric di(quaternary ammonium) station and two nonsymmetric phenyl triazole stations arranged in opposite orientations. Upon addition of an acid, the protonated macrocycle shuttles from the di(quaternary ammonium) station to the phenyl triazole binding station closer to its butyl groups. This directional shuttling presumably originates from charge repulsion and an …

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Controlling the position of anions relative to a pentafluorophenyl groupw

The position of an anion above an electron-deficient arene can be controlled by the geometry of appended directing groups. Here a series of ammonium substituted pentafluorophenyl derivatives is investigated. The presented results are one step on the way to find the ideal structural features for an effective and superior receptor for anion–π studies.

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Concerted halogen and hydrogen bonding in [RuI2(H2dcbpy)(CO)2]···I2···(CH3OH)···I2···[RuI2(H2dcbpy)(CO)2].

A new type of concerted halogen bond-hydrogen bond interaction was found in the solid state structure of [RuI(2)(H(2)dcbpy)(CO)(2)]···I(2)···(MeOH)···I(2)···[RuI(2)(H(2)dcbpy)(CO)(2)]. The iodine atoms of the two I(2) molecules interact simultaneously with each other and with the OH group of methanol of crystallization. The interaction was characterized by single crystal X-ray measurements and by computational charge density analysis based on DFT calculations.

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Substituent Effect in 2-Benzoylmethylenequinoline Difluoroborates Exhibiting Through-Space Couplings. Multinuclear Magnetic Resonance, X-ray Diffraction, and Computational Study

The series of nine 2-benzoylmethylenequinoline difluoroborates have been synthesized and characterized by multinuclear magnetic resonance, X-ray diffraction (XRD), and computational methods. The through-space spin-spin couplings between (19)F and (1)H/(13)C nuclei have been observed in solution. The NMR chemical shifts have been correlated to the Hammett substituent constants. The crystal structures of six compounds have been solved by XRD. For two derivatives the X-ray wave function refinement was performed to evaluate the character of bonds in the NBF(2)O moiety by topological and integrated bond descriptors.

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2-(2-Iodoethyl)isoindole-1,3-dione

The title compound, C10H8INO2, is an N-substituted phthalimide derivative in which the crystallographic inter­molecular contact pattern consists of I⋯I, C—H⋯I, C—H⋯O and aromatic π–π inter­actions.

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Two (E)-2-({[4-(dialkylamino)phenyl]- imino}methyl)-4-nitrophenols

The slow evaporation of analytical NMR samples resulted in the formation of crystals of (E)-2-({[4-(dimethyl­amino)­phenyl]­imino}­methyl)-4-nitro­phenol, C15H15N3O3, (I), and (E)-2-({[4-(diethyl­amino)­phenyl]­imino}­methyl)-4-nitrophenol, C17H19N3O3, (II). Despite the small structural difference between these two N-salicylidene­aniline derivatives, they show different space groups and diverse mol­ecular packing. The mol­ecules of both compounds are close to being planar due to an intra­molecular O-H...N hydrogen bond. The 4-alkyl­amino-substituted benzene ring is inclined at an angle of 13.44 (19)° in (I) and 2.57 (8)° in (II) with respect to the 4-nitro-substituted phenol ring. Only very…

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cis,cis,cis-(Acetato-k2O,O´)bis[1,2-bis- (diphenylphosphanyl)ethane-k2P,P´]- ruthenium(II) 0.75-trifluoromethanesulfonate 0.25-chloride

In the title Ru(II) carboxyl-ate compound, [Ru(C2H3O2)(C26H24P2)2](CF3O3S)0.75Cl0.25, the distorted tris-bidentate octa-hedral stereochemistry about the Ru(II) atom in the complex cation comprises four P-atom donors from two 1,2-bis-(diphenyl-phosphan-yl)ethane ligands [Ru-P = 2.2881 (13)-2.3791 (13) Å] and two O-atom donors from the acetate ligand [Ru-O = 2.191 (3) and 2.202 (3) Å]. The disordered counter-anions are located on the same site in the structure in a 3:1 ratio, the expanded formula comprising four complex cations, three trifluoro-methane-sulfonate anions and one chloride anion, with two such formula units in the unit cell.

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Squaramide-Catalyzed Asymmetric aza-Friedel-Crafts/N,O-Acetalization Domino Reactions Between 2-Naphthols and Pyrazolinone Ketimines

N-Boc ketimines derived from pyrazolin-5-ones were explored to develop an unprecedented domino aza-Friedel-Crafts/N,O-acetalization reaction with 2-naphthols. The novel method requires a catalyst loading of only 0.5 mol % of a bifunctional squaramide catalyst, is scalable to gram amounts, and provides a new series of furanonaphthopyrazolidinone derivatives bearing two vicinal tetra-substituted stereogenic centers in excellent yields (95-98 %) and stereoselectivity (>99:1 d.r. and 97-98 % ee). A different reactivity was observed in the case of 1-naphthols and other electron-rich phenols, which led to the aza-Friedel-Crafts adducts in 70-98 % yield and 47-98 % ee.

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Association of 2-acylaminopyridines and benzoic acids. Steric and electronic substituent effect studied by XRD, solution and solid-state NMR and calculations

Abstract Eight single crystal X-ray structures, solid-state NMR spectroscopic, and theoretical studies utilizing QTAIM methodology were used to characterize the 2-acyl (alkyl in acyl = methyl, ethyl, t-butyl, and 1-adamantyl) amino-6-R-pyridine/4-R′-benzoic acid (R,R′ = H or Me) cocrystals. As expected among alkyl groups 1-adamantyl due to its bulkiness has the most significant effect on the relative positions of molecules in cocrystals. In addition, the subtle electronic and steric effects by the methyl substituents were observed. The theoretical calculations with full geometry optimizations are in agreement with the experimental findings (geometry, energy of hydrogen bonds). Based on the …

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Weak non-covalent interactions control the relative molecular orientation in the crystals of N-pentafluorobenzyl aniline derivatives

The crystal structures of N-pentafluorobenzyl aniline derivatives are controlled by versatile aromatic–aromatic interactions between the electron deficient and electron rich aromatics; the parent compound (1) possesses an L shape while protonation (2–5) induces a conformational change resulting in a planar arrangement of molecules which pack in layer type structures with different molecular orientations.

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The Halide Binding Behavior of 2-Carbamoyl-7-ureido-1H-indoles: Conformational Aspects

Indole-based anion receptors with an carboxamide unit in 2- and an urea in 7-position were prepared and found to bind halides (as well as acetate and nitrate) in chloroform solutions at room temperature. Investigations of the binding behaviour show that the receptor is selective for chloride. Surprisingly, the truncated receptor 3 without the 2-carbamoyl substituent shows the highest affinity for Cl–. Thorough 1H, 13C and 15N NMR investigations indicate different binding modes for acetate, nitrate and halides to the receptor 2. The observation of a major conformational change of this receptor during the binding of the halide ions leads to an understanding of the relative binding affinities …

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Cooperative Assistance in Bifunctional Organocatalysis: Enantioselective Mannich Reactions with Aliphatic and Aromatic Imines

both of which contain a thiourea moiety (Scheme 1).The catalysts are capable of deprotonating suitable nucleo-philes, such as activated carbonyl compounds. This proton-transfer reaction generates an ion pair, which is composed ofthe protonated catalyst and the anionic nucleophile interact-ing through hydrogen bonds. At least one of the NH moietiesin the protonated catalyst is involved in activating theelectrophilic reaction partner.

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N-[2-(2,2-Di­methyl­propanamido)­pyrimidin-4-yl]-2,2-di­methyl­propanamide n-hexane 0.25-solvate hemihydrate

The asymmetric unit of the title compound, C14H22N4O2·0.25C6H14·0.5H2O, contains two independent molecules of 2,4-bis(pivaloylamino)pyrimidine (M) with similar conformations, one water molecule and one-halfn-hexane solvent molecule situated on an inversion center. In one independentMmolecule, one of the twotert-butyl groups is rotationally disordered between two orientations in a 3:2 ratio. Then-hexane solvent molecule is disordered between two conformations in the same ratio. The water molecule bridges two independentMmoleculesviaO—H...O, N—H...O and O—H...N hydrogen bonds into a 2M·H2O unit, and these units are further linked by N—H...N hydrogen bonds into chains running in the [010] dire…

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Organocatalytic Domino Oxa-Michael/1,6-Addition Reactions: Asymmetric Synthesis of Chromans Bearing Oxindole Scaffolds.

An asymmetric organocatalytic domino oxa-Michael/1,6-addition reaction of ortho-hydroxyphenyl-substituted para-quinone methides and isatin-derived enoates has been developed. In the presence of 5 mol % of a bifunctional thiourea organocatalyst, this scalable domino reaction affords 4-phenyl-substituted chromans bearing spiro-connected oxindole scaffolds and three adjacent stereogenic centers in good to excellent yields (up to 98 %) and with very high stereoselectivities (up to >20:1 d.r., >99 % ee).

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Chiroptical inversion of a planar chiral redox-switchable rotaxane.

Reversible redox-switching of a planar chiral [2]rotaxane with a tetrathiafulvalene-bearing crown ether macrocycle generates a complete sign reversal of the main band in the ECD spectrum, as shown by experiment and rationalised by DFT calculations.

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ChemInform Abstract: Cooperative Assistance in Bifunctional Organocatalysis: Enantioselective Mannich Reactions with Aliphatic and Aromatic Imines.

both of which contain a thiourea moiety (Scheme 1).The catalysts are capable of deprotonating suitable nucleo-philes, such as activated carbonyl compounds. This proton-transfer reaction generates an ion pair, which is composed ofthe protonated catalyst and the anionic nucleophile interact-ing through hydrogen bonds. At least one of the NH moietiesin the protonated catalyst is involved in activating theelectrophilic reaction partner.

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Encapsulation of tetramethylphosphonium cations

International audience; The weak interactions and capsule formation of tetramethylphosphonium (TMP) cation with resorcinarenes 1 and 2 and the corresponding pyrogallarenes 3 and 4 were studied in the solid state by single crystal X-ray diffraction, in solution by NMR and in the gas phase by mass spectrometry. In methanol-D4, the NMR titration studies reveal that the association constants for the 1:1 complexes of TMP@3 and TMP@4 are much higher (TMP@4:390±37 M-1) than for the corresponding TMP@1 and TMP@2 (TMP@2:130±10 M-1) complexes. In the gas phase both monomeric 1:1 TMP@1-TMP@4 complexes as well as the dimeric 1:2 capsule complexes, TMP@12-TMP@42 were observed. The 1:1:2 molar mixtures o…

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cis,cis,cis-(Acetato-κ2O,O′)bis[1,2-bis(diphenylphosphanyl)ethane-κ2P,P′]ruthenium(II) 0.75-trifluoromethanesulfonate 0.25-chloride

In the title RuII carboxylate compound, [Ru(C2H3O2)(C26H24P2)2](CF3O3S)0.75Cl0.25, the distorted tris-bidentate octahedral stereochemistry about the RuII atom in the complex cation comprises four P-atom donors from two 1,2-bis(diphenylphosphanyl)ethane ligands [Ru—P = 2.2881 (13)–2.3791 (13) Å] and two O-atom donors from the acetate ligand [Ru—O = 2.191 (3) and 2.202 (3) Å]. The disordered counter-anions are located on the same site in the structure in a 3:1 ratio, the expanded formula comprising four complex cations, three trifluoromethanesulfonate anions and one chloride anion, with two such formula units in the unit cell.

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Non-Centrosymmetric Tetrameric Assemblies of Tetramethylammonium Halides with Uranyl Salophen Complexes in the Solid State

Ditopic salophen-UO(2) receptors 1-4 and 7 co-crystallize with tetramethylammonium (TMA) chloride and fluoride salts producing good quality crystals amenable for X-ray diffraction characterization. The arrangement of the receptor and salt units in the crystal lattice is such that tetrameric ball-shaped assemblies are formed, where an inner cluster of four TMA cations are surrounded by an outer shell of four UO(2)-bound anions. These elaborate architectures, which occur in all cases, regardless of a certain degree of structural modification on the receptors, lead to lattices that belong to non-centrosymmetric (NCS) space groups. Interestingly, the tetragonal symmetry of the tetrameric ball-s…

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Halogen Bonding Based “Catch and Release”: Reversible Solid State Entrapment of Elemental Iodine with Mono-Alkylated DABCO Salts

The halogen bonding (XB) between elemental iodine (I2) and neutral 1,4-diazabicyclo[2.2.2]octane (DABCO) and its monoalkylated PF6– salts was studied by X-ray crystallographic, thermoanalytical, and computational methods. DABCO was found to form both 1:1 and 1:2 complexes with I2 showing an exceptionally strong halogen bond (ΔEcp = −73.0 kJ/mol) with extremely short N···I distance (2.37 A) in the 1:1 complex (1a). In the more favored 1:2 complex (1b), the XB interaction was found to be slightly weaker [ΔEcp = −64.4 kJ/mol and d(N···I) = 2.42 A] as compared to 1a. The monoalkylated DABCO salts (2PF6–7PF6) form corresponding 1:1 XB complexes with I2 {[2···I2]PF6–([7···I2]PF6} similarly to the…

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Carbon’s Three-Center-Four-Electron Tetrel Bond, Treated Experimentally

Tetrel bonding is the noncovalent interaction of group IV elements with electron donors. It is a weak, directional interaction that resembles hydrogen and halogen bonding yet remains barely explored. Herein, we present an experimental investigation of the carbon-centered, three-center, four-electron tetrel bond, [N−C− N]+ , formed by capturing a carbenium ion with a bidentate Lewis base. NMRspectroscopic, titration-calorimetric, and reaction-kinetic evidence for the existence and structure of this species is reported. The studied interaction is by far the strongest tetrel bond reported so far and is discussed in comparison with the analogous halogen bond. The necessity of the involvement of…

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X-ray structures of five variably tert-butoxycarbonyl-substituted adenines and their liquid and solid state NMR investigations

Abstract Adenine reacts selectively with di- tert -butyldicarbonate in THF in the presence of NaOH to give N 9-monoBoc-adenine 1 . The molecular structure and crystal packing of this and four other variably substituted Boc-derivatives of adenine were determined in solid state by means of X-ray diffraction and CP/MAS NMR experiments and characterized in liquid state by 1 H, 13 C, and 15 N NMR spectroscopy as well. Additionally, crystal structure of inclusion compound between N 6 -monoBoc-adenine 5 and CHCl 3 is reported. Tautomeric equilibria of mono- and disubstituted derivatives 4 and 5 in liquid state were studied by VT NMR experiments.

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Bile acid-derived mono- and diketals—synthesis, structural characterization and self-assembling properties

Three oxo-derivatives of bile acid methyl esters have been used as starting compounds in the preparation of novel bile acid monoketals with 1,2-benzenediol (catechol) and 2,3-naphthalenediol, as well as mono- and diketals with pentaerythritol. Monoketals of pentaerythritol showed a tendency to form thermoreversible gels in many aromatic solvents and the methyl lithocholate derivative proved to be a supergelator able to form a gel with t-butylbenzene at a concentration as low as 0.5% w/v. Whereas the naphthalenediol ketals formed film-type materials in the studied solvents, the catechol ketals underwent rapid crystallization into X-ray quality single crystals. Single crystal X-ray structures…

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Mukaiyama–Michael Reactions with Acrolein and Methacrolein: A Catalytic Enantioselective Synthesis of the C17–C28 Fragment of Pectenotoxins

Enantioselective iminium-catalyzed reactions with acrolein and methacrolein are rare. A catalytic enantioselective Mukaiyama-Michael reaction that readily accepts acrolein or methacrolein as substrates, affording the products in good yields and 91-97% ee, is presented. As an application of the methodology, an enantioselective route to the key C17-C28 segment of the pectenotoxin using the Mukaiyama-Michael reaction as the key step is described.

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Alternative Motifs for Halogen Bonding (Eur. J. Org. Chem. 9/2013)

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ChemInform Abstract: Palladium-Catalyzed Dehydrogenative β′-Functionalization of β-Keto Esters with Indoles at Room Temperature.

The dehydrogenative β′-functionalization of α-substituted β-keto esters with indoles proceeds with high regioselectivities (C3-selective for the indole partner and β′-selective for the β-keto ester) and good yields under mild palladium catalysis at room temperature with a variety of oxidants. Two possible mechanisms involving either late or early involvement of indole are presented.

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Synthesis of isomorphous cobalt and nickel thiocyanate coordination compounds: Effect of metals on compound properties

The reaction of 2-methylpiperazine with the thiocyanate ligand and two transition metals leads to the production of two new isomorphous [ML2SCN4] where L is the 2-methylpiperazine and [M =Co (1), and Ni (2)], presenting an octahedral configuration. These compounds were characterized by single crystal X-ray crystallography, TG-DTA analysis, as well as infrared and UV-Vis spectroscopy and TG-DTA. The magnetic and antibacterial properties were also determined. Through the link with N-H···S hydrogen bonds, a global 3D network was established. The studied compounds show the metal center’s impact leading to different properties. Indeed, the first compound shows high spin orbit coupling, whereas t…

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Synthesis, crystal structure, DFT calculations, Hirshfeld surface, vibrational and optical properties of a novel hybrid non-centrosymmetric material (C10H15N2)2H2P2O7

This present work undertakes the study of a novel organic–inorganic hybrid material, which has been obtained successfully by an acid-base reaction at room temperature and structurally studied by the single crystal X-ray diffraction method. (C10H15N2)2H2P2O7 crystallizes in the triclinic system with the non-centrosymmetric space group P1 with the following lattice parameters: a = 5.9159(2) Å, b = 13.8451(6) Å, c = 14.5973(5) Å, ? = 74.507(2)°, ? = 89.980(2)°, ? = 89.231(2)° with V = 1152.06(8) Å3 and Z = 2. The X-ray structural analysis supported by a detailed Hirshfeld 2D fingerprint plots has been performed to elucidate the different inter-contacts in the crystal structure mainly associate…

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Anion-π Interaction: An Influential Force in Solid State Molecular Microstructures

The crystal structures of simple triphenyl(pentafluorobenzyl)phosphonium salts provide crucial data on the influence of anion size on the molecular structure of bis(pentafluorobenzyl)phosphonium cations containing two adjacent electron-deficient moieties. Whereas the bromide anions interact by anion-π interaction in a 1:1 mode with the pentafluorobenzene unit Z-configured, the bulkier anions iodide, tetrafluoroborate, and hexafluorophosphate result in a 1:2 tweezer-like anti-configuration in which one anion interacts simultaneously with two pentafluorobenzene units. When spatial separation of the two electron-deficient rings match the size of the anion, anion-π interactions induce a conform…

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N 2,N 2,N 6,N 6-Tetra­kis(2,3,4,5,6-penta­fluoro­benzo­yl)pyridine-2,6-diamine

The title compound, C33H3F20N3O4, is a highly fluorinated organic imide that was isolated as an unexpected product from the reaction of 2,6-diaminopyridine with 2,3,4,5,6-pentafluorobenzoyl chloride in a 1:2 molar ratio. The molecule is located on a twofold axis and one of its symmetry-independent 2,3,4,5,6-pentafluorobenzoyl groups is disordered over two sets of sites, the occupancy of the major component being 0.773 (3). In the major component, the dihedral angle between the perfluorophenyl groups is 63.64 (10)°, and these groups form dihedral angles of 67.14 (7) and 21.1 (2)° with the pyridine core. Short intermolecular C&#821…

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Geometrically diverse anions in anion–π interactions

The role of different anion geometries in anion–π interactions is discussed. The chemistry described herein is different to the interaction of spherical cations with aromatics. The influence of different geometries makes selective anion recognition more complicated than respective cation sensing. The present structural study reveals attractive interactions between pentafluorophenyl units and geometrically diverse anions (linear, trigonal planar, tetrahedral and octahedral). Due to the electrostatic nature of anion–π interactions, the anion geometry seems to be irrelevant. The size of the anion controls the relative orientation of the anion and the π system (e.g. in compounds 1–3). The dimer…

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A convenient route for the preparation of the monohydride catalyst trans-[RuCl(H)(dppe)2] (dppe=Ph2PCH2CH2PPh2): improved synthesis and crystal structure

Abstract A novel and improved room temperature synthesis of the monohydride catalyst trans-[RuCl(H)(dppe)2] complex (1, dppe (1,2-bis(diphenylphosphino)ethane) = Ph2PCH2CH2PPh2) proceeds through oxidation of methanol (the solvent) by the pentacoordinated cis-[RuCl(dppe)2][PF6] complex and t-BuOK as the base is described. Compound 1 was fully characterized by NMR (1H, 13C, 31P), ESI-MS(TOF +), FTIR and elemental analysis. The X-ray structure of 1 was reported for the first time and unambiguously confirms the trans-configuration of the complex.

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N-[2-(2,2-Dimethylpropanamido)- pyrimidin-4-yl]-2,2-dimethyl- propanamide n-hexane 0.25-solvate hemihydrate

The asymmetric unit of the title compound, C₁₄H₂₂N₄O₂·0.25C₆H₁₄·0.5H₂O, contains two independent molecules of 2,4-bis(pivaloylamino)pyrimidine (M) with similar conformations, one water molecule and one-half n-hexane solvent molecule situated on an inversion center. In one independent M molecule, one of the two tert-butyl groups is rotationally disordered between two orientations in a 3:2 ratio. The n-hexane solvent molecule is disordered between two conformations in the same ratio. The water molecule bridges two independent M molecules via O-H...O, N-H...O and O-H...N hydrogen bonds into a 2M·H₂O unit, and these units are further linked by N-H...N hydrogen bonds into chains running in the […

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Encapsulation of secondary and tertiary ammonium salts by resorcinarenes and pyrogallarenes: the effect of size and charge concentration

The binding of different categories of alkyl ammonium (secondary and tertiary mono- and di-ammonium) salts with resorcinarenes and a pyrogallarene through weak interactions was analysed in all phases. 1H NMR spectroscopy and electrospray ionisation mass spectrometry were utilized in analysing the complexes in solution and in the gas phase, respectively. The 1H NMR titration studies in methanol-d4 reveal that the association constants for the 1:1 complexes vary according to the electronic properties of the hosts as well as the size, geometric orientation and charge concentration of the guest cations with binding constants of up to 950 M−1 in some cases. Mass spectrometry reveals 1:1 monomeri…

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Syntheses and structural study of bile acid amidoalcohols.

Preparation, structural and thermoanalytical characterization of fourteen N-hydroxyalkyl 5beta-cholan-24-amides have been performed in this study. The utilized techniques include liquid state and CP-MAS 13C NMR spectroscopy, thermogravimetry, differential scanning calorimetry, and also powder and single crystal X-ray crystallography. The results were discussed and compared to each other and also to previous findings on similar compounds. One pure hydrate form was obtained. Six new single crystal structures were determined, including one hydrated chloroform solvate. Decomposition temperatures were found to correlate with the side chain length, and the number of the hydroxyl groups. The spati…

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Anion–π Interactions in Salts with Polyhalide Anions: Trapping of I 4 2−

The directionality of interaction of electron-deficient π systems with spherical anions (e.g,. halides) can be controlled by secondary effects like NH or CH hydrogen bonding. In this study a series of pentafluorophenyl-substituted salts with polyhalide anions is investigated. The compounds are obtained by aerobic oxidation of the corresponding halide upon crystallization. Solid-state structures reveal that in bromide 2, directing NH-anion interactions position the bromide ion in an η(1)-type fashion over but not in the center of the aromatic ring. The same directing forces are effective in corresponding tribromide salt 3. In the crystal, the bromide ion is paneled by four electron-deficient…

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CCDC 967090: Experimental Crystal Structure Determination

Related Article: Michael Giese, Markus Albrecht, Simon Steike, Anton Ackermann, Arto Valkonen, and Kari Rissanen|2013|Inorg.Chem.|52|7666|doi:10.1021/ic4008087

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CCDC 990706: Experimental Crystal Structure Determination

Related Article: N. Kodiah Beyeh, Altti Ala-Korpi, Mario Cetina, Arto Valkonen, Kari Rissanen|2014|Chem.-Eur.J.|20|15144|doi:10.1002/chem.201402533

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CCDC 915608: Experimental Crystal Structure Determination

Related Article: Michael Giese, Markus Albrecht, Arto Valkonen, Kari Rissanen|2013|Eur.J.Org.Chem.|2013|3247|doi:10.1002/ejoc.201201704

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CCDC 1555956: Experimental Crystal Structure Determination

Related Article: Disha Mungalpara, Arto Valkonen, Kari Rissanen, Stefan Kubik|2017|Chemical Science|8|6005|doi:10.1039/C7SC02700A

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CCDC 1910670: Experimental Crystal Structure Determination

Related Article: Marius Gaedke, Felix Witte, Jana Anhäuser, Henrik Hupatz, Hendrik V. Schröder, Arto Valkonen, Kari Rissanen, Arne Lützen, Beate Paulus, Christoph A. Schalley |2019|Chemical Science|10|10003|doi:10.1039/C9SC03694F

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CCDC 901286: Experimental Crystal Structure Determination

Related Article: Anna Zakrzewska, Erkki Kolehmainen, Arto Valkonen, Esa Haapaniemi, Kari Rissanen, Lilianna Chęcińska, and Borys Ośmiałowski|2013|J.Phys.Chem.A|117|252|doi:10.1021/jp311072q

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CCDC 990709: Experimental Crystal Structure Determination

Related Article: N. Kodiah Beyeh, Altti Ala-Korpi, Mario Cetina, Arto Valkonen, Kari Rissanen|2014|Chem.-Eur.J.|20|15144|doi:10.1002/chem.201402533

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CCDC 1577841: Experimental Crystal Structure Determination

Related Article: Yan-Long Ma, Hua Ke, Arto Valkonen, Kari Rissanen, Wei Jiang|2018|Angew.Chem.,Int.Ed.|57|709|doi:10.1002/anie.201711077

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CCDC 1581474: Experimental Crystal Structure Determination

Related Article: Alavi Karim, Nils Schulz, Hanna Andersson, Bijan Nekoueishahraki, Anna-Carin C. Carlsson, Daniel Sarabi, Arto Valkonen, Kari Rissanen, Jürgen Gräfenstein, Sandro Keller, Máté Erdélyi|2018|J.Am.Chem.Soc.|140|17571|doi:10.1021/jacs.8b09367

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CCDC 957915: Experimental Crystal Structure Determination

Related Article: Borys Ośmiałowski, Erkki Kolehmainen, Krzysztof Ejsmont, Satu Ikonen, Arto Valkonen, Kari Rissanen, Nonappa|2013|J.Mol.Struct.|1054|157|doi:10.1016/j.molstruc.2013.09.047

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CCDC 1005283: Experimental Crystal Structure Determination

Related Article: Michael Giese, Markus Albrecht, Arto Valkonen, Kari Rissanen|2015|Chemical Science|6|354|doi:10.1039/C4SC02762K

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CCDC 967091: Experimental Crystal Structure Determination

Related Article: Michael Giese, Markus Albrecht, Simon Steike, Anton Ackermann, Arto Valkonen, and Kari Rissanen|2013|Inorg.Chem.|52|7666|doi:10.1021/ic4008087

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CCDC 1575263: Experimental Crystal Structure Determination

Related Article: Yan-Long Ma, Hua Ke, Arto Valkonen, Kari Rissanen, Wei Jiang|2018|Angew.Chem.,Int.Ed.|57|709|doi:10.1002/anie.201711077

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CCDC 1040204: Experimental Crystal Structure Determination

Related Article: Markus Albrecht, Yi Hai, Okan Köksal, Gerhard Raabe, Fangfang Pan, Arto Valkonen and Kari Rissanen|2016|Chem.-Eur.J.|22|6596|doi:10.1002/chem.201600249

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CCDC 1005269: Experimental Crystal Structure Determination

Related Article: Michael Giese, Markus Albrecht, Arto Valkonen, Kari Rissanen|2015|Chemical Science|6|354|doi:10.1039/C4SC02762K

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CCDC 1519434: Experimental Crystal Structure Determination

Related Article: Arto Valkonen, Giuseppe M. Lombardo, Kari Rissanen, Francesco Punzo, Massimo Cametti|2017|Dalton Trans.|46|5240|doi:10.1039/C6DT04773D

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CCDC 2061197: Experimental Crystal Structure Determination

Related Article: Lauri Happonen, J. Mikko Rautiainen, Arto Valkonen|2021|Cryst.Growth Des.|21|3409|doi:10.1021/acs.cgd.1c00183

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CCDC 1868319: Experimental Crystal Structure Determination

Related Article: Souaibou Yaouba, Arto Valkonen, Paolo Coghi, Jiaying Gao, Eric M. Guantai, Solomon Derese, Vincent K. W. Wong, Máté Erdélyi, Abiy Yenesew|2018|Molecules|23|3199|doi:10.3390/molecules23123199

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CCDC 969817: Experimental Crystal Structure Determination

Related Article: N. Kodiah Beyeh, Arto Valkonen, Kari Rissanen|2014|CrystEngComm|16|3758|doi:10.1039/C3CE42291G

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CCDC 1846187: Experimental Crystal Structure Determination

Related Article: Martin Fries, Meike Mertens, Nico Teske, Markus Kipp, Cordian Beyer, Thomas Willms, Arto Valkonen, Kari Rissanen, Markus Albrecht, and Tim Clarner|2019|ACS Omega|4|1685|doi:10.1021/acsomega.8b02523

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CCDC 1453996: Experimental Crystal Structure Determination

Related Article: Jashobanta Sahoo, Rajendran Arunachalam, Palani S. Subramanian, Eringathodi Suresh, Arto Valkonen, Kari Rissanen, Markus Albrecht|2016|Angew.Chem.,Int.Ed.|55|9625|doi:10.1002/anie.201604093

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CCDC 1005280: Experimental Crystal Structure Determination

Related Article: Michael Giese, Markus Albrecht, Arto Valkonen, Kari Rissanen|2015|Chemical Science|6|354|doi:10.1039/C4SC02762K

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CCDC 1894864: Experimental Crystal Structure Determination

Related Article: Sivagnana Subramanian, Rajendran Arunachalam, Eswaran Chinnaraja, Arto Valkonen, Kari Rissanen|2019|Appl.Organomet.Chem.|33|e5202|doi:10.1002/aoc.5202

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CCDC 1005278: Experimental Crystal Structure Determination

Related Article: Michael Giese, Markus Albrecht, Arto Valkonen, Kari Rissanen|2015|Chemical Science|6|354|doi:10.1039/C4SC02762K

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CCDC 936269: Experimental Crystal Structure Determination

Related Article: Michael Giese, Markus Albrecht, Tatjana Repenko, Johannes Sackmann, Arto Valkonen, Kari Rissanen|2014|Eur.J.Org.Chem.|2014|2435|doi:10.1002/ejoc.201301336

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CCDC 1995537: Experimental Crystal Structure Determination

Related Article: Hai Yi, Markus Albrecht, Fangfang Pan, Arto Valkonen, Kari Rissanen|2020|Eur.J.Org.Chem.||6073|doi:10.1002/ejoc.202001008

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CCDC 906031: Experimental Crystal Structure Determination

Related Article: Pekka K.Poutiainen ,Jorma J.Palvimo,Ari E.Hinkkanen,Arto Valkonen,Topi K.Vaisanen,Reino Laatikainen,Juha T.Pulkkinen|2013|J.Med.Chem.|56|1064|doi:10.1021/jm301516q

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CCDC 1014209: Experimental Crystal Structure Determination

Related Article: Anna Zakrzewska, Erkki Kolehmainen, Arto Valkonen, Esa Haapaniemi, Kari Rissanen, Lilianna Chęcińska, and Borys Ośmiałowski|2013|J.Phys.Chem.A|117|252|doi:10.1021/jp311072q

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CCDC 936267: Experimental Crystal Structure Determination

Related Article: Michael Giese, Markus Albrecht, Tatjana Repenko, Johannes Sackmann, Arto Valkonen, Kari Rissanen|2014|Eur.J.Org.Chem.|2014|2435|doi:10.1002/ejoc.201301336

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CCDC 1005287: Experimental Crystal Structure Determination

Related Article: Michael Giese, Markus Albrecht, Arto Valkonen, Kari Rissanen|2015|Chemical Science|6|354|doi:10.1039/C4SC02762K

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CCDC 1014201: Experimental Crystal Structure Determination

Related Article: Hai Yi, Markus Albrecht, Arto Valkonen, Kari Rissanen|2015|New J.Chem.|39|746|doi:10.1039/C4NJ01654H

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CCDC 915600: Experimental Crystal Structure Determination

Related Article: Michael Giese, Markus Albrecht, Arto Valkonen, Kari Rissanen|2013|Eur.J.Org.Chem.|2013|3247|doi:10.1002/ejoc.201201704

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CCDC 915601: Experimental Crystal Structure Determination

Related Article: Michael Giese, Markus Albrecht, Arto Valkonen, Kari Rissanen|2013|Eur.J.Org.Chem.|2013|3247|doi:10.1002/ejoc.201201704

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CCDC 1846185: Experimental Crystal Structure Determination

Related Article: Martin Fries, Meike Mertens, Nico Teske, Markus Kipp, Cordian Beyer, Thomas Willms, Arto Valkonen, Kari Rissanen, Markus Albrecht, and Tim Clarner|2019|ACS Omega|4|1685|doi:10.1021/acsomega.8b02523

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CCDC 1443004: Experimental Crystal Structure Determination

Related Article: Guobao Huang, Arto Valkonen, Kari Rissanen, Wei Jiang|2016|Chem.Commun.|52|9078|doi:10.1039/C6CC00349D

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CCDC 1539540: Experimental Crystal Structure Determination

Related Article: David Van Craen, Wolfgang H. Rath, Marina Huth, Laura Kemp, Christoph Räuber, Jan M. Wollschläger, Christoph A. Schalley, Arto Valkonen, Kari Rissanen, Markus Albrecht|2017|J.Am.Chem.Soc.|139|16959|doi:10.1021/jacs.7b10098

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A conformationally adaptive macrocycle: conformational complexity and host–guest chemistry of zorb[4]arene

Large amplitude conformational change is one of the features of biomolecular recognition and is also the basis for allosteric effects and signal transduction in functional biological systems. However, synthetic receptors with controllable conformational changes are rare. In this article, we present a thorough study on the host–guest chemistry of a conformationally adaptive macrocycle, namely per-O-ethoxyzorb[4]arene (ZB4). Similar to per-O-ethoxyoxatub[4]arene, ZB4 is capable of accommodating a wide range of organic cations. However, ZB4 does not show large amplitude conformational responses to the electronic substituents on the guests. Instead of a linear free-energy relationship, ZB4 foll…

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CCDC 915607: Experimental Crystal Structure Determination

Related Article: Michael Giese, Markus Albrecht, Arto Valkonen, Kari Rissanen|2013|Eur.J.Org.Chem.|2013|3247|doi:10.1002/ejoc.201201704

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CCDC 1868324: Experimental Crystal Structure Determination

Related Article: Souaibou Yaouba, Arto Valkonen, Paolo Coghi, Jiaying Gao, Eric M. Guantai, Solomon Derese, Vincent K. W. Wong, Máté Erdélyi, Abiy Yenesew|2018|Molecules|23|3199|doi:10.3390/molecules23123199

research product

CCDC 1040206: Experimental Crystal Structure Determination

Related Article: Markus Albrecht, Yi Hai, Okan Köksal, Gerhard Raabe, Fangfang Pan, Arto Valkonen and Kari Rissanen|2016|Chem.-Eur.J.|22|6596|doi:10.1002/chem.201600249

research product

CCDC 1868322: Experimental Crystal Structure Determination

Related Article: Souaibou Yaouba, Arto Valkonen, Paolo Coghi, Jiaying Gao, Eric M. Guantai, Solomon Derese, Vincent K. W. Wong, Máté Erdélyi, Abiy Yenesew|2018|Molecules|23|3199|doi:10.3390/molecules23123199

research product

CCDC 1519435: Experimental Crystal Structure Determination

Related Article: Arto Valkonen, Giuseppe M. Lombardo, Kari Rissanen, Francesco Punzo, Massimo Cametti|2017|Dalton Trans.|46|5240|doi:10.1039/C6DT04773D

research product

CCDC 2061192: Experimental Crystal Structure Determination

Related Article: Lauri Happonen, J. Mikko Rautiainen, Arto Valkonen|2021|Cryst.Growth Des.|21|3409|doi:10.1021/acs.cgd.1c00183

research product

CCDC 957918: Experimental Crystal Structure Determination

Related Article: Borys Ośmiałowski, Erkki Kolehmainen, Krzysztof Ejsmont, Satu Ikonen, Arto Valkonen, Kari Rissanen, Nonappa|2013|J.Mol.Struct.|1054|157|doi:10.1016/j.molstruc.2013.09.047

research product

CCDC 1040201: Experimental Crystal Structure Determination

Related Article: Markus Albrecht, Yi Hai, Okan Köksal, Gerhard Raabe, Fangfang Pan, Arto Valkonen and Kari Rissanen|2016|Chem.-Eur.J.|22|6596|doi:10.1002/chem.201600249

research product

CCDC 2171093: Experimental Crystal Structure Determination

Related Article: J. Mikko Rautiainen, Maryna Green, Minna Mähönen, Jani O. Moilanen, Manu Lahtinen, Arto Valkonen|2023|Cryst.Growth Des.|23|2361|doi:10.1021/acs.cgd.2c01351

research product

CCDC 2171080: Experimental Crystal Structure Determination

Related Article: J. Mikko Rautiainen, Maryna Green, Minna Mähönen, Jani O. Moilanen, Manu Lahtinen, Arto Valkonen|2023|Cryst.Growth Des.|23|2361|doi:10.1021/acs.cgd.2c01351

research product

CCDC 957920: Experimental Crystal Structure Determination

Related Article: Borys Ośmiałowski, Erkki Kolehmainen, Krzysztof Ejsmont, Satu Ikonen, Arto Valkonen, Kari Rissanen, Nonappa|2013|J.Mol.Struct.|1054|157|doi:10.1016/j.molstruc.2013.09.047

research product

CCDC 1005272: Experimental Crystal Structure Determination

Related Article: Michael Giese, Markus Albrecht, Arto Valkonen, Kari Rissanen|2015|Chemical Science|6|354|doi:10.1039/C4SC02762K

research product

CCDC 1995533: Experimental Crystal Structure Determination

Related Article: Hai Yi, Markus Albrecht, Fangfang Pan, Arto Valkonen, Kari Rissanen|2020|Eur.J.Org.Chem.||6073|doi:10.1002/ejoc.202001008

research product

CCDC 841777: Experimental Crystal Structure Determination

Related Article: Borys Ośmiałowski , Erkki Kolehmainen , Satu Ikonen , Arto Valkonen , Adam Kwiatkowski , Izabela Grela , and Esa Haapaniemi|2012|J.Org.Chem.|77|9609|doi:10.1021/jo301643z

research product

CCDC 1995536: Experimental Crystal Structure Determination

Related Article: Hai Yi, Markus Albrecht, Fangfang Pan, Arto Valkonen, Kari Rissanen|2020|Eur.J.Org.Chem.||6073|doi:10.1002/ejoc.202001008

research product

CCDC 1995534: Experimental Crystal Structure Determination

Related Article: Hai Yi, Markus Albrecht, Fangfang Pan, Arto Valkonen, Kari Rissanen|2020|Eur.J.Org.Chem.||6073|doi:10.1002/ejoc.202001008

research product

CCDC 1532334: Experimental Crystal Structure Determination

Related Article: Guo-Bao Huang, Wei-Er Liu, Arto Valkonen, Huan Yao, Kari Rissanen, Wei Jiang|2018|Chin.Chem.Lett.|29|91|doi:10.1016/j.cclet.2017.07.005

research product

CCDC 990707: Experimental Crystal Structure Determination

Related Article: N. Kodiah Beyeh, Altti Ala-Korpi, Mario Cetina, Arto Valkonen, Kari Rissanen|2014|Chem.-Eur.J.|20|15144|doi:10.1002/chem.201402533

research product

CCDC 1005277: Experimental Crystal Structure Determination

Related Article: Michael Giese, Markus Albrecht, Arto Valkonen, Kari Rissanen|2015|Chemical Science|6|354|doi:10.1039/C4SC02762K

research product

CCDC 1038851: Experimental Crystal Structure Determination

Related Article: N. Kodiah Beyeh, Arto Valkonen, Sandip Bhowmik, Fangfang Pan, K. Rissanen|2015|Org.Chem.Front.|2|340|doi:10.1039/C4QO00326H

research product

CCDC 1868321: Experimental Crystal Structure Determination

Related Article: Souaibou Yaouba, Arto Valkonen, Paolo Coghi, Jiaying Gao, Eric M. Guantai, Solomon Derese, Vincent K. W. Wong, Máté Erdélyi, Abiy Yenesew|2018|Molecules|23|3199|doi:10.3390/molecules23123199

research product

CCDC 1519437: Experimental Crystal Structure Determination

Related Article: Arto Valkonen, Giuseppe M. Lombardo, Kari Rissanen, Francesco Punzo, Massimo Cametti|2017|Dalton Trans.|46|5240|doi:10.1039/C6DT04773D

research product

CCDC 1575262: Experimental Crystal Structure Determination

Related Article: Yan-Long Ma, Hua Ke, Arto Valkonen, Kari Rissanen, Wei Jiang|2018|Angew.Chem.,Int.Ed.|57|709|doi:10.1002/anie.201711077

research product

CCDC 1539541: Experimental Crystal Structure Determination

Related Article: David Van Craen, Wolfgang H. Rath, Marina Huth, Laura Kemp, Christoph Räuber, Jan M. Wollschläger, Christoph A. Schalley, Arto Valkonen, Kari Rissanen, Markus Albrecht|2017|J.Am.Chem.Soc.|139|16959|doi:10.1021/jacs.7b10098

research product

CCDC 922097: Experimental Crystal Structure Determination

Related Article: Agnieszka Skotnicka, Erkki Kolehmainen, Przemysław Czeleń, Arto Valkonen, Ryszard Gawinecki|2013|Int.J.Mol.Sci.|14|4444|doi:10.3390/ijms14034444

research product

CCDC 967092: Experimental Crystal Structure Determination

Related Article: Michael Giese, Markus Albrecht, Simon Steike, Anton Ackermann, Arto Valkonen, and Kari Rissanen|2013|Inorg.Chem.|52|7666|doi:10.1021/ic4008087

research product

CCDC 969818: Experimental Crystal Structure Determination

Related Article: N. Kodiah Beyeh, Arto Valkonen, Kari Rissanen|2014|CrystEngComm|16|3758|doi:10.1039/C3CE42291G

research product

CCDC 1505706: Experimental Crystal Structure Determination

Related Article: Disha Mungalpara, Harald Kelm, Arto Valkonen, Kari Rissanen, Sandro Keller, Stefan Kubik|2017|Org.Biomol.Chem.|15|102|doi:10.1039/C6OB02172G

research product

CCDC 915606: Experimental Crystal Structure Determination

Related Article: Michael Giese, Markus Albrecht, Arto Valkonen, Kari Rissanen|2013|Eur.J.Org.Chem.|2013|3247|doi:10.1002/ejoc.201201704

research product

CCDC 915603: Experimental Crystal Structure Determination

Related Article: Michael Giese, Markus Albrecht, Arto Valkonen, Kari Rissanen|2013|Eur.J.Org.Chem.|2013|3247|doi:10.1002/ejoc.201201704

research product

CCDC 990708: Experimental Crystal Structure Determination

Related Article: N. Kodiah Beyeh, Altti Ala-Korpi, Mario Cetina, Arto Valkonen, Kari Rissanen|2014|Chem.-Eur.J.|20|15144|doi:10.1002/chem.201402533

research product

CCDC 967128: Experimental Crystal Structure Determination

Related Article: Michael Giese, Markus Albrecht, Christian Bohnen, Tatjana Repenko, Arto Valkonen, Kari Rissanen|2014|Dalton Trans.|43|1873|doi:10.1039/C3DT52960F

research product

CCDC 1453997: Experimental Crystal Structure Determination

Related Article: Jashobanta Sahoo, Rajendran Arunachalam, Palani S. Subramanian, Eringathodi Suresh, Arto Valkonen, Kari Rissanen, Markus Albrecht|2016|Angew.Chem.,Int.Ed.|55|9625|doi:10.1002/anie.201604093

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CCDC 1040203: Experimental Crystal Structure Determination

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CCDC 2171079: Experimental Crystal Structure Determination

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CCDC 841780: Experimental Crystal Structure Determination

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Achieving Strong Positive Cooperativity through Activating Weak Non‐Covalent Interactions

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CCDC 967093: Experimental Crystal Structure Determination

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CCDC 1036897: Experimental Crystal Structure Determination

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CCDC 915605: Experimental Crystal Structure Determination

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CCDC 1935511: Experimental Crystal Structure Determination

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CCDC 1922829: Experimental Crystal Structure Determination

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CCDC 967129: Experimental Crystal Structure Determination

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CCDC 2171088: Experimental Crystal Structure Determination

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CCDC 900513: Experimental Crystal Structure Determination

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endo-Functionalized molecular tubes: selective encapsulation of neutral molecules in non-polar media

Four endo-functionalized molecular tubes show high binding affinity and selectivity to neutral molecules.

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CCDC 1826426: Experimental Crystal Structure Determination

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CCDC 1995535: Experimental Crystal Structure Determination

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CCDC 1555958: Experimental Crystal Structure Determination

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CCDC 1484545: Experimental Crystal Structure Determination

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CCDC 936265: Experimental Crystal Structure Determination

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CCDC 1005267: Experimental Crystal Structure Determination

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CCDC 1918923: Experimental Crystal Structure Determination

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CCDC 957919: Experimental Crystal Structure Determination

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CCDC 2171091: Experimental Crystal Structure Determination

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CCDC 2171089: Experimental Crystal Structure Determination

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CCDC 1005275: Experimental Crystal Structure Determination

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CCDC 921455: Experimental Crystal Structure Determination

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CCDC 1005268: Experimental Crystal Structure Determination

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CCDC 1014211: Experimental Crystal Structure Determination

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CCDC 2061201: Experimental Crystal Structure Determination

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CCDC 1422861: Experimental Crystal Structure Determination

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research product

CCDC 969816: Experimental Crystal Structure Determination

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CCDC 957917: Experimental Crystal Structure Determination

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CCDC 1005281: Experimental Crystal Structure Determination

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CCDC 957914: Experimental Crystal Structure Determination

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CCDC 1835264: Experimental Crystal Structure Determination

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CCDC 1519433: Experimental Crystal Structure Determination

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CCDC 1040207: Experimental Crystal Structure Determination

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CCDC 2061186: Experimental Crystal Structure Determination

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CCDC 2005907: Experimental Crystal Structure Determination

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research product

CCDC 2171081: Experimental Crystal Structure Determination

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CCDC 2171090: Experimental Crystal Structure Determination

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research product

CCDC 1038850: Experimental Crystal Structure Determination

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research product

CCDC 2171087: Experimental Crystal Structure Determination

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research product

CCDC 1014200: Experimental Crystal Structure Determination

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CCDC 1581480: Experimental Crystal Structure Determination

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research product

CCDC 1868320: Experimental Crystal Structure Determination

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research product

CCDC 2171086: Experimental Crystal Structure Determination

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research product

CCDC 1555957: Experimental Crystal Structure Determination

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research product

CCDC 1036895: Experimental Crystal Structure Determination

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research product

CCDC 1894863: Experimental Crystal Structure Determination

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research product

CCDC 2061190: Experimental Crystal Structure Determination

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CCDC 1900203: Experimental Crystal Structure Determination

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research product

CCDC 1005286: Experimental Crystal Structure Determination

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research product

CCDC 967096: Experimental Crystal Structure Determination

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CCDC 936266: Experimental Crystal Structure Determination

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research product

CCDC 922456: Experimental Crystal Structure Determination

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research product

CCDC 1422862: Experimental Crystal Structure Determination

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research product

CCDC 2061198: Experimental Crystal Structure Determination

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research product

CCDC 2061193: Experimental Crystal Structure Determination

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research product

CCDC 882325: Experimental Crystal Structure Determination

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research product

CCDC 1836247: Experimental Crystal Structure Determination

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research product

CCDC 922453: Experimental Crystal Structure Determination

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research product

CCDC 1836509: Experimental Crystal Structure Determination

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research product

CCDC 901285: Experimental Crystal Structure Determination

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research product

CCDC 1828064: Experimental Crystal Structure Determination

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research product

CCDC 1005273: Experimental Crystal Structure Determination

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research product

CCDC 2061199: Experimental Crystal Structure Determination

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research product

CCDC 1519436: Experimental Crystal Structure Determination

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research product

CCDC 1040205: Experimental Crystal Structure Determination

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research product

CCDC 882324: Experimental Crystal Structure Determination

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research product

CCDC 1832297: Experimental Crystal Structure Determination

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research product

CCDC 1005276: Experimental Crystal Structure Determination

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research product

CCDC 2061194: Experimental Crystal Structure Determination

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research product

CCDC 967094: Experimental Crystal Structure Determination

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research product

CCDC 922455: Experimental Crystal Structure Determination

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research product

CCDC 2061185: Experimental Crystal Structure Determination

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research product

CCDC 1555955: Experimental Crystal Structure Determination

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research product

CCDC 2061204: Experimental Crystal Structure Determination

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research product

CCDC 1036894: Experimental Crystal Structure Determination

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research product

CCDC 1005289: Experimental Crystal Structure Determination

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research product

CCDC 1577842: Experimental Crystal Structure Determination

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CCDC 2061196: Experimental Crystal Structure Determination

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CCDC 1005270: Experimental Crystal Structure Determination

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CCDC 1005279: Experimental Crystal Structure Determination

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CCDC 1476009: Experimental Crystal Structure Determination

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CCDC 922098: Experimental Crystal Structure Determination

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CCDC 915602: Experimental Crystal Structure Determination

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CCDC 1838268: Experimental Crystal Structure Determination

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CCDC 1846186: Experimental Crystal Structure Determination

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CCDC 2061189: Experimental Crystal Structure Determination

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CCDC 1014210: Experimental Crystal Structure Determination

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CCDC 1935510: Experimental Crystal Structure Determination

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CCDC 915604: Experimental Crystal Structure Determination

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CCDC 1868318: Experimental Crystal Structure Determination

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CCDC 1493409: Experimental Crystal Structure Determination

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CCDC 2061191: Experimental Crystal Structure Determination

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CCDC 1005285: Experimental Crystal Structure Determination

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CCDC 1005284: Experimental Crystal Structure Determination

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CCDC 1005282: Experimental Crystal Structure Determination

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CCDC 1539539: Experimental Crystal Structure Determination

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CCDC 2171082: Experimental Crystal Structure Determination

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CCDC 1422860: Experimental Crystal Structure Determination

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CCDC 2061195: Experimental Crystal Structure Determination

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CCDC 2171085: Experimental Crystal Structure Determination

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CCDC 1005271: Experimental Crystal Structure Determination

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CCDC 1987379: Experimental Crystal Structure Determination

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CCDC 957921: Experimental Crystal Structure Determination

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CCDC 957916: Experimental Crystal Structure Determination

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CCDC 2171083: Experimental Crystal Structure Determination

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CCDC 1868323: Experimental Crystal Structure Determination

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CCDC 1826427: Experimental Crystal Structure Determination

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CCDC 2073308: Experimental Crystal Structure Determination

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CCDC 1572983: Experimental Crystal Structure Determination

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CCDC 967127: Experimental Crystal Structure Determination

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CCDC 1014212: Experimental Crystal Structure Determination

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CCDC 1586984: Experimental Crystal Structure Determination

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CCDC 967130: Experimental Crystal Structure Determination

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CCDC 915599: Experimental Crystal Structure Determination

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CCDC 1838267: Experimental Crystal Structure Determination

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CCDC 1838270: Experimental Crystal Structure Determination

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CCDC 2061188: Experimental Crystal Structure Determination

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CCDC 1838269: Experimental Crystal Structure Determination

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CCDC 2061202: Experimental Crystal Structure Determination

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CCDC 2061187: Experimental Crystal Structure Determination

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CCDC 2061200: Experimental Crystal Structure Determination

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(E)-7-(Pyren-1-yl)hept-6-enoic acid

The title compound, C₂₃H₂₀O₂, is a precursor of a pyrene-based supramolecular element for non-covalent attachment to a carbon nanotube. The asymmetric unit contains three independent molecules. The carboxylic acid group in each of these molecules serves as an intermolecular hydrogen-bond donor and acceptor, generating the commonly observed double O-H...O hydrogen-bond motif in an eight-membered ring. Weaker C-H...O, π π [centroid-centroid distance = 3.968 (4) Å] and C-H...π interactions are also found in the crystal structure. peerReviewed

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2-Methyl-4-phenyl-3,4-dihydroquinazoline

The title compound, C15H14N2, was formed during the lithiation of 2-methylquinazoline with phenyllithium followed by hydrolysis of the intermediate lithium 2-methyl-4-phenyl-4H-quinazolin-3-ide. NMR spectra as well as single-crystal X-ray structural data indicate that the reaction product to have the same structure in chloroform solution as in the crystalline state. The phenyl substituent is twisted out of the plane of the 3,4-dihydroquinazoline ring system by 86.47 (7)°. In the crystal, intermolecular N-HN interactions connect the molecules into infinite chains. peerReviewed

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