Search results for "Crystal engineering"
showing 10 items of 68 documents
Copper(II)-methylmalonate complexes with unidentate N-donor ligands: Syntheses, structural characterization and magnetic properties
2009
Abstract Two new methylmalonate-bridged copper(II) complexes with the formulas [Cu(3-Ipy)(Memal)(H 2 O)] ( 1 ) and [Cu(2,4′-bpy)(Memal)(H 2 O)] · 3H 2 O ( 2 ) [Memal = methylmalonate dianion, 3-Ipy = 3-iodopyridine, 2,4′-bpy = 2,4′-bipyridine] have been synthesized and characterized by X-ray diffraction. Both compounds crystallize in the monoclinic space group P 2 1 / n and Z = 4, with unit cell parameters a = 8.5874(13) A, b = 7.1738(14) A, c = 19.093(5) A, β = 99.509(15)° in 1 and a = 17.375(4) A, b = 7.3305(14) A, c = 14.247(3) A, β = 111.409(15)° in 2 . The structures of 1 and 2 consist of zigzag chains of anti-syn carboxylate-bridged copper(II) ions running along the b directi…
Nuclearity controlled cyanide-bridged bimetallic CrIII-MnII compounds: synthesis, crystal structures, magnetic properties and theoretical calculation…
2004
The preparation, X-ray crystallography and magnetic investigation of the compounds PPh4[Cr(bipy)(CN)4].2 CH3CN.H2O (1) (mononuclear), [[Cr(bipy)(CN)4]2Mn-(H2O)4].4H2O (2) (trinuclear), [[Cr(bipy)(CN)4]2Mn(H2O)2] (3) (chain) and [[Cr(bipy)(CN)4]2Mn(H2O)].H2O.CH3CN (4) (double chain) [bipy=2,2'-bipyridine; PPh4 (+)=tetraphenylphosphonium] are described herein. The [Cr(bipy)(CN)4]- unit act either as a monodentate (2) or bis-monodentate (3) ligand toward the manganese atom through one (2) or two (3) of its four cyanide groups. The manganese atom is six-coordinate with two (2) or four (3) cyanide nitrogens and four (2) or two (3) water molecules building a distorted octahedral environment. In 4…
Copper(II)-phenylmalonate complexes with the bifunctional ligands nicotinamide and isonicotinamide
2011
Abstract The use as coligands of the nicotinamide (nia) and isonicotinamide (inia) molecules in the complex formation between copper(II) and phenylmalonate [Phmal = dianion of phenylmalonic acid] yielded the compounds of formula [Cu(inia)(Phmal)(H2O)] (1) and [Cu(inia)(Phmal)(H2O)]n (2). Although single crystals of 1 of appropriate size were grown, their unresolved twinning and space group ambiguity prevented a satisfactory X-ray structure determination. The crystal structure 2 consists of corrugated layers of copper(II) ions with intralayer carboxylate–phenylmalonate bridges in the anti-syn (equatorial-apical) coordination mode. A water molecule and the isonicotinamide group are coordinate…
Dissecting the packing forces in mixed perfluorocarbon/aromatic co-crystals
2021
We carried out a systematic evaluation of the packing forces in co-crystals featuring monoiodo- and diiodo-perfluoroalkanes and 1,2,4-oxadiazoles through single crystal X-ray diffraction and theoretical analysis. The molecules assemble via a combination of halogen bonding and specific dispersive interactions involving the perfluorinated units. We quantitatively elucidated the nature and strength of such interactions through solid-state calculations and Hirshfeld surface analysis. One of the co-crystals, formed by two monoiodoperfluorodecane molecules, the longest perfluorinated chain ever solved at the atomic level, allowed us to fully highlight the role of fluorous interactions.
Halogen Bonding beyond Crystals in Materials Science
2019
Halogen bonding has recently gained well deserved attention in present-day research for its importance in many fields of supramolecular science and crystal engineering. Although generally overlooked in comprehensive studies in the past, halogen bonding has become an important tool also in the field of materials science. An increased number of scientific reports are published every year where halogen bonding is exploited in soft materials rather than in crystal engineering. Here, we focus on a description of the most exciting contemporary developments in the field of halogen-bonded functional soft materials, assembled using the guiding principles of crystal engineering. We give a particular …
The subtle balance of weak supramolecular interactions: The hierarchy of halogen and hydrogen bonds in haloanilinium and halopyridinium salts
2010
The series of haloanilinium and halopyridinium salts: 4-IPhNH3Cl (1), 4-IPhNH3Br (5), 4-IPhNH3H2PO4 (6), 4-ClPhNH3H2PO4 (8), 3-IPyBnCl (9), 3-IPyHCl (10) and 3-IPyH-5NIPA (3-iodopyridinium 5-nitroisophthalate, 13), where hydrogen or/and halogen bonding represents the most relevant non-covalent interactions, has been prepared and characterized by single crystal X-ray diffraction. This series was further complemented by extracting some relevant crystal structures: 4-BrPhNH3Cl (2, CCDC ref. code TAWRAL), 4-ClPhNH3Cl (3, CURGOL), 4-FPhNH3Cl (4, ANLCLA), 4-BrPhNH3H2PO4, (7, UGISEI), 3-BrPyHCl, (11, CIHBAX) and 3-ClPyHCl, (12, VOQMUJ) from Cambridge Structural Database for sake of comparison. Bas…
Solvent Exchange in Thermally Stable Resorcinarene Nanotubes
2006
The assembly of C-methyl resorcinarene into a tubular supramolecular solid-state structure, its thermal stability, and its hosting properties are reported. Careful control of the crystallisation conditions of C-methyl resorcinarene and 1,4-dimethyl-1,4-diazoniabicyclo[2.2.2]octane (1,4-dimethyl DABCO) dibromide leads to a formation of two crystallographically different, but structurally very similar, solid-state nanotube structures. These structures undergo a remarkable variety of supramolecular interactions, which lead to the formation of 0.5 nm diameter nonpolar tubes through the crystal lattice. The formation of these tubes is templated by suitably sized small alcohols, namely, n-propano…
Monitoring the hydrogen bond net configuration and the dimensionality of aniline and phenyloxamate by adding 1 H -pyrazole and isoxazole as substitue…
2019
This work describes the synthesis and characterization of a new class of oxamic acid derivatives containing pyrazole and isoxazole as substituents to investigate their ability to form hydrogen bonds aiming at applying them in crystal engineering and molecular self-recognition. In this respect, we report a new synthesis of 2-(4-nitrophenyl)-1,3-propanedial (1) in high yield using SOCl2 as a chlorinating agent. The new oxamic esters 4-(1H-pyrazol-4-yl)phenylene-N-(ethyloxamate) (2d) and 4-(1,2-oxazol-4-yl)phenylene-N-(ethyloxamate) (3d) were prepared from 1. The synthetic route consists of the cyclisation of 1 either with hydrazine to afford 4-(-aminophenyl)-1H-pyrazole (2a) or with hydroxyla…
Structural versatility of the malonate ligand as a tool for crystal engineering in the design of molecular magnets
2002
The synthesis of ferro- and ferri-magnetic systems with a tunable Tc and three-dimensional (3-D) ordering from molecular precursors implying transition metal ions is one of the active branches of molecular inorganic chemistry. The nature of the interactions between the transition metal ions (or transition metal ions and radicals) is not so easy to grasp by synthetic chemists working in this field since it may be either electrostatic (orbital) or magnetic (mainly dipolar). Therefore, the systems fulfilling the necessary requirements to present the expected magnetic properties are not so easy to design on paper and realize in the beaker. In this work we show how the design of one-, two- and t…
Synthesis of tetrahalide dianions directed by crystal engineering
2015
CrystEngComm 17(35), 6641-6645(2015). doi:10.1039/C5CE01288K