Search results for "Hydrogen Bonds"
showing 10 items of 82 documents
Identification and H(D)-bond energies of C-H(D)Cl interactions in chloride-haloalkane clusters: a combined X-ray crystallographic, spectroscopic, and…
2016
The cationic (1,3,5-triazapentadiene)Pt(II) complex [Pt{NH[double bond, length as m-dash]C(N(CH2)5)N(Ph)C(NH2)[double bond, length as m-dash]NPh}2]Cl2 ([]Cl2) was crystallized from four haloalkane solvents giving [][Cl2(CDCl3)4], [][Cl2(CHBr3)4], [][Cl2(CH2Cl2)2], and [][Cl2(C2H4Cl2)2] solvates that were studied by X-ray diffraction. In the crystal structures of [][Cl2(CDCl3)4] and [][Cl2(CHBr3)4], the Cl(-) ion interacts with two haloform molecules via C-DCl(-) and C-HCl(-) contacts, thus forming the negatively charged isostructural clusters [Cl(CDCl3)2](-) and [Cl(CHBr3)2](-). In the structures of [][Cl2(CH2Cl2)2] and [][Cl2(C2H4Cl2)2], cations [](2+) are linked to a 3D-network by a syste…
Energetic study of bifurcated hydrogen bonds in secondary structures of salts composed with dicarboxylic acids and ethylamine
2020
Abstract The nature of bifurcated hydrogen bonds prompted us to analyze the energy of supramolecular motifs on the example of new structures of carboxylic acids salts with amines, which guarantee a multitude of such interactions. Experimental and theoretical studies of four dicarboxylic salts with primary amine: ethylammonium succinate hydrate (1), tartrate hydrate (2) phthalate hydrate (3) and terephthalate (4) has been investigated along with study of the strength of interactions between the anions and cations. The complete topological analysis of the charge density for all new structures allowed designation of the estimated Cumulative Dissociation Energy (eCDE).
Synthesis, Structure and Anion Sensing Properties of a Dicationic Bis(imidazolium)-Based Cyclophane
2018
The preparation and sensing properties of a tetracyclic cyclophane receptor containing two imidazolium rings as anion binding sites and two fluorene rings as fluorescent signaling units, are reported. The receptor behaves as a selective fluorescent chemosensor molecule for inorganic phosphates. H-NMR spectroscopical data clearly indicate the simultaneous occurrence of charge-assisted aromatic and aliphatic C−H noncovalent interactions. PCM/DFT calculations have been carried out to predict the structures of the complexes formed with one and two molecules of PF , HPO and HPO .
Anion Recognition by a Bioactive Diureidodecalin Anionophore: Solid-State, Solution, and Computational Studies
2018
Recent work has identified a bis-(p-nitrophenyl)ureidodecalin anion carrier as a promising candidate for biomedical applications, showing good activity for chloride transport in cells yet almost no cytotoxicity. To underpin further development of this and related compounds, a detailed structural and binding investigation is reported. Crystal structures of the transporter as five solvates confirm the diaxial positioning of urea groups while revealing a degree of conformational flexibility. Structures of complexes with Cl−, Br−, NO3 −, SO4 2− and AcO−, supported by computational studies, show how the binding site can adapt to accommodate these anions. 1H NMR binding studies revealed exception…
Structure of chloroantimonates(III) with an imidazolium cation: (C3H5N2)[SbCl4] and (C3H5N2)2[SbCl5]
2003
Abstract Two different chloroantimonates(III) with an imidazolium cation have been synthesized by the reaction of antimony trichloride and imidazole in an aqueous solution of hydrochloric acid. The crystals of (C3H5N2)[SbCl4] are monoclinic, space group C2/c, while (C3H5N2)2[SbCl5] crystallizes in the orthorhombic system, space group Pbcn. Both crystals are built of one dimensional zig-zag chains composed of [SbCl6]3− octahedra connected by edges and corners, respectively. The cavities between inorganic chains are filled by imidazolium cations. In both structures, one crystallographically independent imidazolium cation is rotationally disordered, and the positions of all atoms are split bet…
N-Alkyl Ammonium Resorcinarene Chloride Receptors for Guest Binding in Aqueous Environment
2016
Host systems with guest binding ability in water and/or biological fluids are a current challenge in supramolecular host–guest chemistry. Here we present the first syntheses of water-soluble N-ethanol ammonium resorcinarene chlorides (NARCls) with terminal hydroxyl groups at the upper rim. The NARCls possess deep cavities and are shown to bind a variety of guest molecules such as linear and cyclic alkanes, linear halogenated alkanes, and aromatic fluorophores (naphthalene, p-(phenylazo)phenol) in water through hydrophobic interactions, as well as 1,4-dioxane (a water soluble guest) via hydrogen bonds. The receptors are monomeric in aqueous media and form 1:1 host–guest complexes with bindin…
A Halogen-Bonded Dimeric Resorcinarene Capsule.
2015
Iodine (I2) acts as a bifunctional halogen-bond donor connecting two macrocyclic molecules of the bowl-shaped halogen-bond acceptor, N-cyclohexyl ammonium resorcinarene chloride 1, to form the dimeric capsule [(1,4-dioxane)3@1(2)(I2)2]. The dimeric capsule is constructed solely through halogen bonds and has a single cavity (V=511 Å(3)) large enough to encapsulate three 1,4-dioxane guest molecules.
Muscimol hydration and vibrational spectroscopy – The impact of explicit and implicit water
2022
The presented study focuses on the interaction of the well-known neurotoxin muscimol with water. Two approaches for the water solvent are applied – the explicit and the implicit. The muscimol-water clusters were obtained by the molecular dynamics simulations and the first solvation shell was kept for further studies. Implicit water was mimicked via the polarized continuum model (PCM). All three tautomeric forms of the free muscimol molecule are considered in the calculations. The combined theoretical and experimental vibrational IR and Raman studies determined the stability of the prevailing zwitterion form in water. We proved that water molecules in the first solvation shell are crucial fo…
Crystal structure and Hirshfeld surface analysis of (E)-4-chloro-N-{2-[2-(4-nitrobenzylidene)hydrazin-1-yl]-2-oxoethyl}benzenesulfonamide N,N-di…
2018
Reaction of N-(4-chlorobenzenesulfonyl)glycinyl hydrazide with 4-nitrobenzaldehyde gives the N,N-dimethylformamide monosolvated N-acylhydrazone derivative, (E)-N-{2-[2-(4-nitrobenzylidene)- hydrazine-1-yl]-2-oxoethyl}-4-χhlorobenzenesulfonamide. Rings of (10) and (11) graph-set motifs are formed in the crystal structure by N—H⋯O and C—H⋯O hydrogen bonds. The two-dimensional fingerprint (FP) plots for significant intermolecular interactions indicate that the greatest contribution is from the O⋯H/H⋯O contacts (31.3%), corresponding to N⋯H⋯O/C⋯H⋯O interactions.
A Bipyridine‐Palladium Derivative as General Pre‐Catalyst for Cross‐Coupling Reactions in Deep Eutectic Solvents
2019
A versatile and DES‐compatible bipyridine palladium complex has been developed as a general pre‐catalyst for different cross‐coupling reactions (Hiyama, Suzuki‐Miyaura, Heck‐Mizoroki and Sonogashira) in deep eutectic solvents. Hydrogen bond capacity of the ligand allows to keep the excellent level of results previously obtained in classical organic solvents. Palladium pre‐catalyst showed a high catalytic activity for many cross‐coupling reactions, demonstrating a great versatility and applicability. Also, this methodology employs sustainable solvents as a reaction medium and highlights the potential of DES as alternative solvents in organometallic catalysis. The catalyst and DES were easily…