Block-localized wave function (BLW) method, which is a variant of the ab initio valence bond (VB) theory, was employed to explore the nature of resonance-assisted hydrogen bonds (RAHBs) and to investigate the mechanism of synergistic interplay between pi delocalization and hydrogen-bonding interactions. We examined the dimers of formic acid, formamide, 4-pyrimidinone, 2-pyridinone, 2-hydroxpyri...

A salt with the composition [C12H9N2][C8H3Cl2O4] (1) with 4,5-dichlorophthalic acid and 1,10phenanthroline (phen) has been synthesized and characterized by IR, UV spectroscopy, elemental analysis, and X-ray crystallography. Compound 1 represents a 3D chiral supramolecular framework containing monohelical chains (21 axis) through multiform C–H· · ·O, O–H· · ·O, N–H· · ·N intramolecular hydrogen ...

In the title compound, C(14)H(18)N(2)O(3)S, the 1H-pyrazole ring is approximately planar, with a maximum deviation of 0.005 (1) Å. The dihedral angle formed between the 1H-pyrazole and phenyl rings is 79.09 (5)°. Pairs of inter-molecular N-H⋯O and O⋯H⋯N hydrogen bonds form dimers between neighboring mol-ecules, generating R(2) (2)(10) ring motifs. These dimers are further linked by intermolecul...

The title compound, [Cu2(C6)H12N4O2)(ClO4)2(C11H6N2O)2].-2C11H6N2O, contains a dinuclear copper(II) complex which lies about a twofold axis at the mid-point of the C-C bond of the oxamide ligand that bridges the two Cu(II) atoms. The Cu...Cu distance is 5.215 (2) A and the Cu atoms have distorted octahedral coordination geometry. Intramolecular N-H...O and N-H...N hydrogen bonds and intermolecu...

The title compound, C(10)H(12)N(2)O(4), adopts a trans configuration with respect to the C=N double bond. The non-H atoms of the mol-ecule are essentially coplanar, with a maximum deviation of 0.015 (2) Å. An intra-molecular O-H⋯N inter-action is observed. In the crystal structure, the mol-ecules are linked into a two-dimensional network parallel to the ac plane by N-H⋯O hydrogen bonds involvin...

In the tricyclic nucleoside 7-( -d-ribofuranosyl)-7H-imidazo[1,2-c]pyrazolo[4,3-e][1,2,3]triazine, C11H12N6O4, the conformation of the N-glycosyl bond is intermediate between anti and high anti [ = ÿ103.5 (3) ]. The ribofuranose moiety adopts a 3T 2 sugar pucker (S-type sugar) and the conformation at the exocyclic CÐC bond is ap (gauche±trans). Molecules of the title compound form a three-dimen...

In the title compound, C(24)H(22)N(4)O(2)S(2), the dihedral angles formed by the thio-ureido groups with the attached benzene ring are 43.81 (13) and 75.25 (13)°. The dihedral angle between the thio-ureido groups is 85.48 (10)°. The mol-ecule is stabilized by intra-molecular N-H⋯S, N-H⋯O and C-H⋯S hydrogen bonds. In the crystal, molecules are linked by intermolecular N-H⋯S hydrogen bonds togeth...

The title compound, C(19)H(16)N(4)O(2)·0.425CH(4)O, crystallizes with two formula units per asymmetric unit. Researching its crystal structure constitutes part of a study of the nature of inter-actions between the N(+)-O(-) group and the vicinal NH group. The nitrone group and methanol solvent mol-ecules are linked via four N-H⋯O and one O-H⋯O hydrogen bonds, with donor-acceptor distances of 2....

The conformation of dimethyl (R,R)-tartrate has been analyzed on the basis of the single crystal X-ray diffraction method as well as by ab-initio quantum chemical studies. The results showed that the extended T conformation containing two planar hydroxyester moieties predominates in both ab-initio and X-ray studies. The lowest energy conformer in ab-initio calculations has C2 symmetry and hydro...

Hydrogen and halogen bonds are important anisotropic attractive interactions in the molecular crystalline state. 2,6-dibromophenol (1) was analyzed by single-crystal X-ray diffraction for first time. The intermolecular interaction pattern studied Hirshfeld surface analysis along with 2D fingerprint diagrams. characteristic that dominate crystal packing electrostatic type-II Br⋅⋅⋅Br interactions...