In the title compound, C(12)H(12)N(2) (2+)·2ClO(4) (-), the dihedral angle between the two outer pyridine rings of the dication is 44.8 (1)°. In the crystal, weak intermolecular C-H⋯O hydrogen bonds occur.

The characteristics of N--H...O, O--H...O, and C--H...O hydrogen bonds and other weak intermolecular interactions are analyzed in a large and diverse group of 251 protein-ligand complexes using a new computer program that was developed in-house for this purpose. The interactions examined in the present study are those which occur in the active sites, defined here as a sphere of 10 A radius arou...

The asymmetric unit of the title compound, C(8)H(9)Cl(2)NO, contains two crystallographically independent mol-ecules which are connected via an N-H⋯O hydrogen bond . There is aromatic π-π stacking in the crystal, with a centroid-centroid distance between benzene rings of 3.48 (2)Å. The crystal packing is stabilized by intermolecular hydrogen bonds.

The title compound, C(9)H(8)N(2)O(8), was obtained by the reaction of imidazole-4,5-dicarb-oxy-lic acid and 2-chloro-acetic acid. An intra-molecular O-H⋯O hydrogen bond occurs. The crystal packing is stabilized by intermolecular O-H⋯O and C-H⋯O hydrogen bonds, which link mol-ecules into a three-dimensional network.

In the title compound, C(11)H(11)NO(4), the asymmetric unit contains two unique mol-ecules, both of which are almost planar, with r.m.s. deviations of 0.047 and 0.059 Å. The dihedral angles between the benzene ring and the plane of maleamic acid unit are 3.43 (5) and 5.79 (3)° in the two mol-ecules. The mol-ecular structures are stabilized by a short intra-molecular O-H⋯O hydrogen bond within e...

Four series of hydrogen bonded complexes of formamide and substituted benzoic acids and benzoates were studied in the light of substituent effect on intermolecular interactions. The analysis based on energy of interaction, geometry, QTAIM-derived properties of hydrogen bond critical point and energy of hydrogen bonds were made and discussed. The opposite effect of the substituent on hydrogen bo...

In the title compound, C(25)H(22)Cl(2)N(2)O(4)·CH(3)OH, the macrocyclic mol-ecule adopts a slightly distorted C(2)-symmetric conformation. The macrocyclic mol-ecules are linked via N-H⋯O hydrogen bonds between the amide groups into chains extending along the [010] direction. The methanol mol-ecules bridge these chains via N-H⋯O and O-H⋯O hydrogen bonds with the formation of a two-dimensional po...

Chitosan and poly(methyl methacrylate) (PMMA) composites were synthesized by polymerization with heating mechanochemical method. The obtained polymer analyzed the ATR FT-IR spectroscopy presence of intermolecular hydrogen bonds hydrophobic interactions in formation PMMA chitosan was shown.

The title compound, C(2)H(10)N(2) (2+)·2HC(4)O(4) (-)·H(2)O, a new polymorph of ethyl-enediammonium bis-(hydrogen squarate) monohydrate, was synthesized by slow evaporation of an acid solution. The asymetric unit contains two hydrogen squarate anions, two half-mol-ecules of protonated ethyl-enediamine arranged around a twofold axis and one water mol-ecule. In the crystal, N-H⋯O and O-H⋯O hydrog...

Hydrogen bonds are important in supramolecular chemistry and responsible for proton transfer processes. This manuscript reports new hydrogen-bonding systems of redox-active acid-base assemblies consisting of dimethylthio-tetrathiafulvalene dicarboxylic acid (H(2)L) coupled with pyridine (py), 2,2'-bipyridine (2,2'-bpy), and 4,4'-bipyridine (4,4'-bpy). The (1)H NMR chemical shifts of the pyridin...