Zhi-Rong Qu

5-p-Tolyl-1H-tetra-zole.

The title compound, C8H8N4, possesses crystallographic mirror symmetry, with four C atoms lying on the reflecting plane, which bisects the phenyl and tetrazole rings. It is composed of a planar r.m.s. deviation (0.0012 Å) tetrazole ring which is nearly coplanar with the benzene ring, the dihedral angle being 2.67 (9)°. In the crystal, symmetry-related molecules are linked by intermolecular N—H⋯N hydrogen bonds. The molecules stack along [100] with a π⋯π interaction involving the phenyl and tetrazole rings of adjacent molecules [centroid–centroid distance = 3.5639 (15) Å]. The H atom of the N—H group is disordered over two sites of equal occupancy. The methyl H atoms were modelled as disordered over two sets of sites of equal occupancy rotated by 60° with respect to each other.

Dimethyl 1-cyano­methyl-1H-pyrazole-3,5-dicarboxyl­ate

The title molecule, C9H9N3O4, syhthesized from 1H-pyrazole-3,5-dicarboxylic acid and 2-bromoacetonitrile, is approximately planar; the interplanar angles between the pyrazole ring and the mean planes of the two carboxylate units and the cyanomethyl unit are 4.49 (10), 5.56 (9) and 5.03 (19)°, respectively. In the crystal, inversion dimers linked by pairs of weak C—H ⋯O bonds occur, and the packing is further stabilized by aromatic π–π stacking [centroid–centroid separation = 3.793 (4) Å].

Poly[aqua­[μ3-5-(2-carboxyl­atophen­yl)-1H-tetra­zolato]zinc(II)]

The title coordination polymer, [Zn(C8H4N4O2)(H2O)]n, was prepared by the hydrothermal reaction of zinc nitrate and 2-(1H-tetrazol-5-yl)benzoic acid. Two types of coordinated zinc cations exist in the structure. One is tetrahedrally coordinated by two O and two N from two ligands, the other is octahedrally coordinated by two N and two O from two ligands at equatorial sites and by two O atoms of water molecules at axial sites, resulting in a two-dimensional framework. The crystal structure is stabilized by intramolecular O—H⋯O and O—H⋯N hydrogen bonds.

catena-Poly[cadmium(II)-μ-benzene-1,2-diamine-κ2N:N′-di-μ-chlorido]

The title compound, [CdCl2(C6H8N2)]n, is a coordination polymer prepared by the hydrothermal reaction of cadmium chloride and o-diaminobenzene. The cadmium cation, located on an inversion center, is octahedrally coordinated by four Cl atoms at equatorial sites and two N atoms from two ligands at the axial sites. Cd atoms are bridged by Cl atoms, forming extended chains parallel to [010]. Neighboring chains are connected by N—H⋯Cl hydrogen bonds.

(1Z,1'Z,3E,3'E)-1,1'-Diphenyl-3,3'-[(1S,2S)-cyclo-hexane-1,2-diyldinitrilo]dibut-1-en-1-ol.

A new tetradentate chiral Schiff base ligand, C26H30N2O2, has been synthesized by the reaction of 1-phenylbutane-1,3-dione with (1S,2S)-(−)-1,2-diaminocyclohexane. The chiral centers in the molecule have the same S configuration, since the absolute configuration was determined by that of the starting reagent (1S,2S)-(−)-1,2-diaminohexane. The cyclohexane ring is in a chair conformation, and the substituents are equatorial in the most stable conformation (trans-cyclohexyl). The crystal structure is stabilized by two intramolecular O—H⋯N hydrogen bonds and a weak C—H⋯π interaction.

(2Z,2'Z,4E,4'E)-4,4'-(Cyclo-hexane-1,2-diyldinitrilo)dipent-2-en-2-ol.

A new tetradentate chiral Schiff base ligand, C16H26N2O2, has been synthesized by the reaction of acetylacetone with (1R,2R)-(−)-1,2-diaminocyclohexane. Both of the molecules in the asymmetric unit are of the same chirality (R configuration), since the absolute configuration was determined by the starting reagent (1R,2R)-(−)-1,2-diaminocyclohexane. The six-membered cyclohexane ring is in a chair conformation, and the substituents are equatorial in the most stable conformation (trans-cyclohexyl). At the ring substituents, large conjugated —C=N—CH=C—OH systems exist, resulting from the original ketone converted into the enol form. With H atoms excluded, the atoms of each substituent lie in the same plane. The two molecules in the asymmetric unit have almost the same structure, with slight differences in the torsion angles between the substituents and the cyclohexane ring; the corresponding N1—(C—C—C)cyclohexane torsion angles are −177.2 (3) and 179.3 (4)° in one molecule and −176.5 (3) and 178.4 (4)° in the other. Two intramolecular O—H⋯N hydrogen bonds exist in each molecule.

2-Carboxy-1-(3-nitrophenyl)ethanaminium perchlorate

In the cation of the title compound, C9H11N2O4 +·ClO4 −, the conformation is stabilized by an intramolecular N—H⋯O hydrogen bond. In the crystal packing, centrosymmetrically related cations interact through intermolecular O—H⋯O hydrogen bonds involving the carboxy groups, forming dimers. The dimers and the perchlorate anions are further linked into layers parallel to the ab plane by C—H⋯O and N—H⋯O hydrogen-bonding interactions.

2-(Chloro­meth­yl)benzimidazolium chloride

The structure of title compound, C8H8ClN2 +·Cl−, comprises discrete ions which are interconnected by N—H⋯Cl hydrogen bonds, leading to a neutral one-dimensional network in [001]. This hydrogen bonding appears to complement π–π stacking interactions [centroid–centroid distances 3.768 (2) and 3.551 (2) Å] and helps to stabilize the structure further.

Redetermination of 3-(ammonio-meth-yl)pyridinium dichloride.

The crystal structure of the title compound, C6H10N2 2+·2Cl−, has been reported previously in the non-standard setting P21/a [Genet (1965 ▶). Bull. Soc. Fr. Miner. Crist. 88, 463–470], with an R value of 0.16. The current redetermination improves significantly the precision of the geometric parameters. In the crystal packing, cations and anions are linked by intermolecular N—H⋯Cl and C—H⋯Cl hydrogen bonds into a three-dimensional network.

2-Carb­oxy-1-phenyl­ethanaminium nitrate

In the title salt, C9H12NO2 +·NO3 −, the cation and anion are linked by a bifurcated N—H⋯(O,O) hydrogen bond. The crystal packing is stabilized by intermolecular N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds, which connect neighbouring cations and anions, resulting in a two-dimensional network.