(2Z,2′Z,4E,4′E)-4,4′-(Cyclo­hexane-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

Oxonium 2-carb­oxy-3-(2-fur­yl)acrylate

In the title compound, H3O+·C8H5O5 −, neighbouring cations and anions are linked by O—H⋯O hydrogen bonds, forming a one-dimensional chain framework along [001]. The crystal structure is further stabilized by π–π inter­actions, with centroid–centroid distances of 3.734 (3) Å

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

1-(3-Amino-1H-inden-2-yl)ethanone

The title compound, C11H11NO, was synthesized by the reaction of 2-(bromo­meth­yl)benzonitrile and acetyl­acetone in the presence of KOH. In the crystal packing, mol­ecules are linked by inter­molecular N—H⋯O hydrogen bonds into chains running parallel to the b axis. Centrosymmetrically-related chains inter­act further through weak C—H⋯π inter­actions

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

5-p-Tolyl-1H-tetra­zole

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

4-[(2H-Tetra­zol-2-yl)meth­yl]benzonitrile

The title compound, C9H7N5, was synthesized by reaction of 4-(bromomethyl)benzonitrile and 2H-tetrazole in the presence of KOH. The relative orientation of the planar tetra­zole ring and the methyl­benzonitrile moiety is (−)-anti­clinal. The crystal packing is dominated by van der Waals inter­actions