Structure investigations of Schiff bases derived from 3-amino-1H-1,2,4-triazole

The crystal structure of 2,2′-((1E,1′E)-hydrazine-1,2-diylidenebis(methaneylylidene))bis(4-chlorophenol), C14H10Cl2N2O2

C14H10Cl2N2O2, triclinic, P 1 ‾ $P\bar{1}$ (no. 2), a = 6.165(12) Å, b = 7.192(13) Å, c = 7.829(15) Å, α = 74.97(2)°, β = 81.92(2)°, γ = 79.84(2)°, V = 328.3(11) Å3, Z = 1, R gt (F) = 0.0312, wR ref (F 2) = 0.0859, T = 296(2) K.

Crystal structure and Hirshfeld surface analysis of 2-{[(E)-(3-cyclo-butyl-1H-1,2,4-triazol-5-yl)imino]-meth-yl}phenol

The title compound, C13H14N4O, was developed using the reaction of salicyl-aldehyde and 3-amino-5-cyclo-butyl-1,2,4-triazole in ethanol under microwave irradiation. This eco-friendly microwave-promoted method proved to be efficient in the synthesis of 2-{[(E)-(3-cyclo-butyl-1H-1,2,4-triazol-5-yl)imino]-meth-yl}phenol in good yields and purity. The title compound is a Schiff base that exists in the phenol-imine tautomeric form and adopts an E configuration. The three independent mol-ecules in the asymmetric unit (A, B and C) are not planar, the cyclo-butyl and the phenol-imine rings are twisted to each other making a dihedral angle of 67.8 (4)° in mol-ecule A, 69.1 (2)° in mol-ecule B and 89.1 (2)° in mol-ecule C. In each mol-ecule an intra-molecular O-H⋯N hydrogen bond is present, forming an S(6) ring motif. A Hirshfeld surface analysis was performed to investigate the contributions of the different inter-molecular contacts within the supra-molecular structure. The major inter-actions are H⋯H (53%), C⋯H (19%) and N⋯H (17%) for mol-ecule A, H⋯H (50%), N⋯H (20%) and C⋯H (20%) for mol-ecule B and H⋯H (57%), C⋯H (14%) and N⋯H (13%) for mol-ecule C.

N-[(E)-Quinolin-2-ylmethylidene]-1,2,4-triazol-4-amine hemihydrate

The title hemihydrate, C12H9N5·0.5H2O, was isolated from the condensation reaction of quinoline-2-carbaldehyde with 4-amino-4H-1,2,4-triazole. The Schiff base molecule adopts an E configuration about the C=N bond and is approximately planar, with a dihedral angle between the quinoline ring system and the 1,2,4-triazole ring of 12.2 (1)°. In the crystal, one water molecule bridges two Schiff base molecules via O—H...N hydrogen bonds. The Schiff base molecules are interconnected by π–π stacking interactions [centroid-centroid distances of 3.7486 (7) and 3.9003 (7) Å] into columns along [1\overline{1}0].