Crystal structure and DFT study of (E)-2,6-di-tert-butyl-4-{[2-(pyridin-2-yl)hydrazin-1-yl-idene)meth-yl}phenol.

The title compound, C20H27N3O, was synthesized by condensation reaction of 3,5-di-tert-butyl-4-hy-droxy-benzaldehyde and 2-hydrazinyl-pyridine, and crystallizes in the centrosymmetric monoclinic space group C2/c. The conformation about the C=N bond is E. The dihedral angle between the rings is 18.1 (3)°. An inter-molecular N-H⋯N hydrogen bond generates an R22(8) ring motif. In the crystal, N-H⋯N hydrogen bonds connect pairs of mol-ecules, forming dimers. Density functional theory (DFT) optimized structures at the B3LYP/6-311 G(d,p) level are compared with the experimentally determined mol-ecular structure in the solid state.

Crystal structure of 4,4'-di-nitro-[1,1'-biphen-yl]-2-amine.

In the title biphenyl derivative, C12H9N3O4, the dihedral angle between the benzene rings is 52.84 (10)°. The nitro group attached to the benzene ring is inclined to the ring by 4.03 (2)°, while the nitro group attached to the amino-substituted benzene ring is inclined to the ring by 8.84 (2)°. In the crystal, mol-ecules are linked by two pairs of N-H⋯O hydrogen bonds, forming chains propagating along [101]. Within the chains, these N-H⋯O hydrogen bonds result in the formation of R22(20) and R22(14) ring motifs. The latter ring motif is reinforced by a pair of C-H⋯O hydrogen bonds, enclosing R21(6) ring motifs. The chains are linked by a second C-H⋯O hydrogen bond, forming a three-dimensional supra-molecular structure.