Crystal structure of (E)-9-({[4-(di-ethyl-amino)-phen-yl]imino}-meth-yl)-2,3,6,7-tetra-hydro-1H,5H-pyrido[3,2,1-ij]quinolin-8-ol

Crystal structure, Hirshfeld surface analysis and DFT studies of (E)-2-{[(3-chloro-4-methyl-phen-yl)imino]-meth-yl}-4-methyl-phenol

The title compound, C15H14ClNO, was synthesized by condensation reaction of 2-hy-droxy-5-methyl-benzaldehyde and 3-chloro-4-methyl-aniline, and crystallizes in the monoclinic space group P21/c. The 3-chloro-benzene ring is inclined to the phenol ring by 9.38 (11)°. The configuration about the C=N bond is E and an intra-molecular O-H⋯N hydrogen bond forms an S(6) ring motif. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the packing arrangement are from H⋯H (43.8%) and C⋯H/H⋯C (26.7%) inter-actions. The density functional theory (DFT) optimized structure at the B3LYP/ 6-311 G(d,p) level is compared with the experimentally determined mol-ecular structure and the HOMO-LUMO energy gap is provided.

Crystal structure, Hirshfeld surface analysis and DFT studies of (E)-4-methyl-2-{[(4-methyl-phen-yl)imino]-meth-yl}phenol

In the title compound, C15H15NO, the configuration of the C=N bond of the Schiff base is E, and an intra-molecular O-H⋯N hydrogen bond is observed, forming an intra-molecular S(6) ring motif. The phenol ring is inclined by 45.73 (2)° from the plane of the aniline ring. In the crystal, mol-ecules are linked along the b axis by O-H⋯N and C-H⋯O hydrogen bonds, forming polymeric chains. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the packing arrangement are from H⋯H (56.9%) and H⋯C/C⋯H (31.2%) inter-actions. The density functional theory (DFT) optimized structure at the B3LYP/ 6-311 G(d,p) level is compared with the experimentally determined mol-ecular structure, and the HOMO-LUMO energy gap is provided. The crystal studied was refined as an inversion twin.

Crystal structure and Hirshfeld surface analysis of 2-{[(4-iodo-phen-yl)imino]-meth-yl}-4-nitro-phenol

The title compound, C13H9IN2O3, was synthesized by a condensation reaction between 2-hy-droxy-5-nitro-benzaldehyde and 4-iodo-aniline, and crystallizes in the ortho-rhom-bic space group Pna21. The 4-iodo-benzene ring is inclined to the phenol ring by a dihedral angle of 39.1 (2)°. The configuration about the C=N double bond is E. The crystal structure features C-H⋯O hydrogen-bonding inter-actions. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the packing arrangement are O⋯H/H⋯O (26.9%) and H⋯H (22.0%) inter-actions.

Crystal structure of 4-[(3-meth-oxy-2-oxidobenzyl-idene)azaniumyl]-benzoic acid methanol monosolvate

In the crystal of the title compound, C15H13NO4·CH3OH, the Schiff base mol-ecule exists in the zwitterionic form; an intra-molecular N-H⋯O hydrogen bond stabilizes the mol-ecular structure. The benzene rings are nearly co-planar, subtending a dihedral angle of 5.34 (2)°. In the crystal, classical O-H⋯O and weak C-H⋯O hydrogen bonds link the Schiff base mol-ecules and methanol solvent mol-ecules into a three-dimensional supra-molecular architecture. The crystal studied was refined as an inversion twin.

Crystal structure and DFT study of 8-hy-droxy-1,2,3,5,6,7-hexa-hydro-pyrido[3,2,1-ij]quinoline-9-carbaldehyde

In the title compound, C13H15NO2, the fused non-aromatic rings of the julolidine moiety adopt envelope conformations. The hy-droxy group forms an intra-molecular hydrogen bond to the aldehyde O atom, generating an S(6) ring motif. Weak inter-molecular C-H⋯O hydrogen bonds help to stabilize the crystal structure. 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.