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

The title compound, C15H14N2O3, was prepared by condensation of 2-hy-droxy-5-methyl-benzaldehyde and 2-methyl-3-nitro-phenyl-amine in ethanol. The configuration of the C=N bond is E. An intra-molecular O-H⋯N hydrogen bond is present, forming an S(6) ring motif and inducing the phenol ring and the Schiff base to be nearly coplanar [C-C-N-C torsion angle of 178.53 (13)°]. In the crystal, mol-ecules are linked by C-H⋯O inter-actions, forming chains along the b-axis direction. The Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H⋯H (37.2%), C⋯H (30.7%) and O⋯H (24.9%) inter-actions. The gas phase density functional theory (DFT) optimized structure at the B3LYP/ 6-311 G(d,p) level is compared to the experimentally determined mol-ecular structure in the solid state. The HOMO-LUMO behaviour was elucidated to determine the energy gap.

Crystal structure, Hirshfeld surface analysis and DFT studies of 2-[(2-hy-droxy-5-methyl-benzyl-idene)amino]-benzo-nitrile.

The title compound, C15H12N2O, was synthesized by condensation reaction of 2-hy-droxy-5-methyl-benzaldehyde and 2-amino-benzo-nitrile, and crystallizes in the ortho-rhom-bic space group Pbca. The phenol ring is inclined to the benzo-nitrile ring by 25.65 (3)°. The configuration about the C=N bond is E, stabilized by a strong intra-molecular O-H⋯N hydrogen bond that forms an S(6) ring motif. In the crystal, C-H⋯O and C-H⋯N inter-actions lead to the formation of sheets perpendicular to the a axis. C-H⋯π inter-actions, forming polymeric chains along the a-axis direction, connect these sheets into a three-dimensional network. A Hirshfeld surface analysis indicates that the most important contributions for the packing arrangement are from H⋯H and C⋯H/H⋯C 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 given.

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 4-methyl-2-({[4-(tri-fluoro-meth-yl)phen-yl]imino}-meth-yl)phenol.

The title compound, C15H12F3NO, crystallizes with one mol-ecule in the asymmetric unit. The configuration of the C=N bond is E and there is an intra-molecular O-H⋯N hydrogen bond present, forming an S(6) ring motif. The dihedral angle between the mean planes of the phenol and the 4-tri-fluoro-methyl-phenyl rings is 44.77 (3)°. In the crystal, mol-ecules are linked by C-H⋯O inter-actions, forming polymeric chains extending along the a-axis direction. The Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from C⋯H/H⋯C (29.2%), H⋯H (28.6%), F⋯H/H⋯F (25.6%), O⋯H/H⋯O (5.7%) and F⋯F (4.6%) 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 in the solid state. The HOMO-LUMO behaviour was elucidated to determine the energy gap. The crystal studied was refined as an inversion twin.

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 (Z)-6-[(2-hy-droxy-4-methyl-anilino)-methyl-idene]-4-methyl-cyclo-hexa-2,4-dien-1-one.

The title compound, C15H15NO2, is a Schiff base that exists in the keto-enamine tautomeric form and adopts a Z configuration. The mol-ecule is almost planar, with the two phenyl rings twisted relative to each other by 9.60 (18)°. There is an intra-molecular N-H⋯O hydrogen bond present forming an S(6) ring motif. In the crystal, pairs of O-H⋯O hydrogen bonds link adjacent mol-ecules into inversion dimers with an R 2 2(18) ring motif. The dimers are linked by very weak π-π inter-actions, forming layers parallel to (01). Hirshfeld surface analysis, two-dimensional fingerprint plots and the mol-ecular electrostatic potential surfaces were used to analyse the inter-molecular inter-actions, indicating that the most important contributions for the crystal packing are from H⋯H (55.2%), C⋯H/H⋯C (22.3%) and O⋯H/H⋯O (13.6%) inter-actions.

Crystal structure and Hirshfeld surface analysis of (Z)-6-[(2-hy-droxy-5-nitro-anilino)methyl-idene]-4-methyl-cyclo-hexa-2,4-dien-1-one.

The title compound, C14H12N2O4, is a Schiff base that exists in the keto-enamine tautomeric form and adopts a Z configuration. The mol-ecule is almost planar, the rings making a dihedral angle of 4.99 (7)°. The mol-ecular structure is stabilized by an intra-molecular N-H⋯O hydrogen bond forming an S(6) ring motif. In the crystal, inversion-related mol-ecules are linked by pairs of O-H⋯O hydrogen bonds, forming dimers with an R 2 2(18) ring motif. The dimers are linked by pairs of C-H⋯O contacts with an R 2 2(10) ring motif, forming ribbons extended along the [20] direction. Hirshfeld surface analysis, two-dimensional fingerprint plots and the mol-ecular electrostatic potential surfaces were used to analyse the inter-molecular inter-actions present in the crystal, indicating that the most important contributions for the crystal packing are from H⋯H (33.9%), O⋯H/H⋯O (29.8%) and C⋯H/H⋯C (17.3%) inter-actions.