Experimental and Theoretical Biological Probing of Schiff Bases as Esterase Inhibitors: Structural, Spectral and Molecular Insights.

The present study was designed to evaluate the in vitro and in silico potential of the Schiff bases ()-4-ethoxy--((5-nitrothiophen-2-yl)methylene)benzenamine () and ()-2,4-diiodo-6-((2-methyl-3-nitrophenylimino)methyl)phenol (). These Schiff bases were synthesized according to a reported method using ethanol as a solvent, and each reaction was monitored on a TLC until completion of the reaction. The structures of both compounds were elucidated using spectroscopic techniques such as UV-Vis, FTIR, H NMR and C NMR.

Crystal structure and Hirshfeld surface analysis of ()-2-{[(2-iodo-phen-yl)imino]-meth-yl}-6-methyl-phenol.

The title compound, CHINO, was synthesized by condensation of 2-hy-droxy-3-methyl-benzaldehyde and 2-iodo-aniline, and crystallizes in the ortho-rhom-bic space group 222. The 2-iodo-phenyl and benzene rings are twisted with respect to each other, making a dihedral angle of 31.38 (2)°.

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

The title compound, CHNO, 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 . An intra-molecular O-H⋯N hydrogen bond is present, forming an (6) ring motif and inducing the phenol ring and the Schiff base to be nearly coplanar [C-C-N-C torsion angle of 178.

Synthesis, crystal structure and Hirshfeld surface analysis of 1,7-dimethyl-5a,6,11a,12-tetra-hydro-benzo[]benzo[5,6][1,4]oxazino[2,3-][1,4]oxazine.

Mol-ecules of the title compound, CHNO, occupy special positions on the twofold rotation axes. The heterocyclic ring adopts a slightly twisted envelope conformation with one of the two junction carbon atoms as the flap. The mean planes through the two halves of the mol-ecule form a dihedral angle of 72.

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, CHFNO, crystallizes with one mol-ecule in the asymmetric unit. The configuration of the C=N bond is and there is an intra-molecular O-H⋯N hydrogen bond present, forming an (6) ring motif. The dihedral angle between the mean planes of the phenol and the 4-tri-fluoro-methyl-phenyl rings is 44.

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

In the title compound, CHNO, the configuration of the C=N bond of the Schiff base is , and an intra-molecular O-H⋯N hydrogen bond is observed, forming an intra-molecular (6) ring motif. The phenol ring is inclined by 45.73 (2)° from the plane of the aniline ring.

Crystal structure and Hirshfeld surface analysis of 2-phenyl-1-phenanthro[9,10-]imidazol-3-ium benzoate.

In the title compound, CHN ·CHO , 2-phenyl-1-phenanthro[9,10-]imidazole and benzoic acid form an ion pair complex. The system is consolidated by hydrogen bonds along with π-π inter-actions and N-H⋯π inter-actions between the constituent units. For a better understanding of the crystal structure and inter-molecular inter-actions, a Hirshfeld surface analysis was performed.

Crystal structure, DFT and MEP study of ()-2-{[(3-chloro-phen-yl)imino]-meth-yl}-6-methyl-phenol.

In the crystal structure of the title compound, CHClNO, the mol-ecules are linked through C-H⋯O hydrogen bonds and C-H⋯π inter-actions, forming chains parallel to the [010] direction. π-π inter-actions and intra-molecular hydrogen bonds are also observed. The mol-ecular geometry of the title compound in the ground state has been calculated using density functional theory at the B3LYP level with the 6-311++G(2,2) basis set.

()-3-{[(2-Bromo-3-methyl-phen-yl)imino]-meth-yl}benzene-1,2-diol: crystal structure and Hirshfeld surface analysis.

The title compound, CHBrNO, was synthesized by the condensation reaction of 2,3-di-hydroxy-benzaldehyde and 2-bromo-3-methyl-aniline. It crystallizes in the centrosymmetric triclinic space group . The configuration about the C=N bond is .

Crystal structure and DFT study of ()-2-chloro-4-{[2-(2,4-di-nitro-phen-yl)hydrazin-1-yl-idene]meth-yl}phenol aceto-nitrile hemisolvate.

The title Schiff base compound, CHClNO·0.5CHCN, crystallizes as an aceto-nitrile hemisolvate; the solvent mol-ecule being located on a twofold rotation axis. The mol-ecule is nearly planar, with a dihedral angle between the two benzene rings of 3.

()-3-({[3-Meth-oxy-5-(tri-fluoro-meth-yl)phen-yl]imino}meth-yl)benzene-1,2-diol.

The title compound, CHFNO, crystallizes with one mol-ecule in the asymmetric unit. The mean planes of the two phenyl rings of the Schiff base moiety, bearing the OH groups and the imine group, respectively, are inclined to each other by 4.91 (1)°.

Crystal structure and Hirshfeld surface analysis of a Schiff base: ()-6-[(5-chloro-2-meth-oxy-anilino)methyl-idene]-2-hy-droxy-cyclo-hexa-2,4-dien-1-one.

The title compound, CHClNO, is a Schiff base that exists in the keto-enamine tautomeric form and adopts a configuration. In the crystal, the dihedral angle between the planes of the benzene rings is 5.34 (15)°.

Crystal structure of 2-{[(5-nitro-thio-phen-2-yl)methyl-idene]amino}-phenol.

The title compound, C11H8N2O3S, is roughly planar; the di-hedral angle between the planes of the thio-phene and benzene rings is 8.38 (10)°. An intra-molecular O-H⋯N hydrogen bond generates an S(5) ring motif.