Crystal structure and computational study of 2,4-di-chloro-N-[(E)-(5-nitro-thio-phen-2-yl)methyl-idene]aniline.

The title compound, C11H6Cl2N2O2S, is a Schiff base that incorporates an N-bound 2,4-di-chloro-phenyl and a C-bound 5-nitro-thio-phene ring. The mol-ecule is approximately planar, the maximum deviation from the mean plane being 0.233 (4) Šfor the C=N N atom. The dihedral angle between the benzene and thio-phene rings is 9.7 (2)°. The C=N double bond has an E configuration. The crystal structure features C-H⋯O hydrogen bonds,forming sheets parallel to (10-1), and π-π stacking inter-actions between symmetry-related thio-phene and benzene rings, in which the distance between adjacent ring centroids is 3.707 (4) Å, forming a three-dimensional supramolecular structure. Geometric parameters from quantum-chemical calculations are in good agreement with experimental X-ray diffraction results.

Crystal structure, spectroscopic studies and quantum mechanical calculations of 2-[((3-iodo-4-methyl)phenylimino)methyl]-5-nitrothiophene.

The title compound, 2-[((3-iodo-4-methyl)phenylimino)methyl]-5-nitrothiophene, C12H9O2N2I1S1, was synthesized and characterized by IR, UV-Vis and single-crystal X-ray diffraction technique. The molecular structure was optimized at the B3LYP, B3PW91 and PBEPBE levels of the density functional method (DFT) with the 6-311G+(d,p) basis set. Using the TD-DFT method, the electronic absorption spectra of the title compound was computed in both the gas phase and ethanol solvent. The harmonic vibrational frequencies of the title compound were calculated using the same methods with the 6-311G+(d,p) basis set. The calculated results were compared with the experimental determination results of the compound. The energetic behavior such as the total energy, atomic charges, dipole moment of the title compound in solvent media were examined using the B3LYP, B3PW91 and PBEPBE methods with the 6-311G+(d,p) basis set by applying the Onsager and the polarizable continuum model (PCM). The molecular orbitals (FMOs) analysis, the molecular electrostatic potential map (MEP) and the nonlinear optical properties (NLO) for the title compound were obtained with the same levels of theory. And then thermodynamic properties for the title compound were obtained using the same methods with the 6-311G(d,p) basis set.

(E)-1-[(3-Iodo-phen-yl)imino-meth-yl]naphthalen-2-ol.

In the title mol-ecule, C(17)H(12)INO, the dihedral angle between the naphthaldeyde plane and the 3-iodo-aniline plane is20.07 (13)°. It exists in the solid state as an enol-imine tautomer with a strong intra-molecular O-H⋯N hydrogen bond.

4-Meth-oxy-N-[(E)-(5-nitro-thio-phen-2-yl)methyl-idene]aniline.

The title mol-ecule, C(12)H(10)N(2)O(3)S, is nonplanar with an inter-planar angle of 33.44 (7)° between the benzene and thio-phene rings. In the crystal there exist only weak inter-molecular C-H⋯O inter-actions, π-π inter-actions between the benzene rings [centroid-centroid distance = 3.7465 (14) Å] and X-Y⋯π inter-actions to the thio-phene and benzene rings [N⋯centroid distances = 3.718 (3) and 3.355 (3) Å, respectively]. Inter-molecular C-H⋯O inter-actions link the mol-ecules into chains parallel to the a axis.

2-Methyl-3-nitro-N-{(E)-[5-(4-nitro-phen-yl)furan-2-yl]methyl-idene}aniline.

In the title Schiff-base type compound, C(18)H(13)N(3)O(5), the central furan ring makes dihedral angles of 12.80 (7) and 51.43 (4)° with the terminal benzene rings. The dihedral angle between the benzene rings is 45.43 (3)°. In the crystal, C-H⋯O hydrogen bonds link the mol-ecules into layers parallel to (010). In addition, there are π-π stacking inter-actions within the layer [centroid-centroid distance = 3.584 (1) Å] and between the layers [centroid-centroid distance 3.751 (1) Å].

(E)-1-[(3-Bromo-phen-yl)imino-meth-yl]naphthalen-2-ol.

The title compound, C(17)H(12)BrNO, exists in an enol-imine form and the mol-ecular structure features an intra-molecular O-H⋯N hydrogen bond. The dihedral angle between the benzene ring and the naphthalene ring system is 17.27 (15)°.

2-(2-Fluoro-4-hy-droxy-benz-yl)isoindoline-1,3-dione.

In the title compound, C(15)H(10)FNO(3), the dihedral angle between the isoindoline-1,3-dione and 3-fluoro-4-methyl-phenol groups is 86.88 (8)°. The isoindoline-1,3-dione fragment is almost planar, with an r.m.s. deviation of 0.0154 Šwithin the group. Inter-molecular C-H⋯O hydrogen bonds generate C(6) chains running parallel to the [010] direction.

(Z)-2-[(E)-2-(1-Benzothio-phen-3-yl-methyl-idene)hydrazin-1-yl-idene]-1,2-diphenyl-ethanone.

The title compound, C(23)H(16)N(2)OS, is not planar, the phenyl ring of the benzoyl group making a dihedral of 77.61 (7)° with the benzothio-phene system ring. The benzothio-phene system and the remaining phenyl ring make an angle of 12.71 (13)°. The conformation around the imine functions is E for the C=N bond towards the benzothio-phene system and Z for the C=N bond towards the benzoyl group. The packing of the mol-ecules shows C-H⋯π inter-actions. A weak intramolecular C-H⋯N bond also occurs.

(E)-3-chloro-N-((5-nitrothiophen-2-yl)methylene)aniline: a combined crystallographic, theoretical and antimicrobial activity investigation.

The title molecule, (E)-3-chloro-N-((5-nitrothiophen-2-yl)methylene)aniline, (C(11)H(7)ClN(2)O(2)S), was synthesized and characterized by IR and single-crystal X-ray structure determination. The compound crystallizes in the monoclinic space group P2(1)/c. In addition, the molecular geometry, vibrational frequencies and frontier molecular orbitals analysis of the title compound in the ground state have been calculated by using the PM3 semi-empirical, HF/6-31G(d) and B3LYP/6-31G(d) ab initio methods. The results of the optimized molecular structure are exhibited and compared with the experimental X-ray diffraction and the calculated results are show that the optimized geometry can well reproduce the crystal structure. The Schiff base compounds are very important in medicinal and pharmaceutical fields because of their wide spectrum of biological activities. Most of them show biological activities such as antimicrobial, antifungal as well as antitumor activity. Therefore, (C(11)H(7)ClN(2)O(2)S) was investigated for their antimicrobial activities, Gram-positive and Gram-negative bacteria.

(E)-4-Methyl-N-[(5-nitro-thio-phen-2-yl)methyl-idene]aniline.

In the crystal structure of the title compound, C(12)H(10)N(2)O(2)S, the benzene and the 2-nitro-thio-phene rings make a dihedral angle of 7.47 (12)°. The dihedral angle between the nitro group and the attached ring is 1.9 (6)°.

5-Diethyl-amino-2-[(E)-(2,4-dimeth-oxy-phen-yl)imino-meth-yl]phenol.

The title Schiff base, C(19)H(24)N(2)O(3), exists in the crystal structure in the phenol-imine tautomeric form with an intra-molecular O-H⋯N hydrogen bond. The planes of the aromatic rings form a dihedral angle of 36.8 (8)°. The crystal packing is characterized by C-H⋯O hydrogen bonds and π-π stacking inter-actions [centroid-centroid distance = 3.478 (4)Å].

5-Diethyl-amino-2-{(E)-[(3-iodo-phen-yl)imino]-meth-yl}phenol.

The title Schiff base, C(17)H(19)IN(2)O, is not planar, displaying a dihedral angle of 34.9 (2)° between the two aromatic rings. The mol-ecular conformation allows the formation of a strong intra-molecular O-H⋯N hydrogen bond with graph-set motif S(6) between the hy-droxy group and the imine N atom.

(E)-N-(1-Benzothio-phen-3-yl-methyl-idene)-2,6-dimethyl-aniline.

In the title compound, C(17)H(15)NS, the benzothio-phene residue and the substituted benzene ring are oriented at a dihedral angle of 61.99 (7)°. An inter-molecular C-H⋯π inter-action contributes to the stability of the crystal structure.

(E)-3-[(2-Methyl-4-nitro-phen-yl)imino-meth-yl]-1-benzothio-phene.

In the title conpound, C(16)H(12)N(2)O(2)S, the 1-benzothio-phene residue and the substituted benzene ring are oriented at a dihedral angle of 53.36 (6)°. The mol-ecular conformation features a short C-H⋯N contact. There are no significant inter-molecular contacts.

(Z)-2-Meth-oxy-N-[(5-nitro-thio-phen-2-yl)methyl-idene]aniline.

The dihedral angle between the benzene and thio-phene rings in the title compound, C(12)H(10)N(2)O(3)S, is 27.94 (13)°. An inter-molecular C-H⋯π inter-action contributes to the stability of the crystal structure.

2-Ethyl-N-[(5-nitro-thio-phen-2-yl)methyl-idene]aniline.

In the title compound, C(13)H(12)N(2)O(2)S, the dihedral angle between the benzene and thio-phene rings is 36.72 (8)°. An inter-molecular C-H⋯π inter-action contributes to the stability of the crystal structure.

(E)-2-[3-(Trifluoro-meth-yl)phenyl-imino-meth-yl]benzene-1,4-diol.

In the title compound, C(14)H(10)F(3)NO(2), the two benzene rings are oriented at a dihedral angle of 31.94 (14)°. An intra-molecular O-H⋯N hydrogen bond helps to stabilize the mol-ecular structure. In the crystal, inter-molecular O-H⋯O hydrogen bonding links the mol-ecules, forming chains running along the crystallographic a axis. The F atoms of the trifluoro-methyl group are disordered over two positions with refined site occupancies of 0.488 (5) and 0.512 (5).

(E)-2-[(2,4-Dichloro-phen-yl)imino-meth-yl]benzene-1,4-diol monohydrate.

The title compound, C(13)H(9)Cl(2)NO(2)·H(2)O, represents a Schiff base which adopts the phenol-imine tautomeric form in the solid state. The mol-ecule is approximately planar (r.m.s. deviation 0.0818 Å), and the dihedral angle between the two aromatic rings is 7.46 (12)°. An O-H⋯N inter-action generates an S(6) ring. In the crystal, mol-ecules are linked by inter-molecular O-H⋯O hydrogen bonds involving the solvent water mol-ecule, forming chains.