Vibrational frequency analysis, FT-IR and Laser-Raman spectra, DFT studies on ethyl (2E)-2-cyano-3-(4-methoxyphenyl)-acrylate.

The experimental FT-IR (4000-400 cm(-1)) and Laser-Raman spectra (4000-100 cm(-1)) of ethyl (2E)-2-cyano-3-(4-methoxyphenyl)-acrylate in solid phase have been recorded. Its theoretical vibrational frequencies, IR intensities, Raman activities and optimized geometric parameters (bond lengths and bond angles) have been calculated using density functional theory (DFT/B3LYP: Becke, 3-parameter, Lee-Yang-Parr and DFT/M06-2X: the highly parameterized empirical exchange correlation function) with 6-311++G(d, p) basis set by Gaussian 03 software, for the first time. The assignments of the vibrational frequencies have been done by potential energy distribution (PED) analysis using VEDA4 software. The optimized geometric parameters and vibrational frequencies have been seen to be in good agreement with the corresponding experimental data and results in the literature. In addition, the highest occupied molecular orbital (HOMO) energy, the lowest unoccupied molecular orbital (LUMO) energy and the other related molecular energy values of the compound have been investigated by using the same theoretical calculations.

6-(4-Fluoro-phen-yl)-3-phenyl-7H-1,2,4-tri-azolo[3,4-b][1,3,4]thia-diazine.

In the title compound, C16H11FN4S, the dihedral angles between the triazole ring and the phenyl and fluoro-benzene rings are 23.22 (17) and 18.06 (17)°, respectively. The six-membered heterocyclic ring adopts a distorted envelope conformation, with the methyl-ene C atom as the flap. In the crystal, the mol-ecules are linked by two C-H⋯N and C-H⋯F inter-actions along [010], forming C(5), C(8) and C(13) chains repectively. C-H⋯π inter-actions involving the phenyl ring and π-π inter-actions [centroid-centroid separation for triazole rings = 3.5660 (18) Å] are also observed.

2-Chloro-N-(3-meth-oxy-benzo-yl)benzene-sulfonamide.

In the title compound, C14H12ClNO4S, the dihedral angle between the chloro- and meth-oxy-substituted benzene rings is 87.40 (1)°. In the crystal, adjacent mol-ecules form inversion-related dimers through strong N-H⋯O hydrogen bonds, generating R 2 (2)(8) loops. The dimers are further connected through two C-H⋯O inter-actions that form C(11) chains and R 2 (2)(14) loops. Aromatic π-π stacking inter-actions [centroid-centroid separation = 3.8574 (1) Å] are also observed.

N-(3-Meth-oxy-benzo-yl)-2-methyl-benzene-sulfonamide.

In the title compound, C15H15NO4S, the dihedral angle between the methyl- and meth-oxy-substituted benzene rings is 88.99 (12)°. An intra-molecular C-H⋯O hydrogen bond occurs. In the crystal, adjacent mol-ecules form inversion-related dimers through strong N-H⋯O hydrogen bonds, generating R 2 (2)(8) loops. The dimers are further connected through C-H⋯O inter-actions that form C(8) chains parallel to (001). Mol-ecules are also connected through other C-H⋯O hydrogen bonds along the b axis, forming additional C(8) chains. Two aromatic π-π stacking inter-actions [centroid-centroid separations = 3.6150 (1) and 3.6837 (1) Å] generate a three-dimensional architecture.

N-(3-Meth-oxy-benzo-yl)-4-methyl-benzene-sulfonamide.

In the title compound, C15H15NO4S, the dihedral angle between the benzene rings is 88.87 (1)°. In the crystal, adjacent mol-ecules form inversion dimers through pairs of strong N-H⋯O hydrogen bonds, generating R 2 (2)(8) loops. Two C-H⋯π inter-actions and an aromatic π-π inter-action [centroid-centroid separation = 3.8191 (1) Å] are also observed.

4-(4-Methyl-phenyl-sulfon-yl)piperazin-1-ium tri-fluoro-acetate.

In the title salt, C11H17N2O2S(+)·CF3COO(-), the cation is protonated at the secondary piperazine N atom. The dihedral angle between the benzene ring and the piperazine mean plane is 85.54 (10)°. In the crystal, cations and anions are connected by two types of strong N-H⋯O hydrogen bonds into chains extending along [101]. The chains are further assembled into (10-1) layers via stacking inter-actions between benzene rings of the cations [centroid-centroid distance = 3.7319 (13) Å] and a C-H⋯O inter-action involving a piperazine C-H group and a sulfonyl O atom. Another C-H⋯O inter-action between the piperazine ring and the sulfonyl group connects the ions into a three-dimensional network.

2-[5-(2-Fluoro-phen-yl)-3-isobutyl-1H-pyrazol-1-yl]benzoic acid.

In the title compound, C(20)H(19)FN(2)O(2), the dihedral angle between the aromatic rings is 62.1 (1)°, and those between the pyrazole ring and the fluoro-benzene and benzoic acid rings are 52.1 (1) and 53.1 (1)°, respectively. In the crystal, mol-ecules are linked into [010] C(7) chains by O-H⋯N hydrogen bonds.

Ethyl (2E)-2-cyano-3-(4-meth-oxy-phen-yl)acrylate.

In the title compound, C13H13NO3, the conformation across the C=C bond is synperiplanar, the torsion angle of the segment C(ring)-C=C-C(N) being 3.2 (5)°. In the crystal, mol-ecules are linked into inversion dimers, arranged in a zigzag pattern, through two C-H⋯O inter-actions generating R 2 (2)(10) and R 2 (2)(14) motifs. These dimers are arranged in a zigzag pattern in the crystal structure. The mol-ecules are further linked along the c axis through weak C-H⋯π inter-actions, and weak π⋯π inter-actions [centroid-centroid separation = 3.9986 (17) Å] are also observed.

4-Meth-oxy-N-(pyridin-4-ylmeth-yl)-3-(tri-fluoro-meth-yl)benzamide monohydrate.

In the title compound, C15H13F3N2O2·H2O, the dihedral angle between the benzene and pyridine rings is 74.97 (1)°. The -CF3 group attached to the benzene ring is syn to the C=O bond in the adjacent side chain. In the crystal, mol-ecules are linked to one another through the water mol-ecules by strong N-H⋯O, O-H⋯O and O-H⋯N hydrogen bonds, forming a ladder-type network. The benzamide mol-ecules are also linked to one another through C-H⋯F inter-actions, forming C(6) chains parallel to the b-axis direction. Aromatic π-π stacking inter-actions [centroid-centroid separations = 3.7150 (1) and 3.7857 (1) Å] between adjacent pairs of pyridine and benzene rings are also observed, resulting in a three-dimensional architecture are also observed.

(E)-tert-Butyl 4-(N'-hy-droxy-carbam--imid-o-yl)piperazine-1-carboxyl-ate.

In the title compound, C10H20N4O3, the piperazine ring adopts a chair conformation. The mol-ecule adopts an E conformation across the C=N double bond, with the -OH group and the piperazine ring trans to one another. Further, the H atom of the hy-droxy group is directed away from the NH2 group. An intra-molecular N-H⋯O contact occurs involving the NH2 group and the oxime O atom. In the crystal, mol-ecules are linked via strong N-H⋯O and O-H⋯N hydrogen bonds with alternating R2(2)(6) and C(9) motifs into tetra-meric units forming R4(4)(28) motifs.

6-[4-Chloro-2-(trifluoro-meth-yl)phen-yl]-3-fluoro-2-methyl-pyridine.

In the title compound, C13H8ClF4N, the dihedral angle between the benzene and pyridine rings is 59.8 (3)°. In the crystal, mol-ecules are stacked in columns along the b axis through weak C-H⋯π inter-actions.

(E)-3-Chloro-N'-hy-droxy-benzene-1-carboximidamide.

The title compound, C7H7ClN2O, crystallizes with two independent mol-ecules in the asymmetric unit. The compound adopts an E configuration across the C=N double bond, as the -OH group and the benzene ring are on opposite sides of the double bond while the H atom of the hy-droxy group is directed away from the -NH2 group. In the crystal, mol-ecules are linked to one another through O-H⋯N and N-H⋯O hydrogen bonds, forming chains along [010].