B. K. Revathi

Crystal structure of 4-chloro-N-[2-(piperidin-1-yl)eth-yl]benzamide monohydrate.

In the title compound, C14H19ClN2O2·H2O, the piperdine ring adopts a chair conformation. The dihedral angle between the mean plane of the piperidine ring and that of the phenyl ring is 41.64 (1)°. In the crystal, molecules are linked by O—H⋯N, N—H⋯O and C—H⋯O hydrogen bonds involving the water molecule, forming double-stranded chains propagating along [010].

2-Chloro-1-(3,3-dimethyl-2,6-di­phenyl­piperidin-1-yl)ethanone

In the title compound, C21H24ClNO, the piperidine ring adopts a chair conformation. The two phenyl rings are inclined to one another by 20.7 (1)°, and are inclined to the mean plane of the four planar atoms of the piperidine ring by 87.64 (10) and 70.8 (1)°. The molecular structure features short intramolecular C—H⋯Cl and C—H⋯O contacts. In the crystal, there are no significant intermolecular interactions present.

Crystal structure of (E)-1-(1-hy-droxy-naphthalen-2-yl)-3-(2,3,4-tri-meth-oxy-phen-yl)prop-2-en-1-one.

The title compound, C22H20O5, is composed of a hydroxynaphthyl ring and a trimethoxyphenyl ring [the planes of which are inclined to one another by 21.61 (10)°] bridged by an unsaturated prop-2-en-1-one group. The mean plane of the prop-2-en-1-one group [–C(=O)—C=C–] is inclined to that of the naphthyl system and benzene rings by 3.77 (14) and 18.01 (16)°, respectively. There is an intramolecular O—H⋯O hydrogen bond present forming an S(6) ring motif. In the crystal, inversion-related molecules are linked by a slipped-parallel π–π interaction [intercentroid distance = 3.8942 (13) Å, interplanar distance = 3.478 (9) Å and slippage = 1.751 Å], and stack along the [101] direction. There are no other significant intermolecular interactions present.

Crystal structure of (E)-3-(3,4-di-meth-oxy-phen-yl)-1-(1-hy-droxy-naphthalen-2-yl)prop-2-en-1-one.

The molecular structure of the title compound, C21H18O4, consists of a 3,4-dimethoxyphenyl ring and a naphthalene ring system linked via a prop-2-en-1-one spacer. The molecule is almost planar, with a dihedral angle between the benzene ring and the naphthalene ring system of 2.68 (12)°. There is an intramolecular O—H⋯O hydrogen bond involving the adjacent hydroxy and carbonyl groups. The molecule has an E conformation about the C=C bond and the carbonyl group is syn with respect to the C=C bond. In the crystal, molecules are linked by bifurcated C—H⋯(O,O) hydrogen bonds, enclosing an R 2 1(6) ring motif, and by a further C—H⋯O hydrogen bond, forming undulating sheets extending in b- and c-axis directions. There are π–π interactions between the sheets, involving inversion-related naphthalene and benzene rings [intercentroid distance = 3.7452 (17) Å], forming a three-dimensional structure.

Crystal structure of bis­(prop-2-yn-1-yl) 5-nitro­isophthalate

The whole molecule of the title compound, C14H9NO6, is generated by twofold rotation symmetry; the twofold axis bisects the nitro group and the benzene ring. The nitro group is inclined to the benzene ring by 14.42 (9)°. The prop-2-yn-1-yl groups are inclined to the benzene ring by 13 (2)° and to each other by 24 (3)°; one directed above the plane of the benzene ring and the other below. In the crystal, molecules are linked via pairs of C—H⋯O hydrogen bonds, forming inversion dimers with an R 2 2(18) ring motif. The dimers are linked by further C—H⋯O hydrogen bonds, forming sheets lying parallel to (100).

Crystal structure of [4-(chloro-meth-yl)phen-yl](4-hy-droxy-piperidin-1-yl)methanone.

The title compound, C13H16ClNO2, crystallized with two independent molecules in the asymmetric unit (A and B). The piperidinol ring in molecule B is disordered over two positions with a site occupancy ratio of 0.667 (5):0.333 (5). In both molecules these rings have a chair conformation, including the minor component in molecule B. Their mean planes are inclined to the benzene ring by 45.57 (13)° in molecule A, and by 50.5 (4)° for the major component of the piperidine ring in molecule B. In the crystal, the individual molecules are linked by O—H⋯O hydrogen bonds, forming chains of A and B molecules along the [100] direction. The chains are interlinked by C—H⋯O hydrogen bonds, forming ribbons.

Crystal structure of (4-hy-droxy-piperidin-1-yl)[4-(tri-fluoro-meth-yl)phen-yl]methanone.

The title compound, C13H14NO2F3, crystallises with two molecules, A and B, in the asymmetric unit, with similar conformations. The dihedral angles between the piperidine and phenyl rings are 83.76 (2) and 75.23 (2)° in molecules A and B, respectively. The bond-angle sums around the N atoms [359.1 and 359.7° for molecules A and B, respectively] indicate sp 2 hybridization for these atoms. In the crystal, O—H⋯O hydrogen bonds link the molecules into separate [100] chains of A and B molecules. The chains are cross-linked by C—H⋯O interactions, generating alternating (001) sheets of A and B molecules.

Crystal structure of 2,2,4-trimethyl-2,3,4,5-tetra-hydro-1H-benzo[b][1,4]diazepine hemihydrate.

The title compound, C12H18N2·0.5H2O, crystallizes with two independent organic molecules (A and B) in the asymmetric unit, together with a water molecule of crystallization. The diazepine rings in each molecule have a chair conformation. The dihedral angle between benzene ring and the mean plane of the diazepine ring is 21.15 (12)° in molecule A and 17.42 (11)° in molecule B. In the crystal, molecules are linked by N—H⋯O and O—H⋯N hydrogen bonds, forming zigzag chains propagating along [001].

Crystal structure of 3-(4-meth-oxy-phen-yl)-2,3-di-hydro-1H-naphtho-[2,1-b]pyran-1-one.

In the title compound, C20H16O3, the hydropyran ring adopts a distorted half-chair conformation with the methine C atom and the ring O atom displaced by −0.554 (2) and 0.158 (1) Å, respectively, from the plane of the other four atoms (r.m.s. deviation = 0.020 Å). Its mean plane (all atoms) is inclined to the naphthalene ring system at a dihedral angle of 11.67 (1)°. The dihedral angle between the napthalene ring system and the phenyl ring is 71.84 (1)°. In the crystal, no diectional interactions beyond van der Waals contacts could be identified.

Crystal structure of (4-hy-droxy-piperidin-1-yl)(4-methyl-phen-yl)methanone.

In the title compound, C13H17NO2, the dihedral angle between the planes of the piperidine and benzene rings is 51.7 (2)°. The bond-angle sum around the N atom [359.8 (3)°] indicates sp 2 hybridization of the atom. In the crystal, O—H⋯O hydrogen bonds link the molecules, forming chains along [001].