Rita Mathews

Crystal Structure and Conformation Study of 4-N,N-Dimethylamine Benzaldehyde Thiosemicarbazone Derivative

Thiosemicarbazones are N-N-S donor ligands having the ability to bind metal ions and inhibit ribonucleoside reductase, an enzyme important for DNA synthesis of all the mammalian cells. One of the important phenyl thiosemicarbazones, the title compound, has been synthesized and its stereo projection was analyzed by crystallographic methods. The X-ray data of DABT are C10H14N4S; M.W = 222.31, monoclinic, space group P21/n, a = 5.677(7)Å, b = 8.951(2)Å, c = 22.773(4)Å, β = 93.51(5)°; V = 1155.1(1)Å3, Z = 4, Dcal = 1.278 Mg/m3, λ (Cu K α ) = 1.54184 Å, final R1 and wR2 are 0.0563 and 0.1407, respectively. The molecular packing can be viewed as a dimer held together by two N-H · · · S type intermolecular hydrogen bonds. In addition to van der Waals forces, C-H · · · N, N-H · · · S, C-H · · · S, and N-H · · · N types of inter- and intramolecular hydrogen bonds facilitate the molecules in crystal packing.

4-({(E)-[2-(But-3-en-1-yl)-1-(prop-2-en-1-yl)-4-sulfanyl-1H-imidazol-5-yl]methyl­idene}amino)-3-phenyl-1H-1,2,4-triazole-5(4H)-thione

In the title compound, C19H20N6S2, the dihedral angle between the phenyl and triazole rings is 24.1 (2)° while the dihedral angles between the imidazole ring and the triazole and phenyl rings are 39.9 (2) and 55.3 (2)°, respectively. The crystal structure is stabilized by intermolecular N—H⋯N hydrogen bonds which form chains along [10].

Ethyl 3-methyl-2,6-diphenyl-piperidine-1-carboxyl-ate.

In the title compound, C21H25NO2, the piperidine ring adopts a twisted boat conformation characterized by puckering parameters θ = 89.5 (1) and ϕ = 257.5 (2)°. The phenyl groups are located in equatorial and axial positions on the central piperidine ring, while the methyl group is in an equatorial position. The dihedral angle between the phenyl rings is 49.8 (1)°. An intramolecular C—H⋯O interaction occurs. The crystal structure features weak intermolecular C—H⋯O interactions and a stabilizing intermolecular C—H⋯π contact involving the axial phenyl ring.

Cloning, expression, crystallization and preliminary X-ray crystallographic analysis of aspartyl aminopeptidase from the apeB gene of Pseudomonas aeruginosa. Retraction

The article by Natarajan & Mathews [(2012) (2012) Acta Cryst. F68, 207–210] is retracted.

1'-Methyl-4'-phenyl-2''-sulfanylidene-dispiro-[indoline-3,2'-pyrrolidine-3',5''-1,3-thia-zolidine]-2,4''-dione.

The title compound, C20H17N3O2S2, crystallizes with two molecules in the asymmetric unit. The pyrrolodine rings have envelope conformations in both molecules, the N atoms deviating by 0.574 (3) and 0.612 (2) Å from the mean planes through the other ring atoms. The 1′-methyl and 4′-phenyl groups on the pyrrolidine rings are substituted in equatorial positions. In the crystal, molecules are linked into a three-dimensional network by N—H⋯O, N—H⋯N and C—H⋯O and N—H⋯π hydrogen bonds.

4-Amino-3-(4-chloro­phen­yl)-1H-1,2,4-triazole-5(4H)-thione

In the title compound, C8H7ClN4S, the benzene ring is statistically disordered over two conformations rotated about the Cl—C⋯C—C axis, which subtend dihedral angles of 24.7 (3) and 9.9 (2) ° with respect to the triazole ring. An intramolecular C—H⋯N close contact occurs. In the crystal, N—H⋯N and N—H⋯S hydrogen bonds link the molecules into (001) sheets: R 2 2(8) and R 2 2(10) graph-set motifs result. Weak C—H⋯N hydrogen bonds and aromatic π–π stacking interactions [shortest centroid–centroid separation = 3.681 (7) Å] complete the structure.

(Z)-2-[(4-Methyl­phen­yl)sulfon­yl]-1,2-diphenyl­ethene­selenol

In the title compound, C21H18O2SSe, the dihedral angle between the cis phenyl rings is 64.3 (1)° and those between the toluene and the phenyl rings are 21.1 (2) and 72.0 (1)°, respectively. An intramolecular Se—H⋯O hydrogen bond occurs. In the crystal, molecules are connected by C—H⋯O hydrogen bonds and weak C—H⋯π interactions help to consolidate the crystal packing.

2,4-Diamino-5-(4-chloro­phen­yl)-6-ethyl­pyrimidin-1-ium 2-acet­amido­benzoate

The title compound, C12H14ClN4 +·C9H8NO3 −, is a salt with a 1:1 ratio of cation and anion components interacting with each other forming an R 2 2(8) ring motif. The crystal structure is stabilized by hydrogen bonds (N—H⋯O) involving two different eight-membered rings. One of them is formed between the pyrimidine ring (donor) and the carboxylate group (acceptor) from the benzoate, whereas the other ring is formed by N—H⋯O interactions, which help to form a dimer between two symmetry-related salts in the unit cell. In addition, an intramolecular C—H⋯N and intermolecular C—H⋯Cl interactions help to control the molecules in the unit-cell packing.

3-Nitroso-2,4,6,8-tetra­phenyl-3,7-diaza­bicyclo­[3.3.1]nonan-9-one

In the title compound, C31H27N3O2, the two piperidine rings fused to each other each adopt a slightly distorted chair conformation. The phenyl rings on the N-unsubstituted piperidine ring occupy an equatorial position, while those on the N-nitroso-substituted piperidine ring are in axial positions. The NO group is approximately coplanar with the piperidine ring with a maximum deviation of 0.048 (4) Å. The dihedral angles between the mean planes of the axially and equatorially oriented phenyl rings are 27.7 (1) and 31.9 (1)°, respectively. Molecular packing is stabilized by weak intermolecular C—H⋯O and C—H⋯π interactions.