K. Subramanian

X-ray structure of 3-phenylthio-2-[1′-phenylsulfonyl-2′(3-pyridyl)vinyl]indole and its interaction with calf thymus DNA by spectroscopic methods

Abstract The main skeleton of the 3-phenylthio-2-[1′-phenylsulfonyl-2′(3-pyridyl)vinyl]indole molecule consists of an indole ring system with phenylthio, phenylsulfonyl and pyridine rings as exocyclic substituents. The cell parameters are a = 13.862(1), b = 10.948(1), c = 15.303(1) A and β = 98.47(2)°. The planar indole ring system is slightly folded along C(8)–C(9). The phenylthio is perpendicular to indole ring system, whereas phenylsulfonyl and pyridine are in inclined positions. The molecules in the unit cell are stabilized by van der Waals force of interaction. The study of the interaction of this molecule with DNA shows the evidence for the formation of a complex with DNA.

N-(p-methoxyphenyl)-N-prop-2-ynyl-urea: a crystal structure with the rare Z'=5, and statistical data on Z' values

Abstract The crystal structure of N-(p-methoxyphenyl)-N-prop-2-ynyl-urea contains five symmetry-independent molecules (Z′=5), which is a high and rarely occurring value. The five molecules have similar but not identical conformations, and form similar but not identical intermolecular interactions. The terminal alkyne groups of the five molecules are oriented differently, and form different hydrogen bond interactions (C–H⋯O and C–H⋯π). This is an example of how simple molecules can form a highly complicated solid state structure.

CRYSTAL STRUCTURE OF N-CYANO-N-PROP-2-YNYL-ANILINE AND STRUCTURAL DATA ON CC-H...N HYDROGEN BONDS

Abstract In the crystal structure of N -cyano- N -prop-2-ynyl-aniline, the propynyl group does not form the expected dominant intermolecular interaction, but only a very long and distorted contact to the cyano acceptor. Despite the long H⋯N separation of 2.75xa0A, the infrared absorption spectrum indicates weakly hydrogen bonding nature of this contact. A short database analysis on hydrogen bonds from terminal alkynes to N acceptors is also performed, showing that the hydrogen bond in the title compound is the longest of this kind observed as yet.

NH···CCH hydrogen bonds as part of cooperative networks: crystal structure of N-(p-methylphenyl)-N-prop-2-ynylurea

Abstract In the crystal structure of N-(4-methylphenyl)-N-prop-2-ynylurea, urea dimers are formed which are linked by cooperative Nue5f8H···Cue5fcCue5f8H···O hydrogen bonds, leading to an infinite two-dimensional hydrogen bond network.

Piscidinol-C, a triterpenoid from Walsura piscidia leaves

The X-ray crystal structure of the triterpenoid piscidinol-C from the leaves of Walsura piscidia is determined. The compound, which is an apotirucallane derivative, crystallizes in the orthorhombic space group C2221 with a = 18.985(4), b = 13.092(5), c = 24.690(7) Å, and Dcalc = 1.209 g cm−1 for Z = 8.

Crystal and molecular structure of 7-hydroxyflavone monohydrate, C14H10O3·H2O

The X-ray crystal structure of 7-hydroxyflavone monohydrate, C14H10O3 · H2O, is determined. The compound crystallizes in the monoclinic space group, P21/n with a = 3.801(3), b = 19.665(4), c = 16. 039(6), β = 93.69(3)°, and μ = 0.68 mm−1 for Z = 4. The phenyl ring of the flavone moiety is rotated 18.6(1)° out of the penzopyran plane, which is a typical value for flavones. In the crystal lattice, there are wide channels which are lined mainly by C–H groups. The water molecules enclosed in these channels are severely disordered.

X-ray structure of 5-[2-chlorophenyl]-10-[4-methylphenyl] 1,2,5,8,9,10 hexahydro 4,6[3H,6H] acridinedione and its interaction with calf thymus DNA by spectroscopic methods

Abstract The molecule [C26H24O2 NCl] mainly consists of a partially hydrogenated acridine ring system, with one phenyl and chlorophenyl substituent at the central pyridine ring. The cell parameters are; a = 10.715(1), b = 11.183(1), c = 9.267(2) A . α = 90.31(1), β = 105.58(1) and γ = 88.56(2)°. The central part of acridine ring adopts a boat conformation. Of the two outer 6-membered rings of the acridine moiety, one adopts a conformation intermediate between a sofa and a half-chair (ring I), while the other adopts a twist (ring III) conformation. The methyl substituted phenyl ring is equatorial and the chlorophenyl ring is axial with respect to the central pyridine ring. The acridine ring system is considerably folded along the bonds at the ring junctions. The chlorophenyl and phenyl rings are nearly parallel to each other. Packing of the molecules mainly involves van der Waals interactions. A preliminary DNA interaction study of this molecule has been carried out using spectroscopic methods. It shows evidence for the formation of a complex between dye and DNA. The results are interpreted in terms of its crystal structure.

Anticooperative C—C—H···O···H—O hydrogen bonding in 5β-Hydroxy-5α-ethynyl-10β-methyl-Δ1(9)-octalin-2-one

In the x-ray crystal structure of the alkynol 5β-hydroxy-5α-ethynyl-10β-methyl-Δ1(9)-octalin-2-one [C13H16O2, Pbca, a = 10.244(7), b = 12.734(2), c = 17.125(2) Å, Z = 8], the hydroxyl and ethynyl groups are involved in a hydrogen bond arrangement C—C—H···O···H—O, which is supposed to be anticooperative, i.e., weaker than the sum of two isolated hydrogen bonds.

Cooperative C≡C-H⋯O-H⋯O hydrogen bonding in a crystalline alkynol

In the X-ray crystal structure of the alkynol 5β-hydroxy-5α-(prop-2-ynyl)-10β-methyl-Δ1(9)-octalin-2-one [C14H18O2, Pca21, a = 13.559(1), b = 7.960(2), c = 21.748(3) Å], the hydroxyl and propynyl groups form a hydrogen bond chain C---C-H⋯O-H⋯O which is supposed to be a cooperative arrangement. Quantum chemical calculations estimate cooperativity enhancement within the array to be 0.4 kcal/mol, which is only a small (but recognizable) effect.

Racemic γ-2-cis-6-diphenyl-trans-3-ethylpiperidin-4-one oxime, a crystal structure with Z′ = 8

The crystal structure of the title compound contains eight molecules per asymmetric crystal unit, each four of the two enantiomers (Pa, a = 19.7547(3) Å, b = 17.2606(2) Å, c = 20.8149(4) Å, β = 114.2656(16)°, V = 6470.4(2) Å3, Z = 16). The independent molecules have significantly different conformations, and local pseudosymmetries are obeyed only very roughly. The oxime groups form the typical hydrogen bonded cyclic dimers, whereas the amine donors are not satisfied by any kind of hydrogen bonds.