Polymorphism in bipodal O,O'-dimethyl N,N'-(m-phenylenedicarbonyl)bis(thiocarbamate).
The title compound, C12H12N2O4S2, crystallizes in white and yellow polymeric forms as a result of interesting anti-anti and syn-anti conformational isomerism of the thiocarbonyl and carbonyl moieties relative to one another. This work is the first reported X-ray crystallographic structure determination of isomers of this class of bipodal ligand. The white form, anti-anti, (I), crystallizes with the benzene ring lying about a twofold rotation axis, resulting in both of the thiocarbonyl and carbonyl moieties being anti relative to each other. The yellow modification crystallizes as syn-anti, (II), with one thiocarbonyl moiety syn and the other anti relative to the respective carbonyl groups. The individual molecules of both (I) and (II) are extensively linked through intermolecular hydrogen bonds. Intermolecular hydrogen bonding in (II) includes a network of bifurcated N-H...O and N-H...S hydrogen bonds, while molecules of (I) include bifurcated C-H...O hydrogen bonds.
Department of Chemistry, University of Stellenbosch, Private Bag X1, Matieland, 7602, South Africa.
Gavin
G
Blewett
Martin W
MW
Bredenkamp
Klaus R
KR
Koch