title: Comparative study of the two polymorphic forms of p-(1R,3S) 3-thioanisoyl-1,2,2-trimethylcyclopentane carboxylic acid.
abstract: The crystal structure of polymorph I of p-(1R,3S)3-thioanisoyl-1,2,2-trimethylcyclopentane carboxylic acid has been determined and is compared with that of polymorph II that was previously described. Polymorph I is very different at the level of the carboxyl group. It does not present disorder and the values found for the C-O bonds correspond exactly to single and double bond lengths. In addition, the carboxyl groups of the two molecules in the cell packing are involved in symmetric hydrogen bonds [2.662(6) A] leading to the formation of a dimer around the twofold axis following x with a shift on z. The different conformations on the carboxylic group between the two polymorphs are in good agreement with the thermodynamic study.
authors.affiliation: URA 418 ENSCM, Montpellier, France.
authors.forename: J
authors.initials: J
authors.lastname: Rambaud
authors.forename: A
authors.initials: A
authors.lastname: Bouassab
authors.forename: B
authors.initials: B
authors.lastname: Pauvert
authors.forename: P
authors.initials: P
authors.lastname: Chevallet
authors.forename: J P
authors.initials: JP
authors.lastname: Declercq
authors.forename: A
authors.initials: A
authors.lastname: Terol
mesh_terms: D001565:Benzoates / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003517:Cyclopentanes / Q000737:chemistry*; D006860:Hydrogen Bonding; D015394:Molecular Structure; D013237:Stereoisomerism; D013816:Thermodynamics
chemical_list: D001565:Benzoates; D003517:Cyclopentanes; C085799:3-thioanisoyl-1,2,2-trimethylcyclopentane-1-carboxylic acid