Web Release Date: December 23,
Polymorphism in (Tricyclohexylphosphine)gold(I) 2-Mercaptobenzoate-A Tale of Two Structural Motifs
and
Department of Chemistry, The University of Adelaide, Adelaide, Australia 5005, and Molecular Structure Corporation, 9009 New Trails Drive, The Woodlands, Texas 77381-5290
Received September 18, 2000
Abstract:
(Tricyclohexylphosphine)gold(I) 2-mercaptobenzoate is found in four distinct crystal forms. All forms show a linear P-Au-S geometry. In three of the polymorphs the molecule may be described as spherical, as a result of an intramolecular O-H···S bond formed between the carboxylic acid group and the coordinated sulfur atom: i.e., a "ball" motif. These are in contrast to a "rod" motif (previously reported) that features association between centrosymmetric molecules via the familiar carboxylic acid dimer. Both motifs may be obtained under the same crystallizing conditions, a result which indicates that there is little energy difference between the different crystal forms. The process of crystallization may be described as a competition between the efficient crystal packing (ball motif) and the formation of carboxylic acid dimers (rod motif).
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