Polymorphism in (Tricyclohexylphosphine)gold(I) 2-MercaptobenzoateA Tale of Two Structural Motifs

(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).