Crystal structures of ten phosphane chalcogenide complexes of gold(III) chloride and bromide.

The structures of ten phosphane chalcogenide complexes of gold(III) halides, with general formula PAu ( = -butyl; = -propyl; = 0 to 3; = S or Se; = Cl or Br) are presented. The eight possible chlorido derivatives are: , = 3, = S; , = 2, = S; , = 1, = S; , = 0, = S; , = 3, = Se; , = 2, = Se; , = 1, = Se; and , = 0, = Se, and the corresponding bromido derivatives are - in the same order. Structures were obtained for , (and a second polymorph ), (and its deutero-chloro-form monosolvate ), (as its di-chloro-methane monosolvate), , (as its deutero-chloro-form monosolvate , in which the solvent mol-ecule is disordered over two positions), , , and . The structures of , , and form an isotypic set, and those of compounds and form an isotypic pair. All structures have ' = 1. The gold(III) centres show square-planar coordination geometry and the chalcogenide atoms show approximately tetra-hedral angles (except for the very wide angle in , probably associated with the bulky -butyl groups). The bond lengths at the gold atoms are lengthened with respect to the known gold(I) derivatives, and demonstrate a considerable influence of S and Se donor atoms on a Au-Cl bond. Each compound with an isopropyl group shows a short intra-molecular contact of the type C-H⋯; these may be regarded as intra-molecular 'weak' hydrogen bonds, and they determine the orientation of the Au groups. The mol-ecular packing is analysed in terms of various short contacts such as weak hydrogen bonds C-H⋯ and contacts between the heavier atoms, such as ⋯ (, , , and ), S⋯S (, and ) and S⋯Cl (). The packing of the polymorphs and is thus quite different. The solvent mol-ecules take part in C-H⋯Cl hydrogen bonds; for , a disordered solvent region at ≃ 0 is observed. Structure involves unusual inversion-symmetric dimers with Se⋯Au and Se⋯Br contacts, further connected by Br⋯Br contacts.