Crystal structures of sixteen phosphane chalcogenide complexes of gold(I) chloride, bromide and iodide.

The structures of 16 phosphane chalcogenide complexes of gold(I) halides, with the general formula PAu ( = -butyl; = isopropyl; = 0 to 3; = S or Se; = Cl, Br or I), 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. However, and were badly disordered and was not obtained. The iodido derivatives are , and (numbered as for the series and ). All structures are solvent-free and all have ' = 1 except for and (' = 2). All mol-ecules show the expected linear geometry at gold and approximately tetra-hedral angles P--Au. The presence of bulky ligands forces some short intra-molecular contacts, in particular H⋯Au and H⋯. The Au- bond lengths have a slight but consistent tendency to be longer when to a softer ligand, and . The five compounds , , , and form an isotypic set, despite the different alkyl groups in . Compounds /, / and / form isotypic pairs. The crystal packing can be analysed in terms of various types of secondary inter-actions, of which the most frequent are 'weak' hydrogen bonds from methine hydrogen atoms to the halogenido ligands. For the structure type , H⋯ and H⋯ contacts combine to form a layer structure. For /, the packing is almost featureless, but can be described in terms of a double-layer structure involving borderline H⋯Cl/Br and H⋯S contacts. In and /, which lack methine groups, C-H⋯ contacts combine to form layer structures. In /, short C-H⋯ inter-actions form chains of mol-ecules that are further linked by association of short Au⋯Se contacts to form a layer structure. The packing of compound can conveniently be analysed for each independent mol-ecule separately, because they occupy different regions of the cell. Mol-ecule 1 forms chains in which the mol-ecules are linked by a C⋯Au contact. The mol-ecules 2 associate a short Se⋯Se contact and a short H⋯ contact to form a layer structure. The packing of compound can be described in terms of two short C-H⋯I contacts, which combine to form a corrugated ribbon structure. Compound is the only compound in this paper to feature Au⋯Au contacts, which lead to twofold-symmetric dimers. Apart from this, the packing is almost featureless, consisting of layers with only translation symmetry except for two very borderline Au⋯H contacts.