Bis(1,1,2,2-tetramethyldiphosphane-1,2-dithione-κ2 S,S′)gold(I) trifluoromethanesulfonate

In the title compound, [Au(C4H12P2S2)2](CF3SO3), the gold(I) atom is tightly bonded to two S atoms belonging to different ligand molecules and forms two weaker contacts to the remaining S atoms. The coordination geometry around gold is intermediate between linear-dicoordinate and tetrahedral with an S—Au—S angle of 161.49 (3)°.

In the title compound, [Au(C 4 H 12 P 2 S 2 ) 2 ](CF 3 SO 3 ), the gold(I) atom is tightly bonded to two S atoms belonging to different ligand molecules and forms two weaker contacts to the remaining S atoms. The coordination geometry around gold is intermediate between linear-dicoordinate and tetrahedral with an S-Au-S angle of 161.49 (3) .

Comment
Complexes of the group 11 metals with bidentate diphosphine disulfides ( 2 L) have so far only encompassed the lighter elements Cu and Ag (Liu et al., 2003) which readily yield [M( 2 L) 2 ] + cations. Gold complexes have not been investigated, despite the interesting results the combination of these bidentate ligands with the propensity for Au I to form linear-dicoordinate complexes could produce.
The title compound shown in Figure 1 exhibits a structure that is intermediate between classic linear-dicoordinate and tetrahedral coordination. Au I thus forms a complex of the same stoichiometry as its lighter group elements, but with a significantly different geometry. It can be envisaged as a tetrahedron formed by the sulfur donor atoms in which the gold is displaced from the centre towards an edge. The metal is coordinated by two sulfur atoms of different ligands yielding short Au-S bonds [2.3099 (7) and 2.3044 (7) Å] and is further associated with the other sulfur atoms through Au···S contacts  (Gimeno et al., 2000), which can be attributed to the absence of additional stabilizing contacts in these structures.
The [Au(C 4 H 12 P 2 S 2 ) 2 ] + cations in the crystal structure of the title compound are isolated and no intermolecular Au···Au or Au···S interactions are observed. The packing shown in Figure 2 is characterized by alternating layers of cations and anions parallel to the bc plane. The trifluoromethanesulfonate anion shows no disorder and exhibits low thermal movement.
supplementary materials sup-2 Refinement All H atoms were positioned geometrically (C-H = 0.98 Å) and constrained to ride on their parent atoms; U iso (H) values were set at 1.5 times U eq (C).
The largest residual electron density peak of 1.10 e Å -3 is located 0.83 Å from Au1. Fig. 1. Asymmetric unit of the title compound, ellipsoids are drawn at the 50% probability level. Ellipsoids are drawn at the 50% probability level, element colours correspond to those used in Figure 1.

Figures
Crystal data [Au(C 4