Synthesis and structural characterisation of [Pt2Au2(PPh3)4(CNC6H3Me2-2,6)4][PF6]2; a platinum–gold cluster with a distorted butterfly geometry

The complex [Pt2Au2(PPh3)4(CNC6H3Me2-2,6)4][PF6]2 has been synthesised from [Pt(PPh3)2(C2H4)] and [Au (CNC6H3Me2-2,6)2]+ in acetone. The cluster crystallises in the triclinic space group P with two formula units and the unit cell of dimensions a= 13.882(4), b= 15.460(2), c= 27.578(5)A, α= 77.99(5), β= 88.95(2), and γ= 67.41(5)°. The metal atoms define a distorted flattened butterfly with the gold atoms occupying the higher connectivity sites and forming a short gold–gold bond of length 2.593(2)A. The platinum–gold distances lie in the range 2.712(2)–3.028(2)A reflecting a distortion of the skeletal geometry from D2h to C2v. 31Pt-{1H} and 195Pt-{1H} n.m.r. studies suggest that in solution a symmetric D2h structure is adopted in which the gold atoms are equivalent.