Synthesis of heteronuclear gold–rhodium cluster compounds and structural characterisation of [Rh(CNC8H9)3(AuPPh3)5]2+, [Rh(CNC8H9)2(AuPPh3)6(AuCl)2]+and [Rh(CO)2(AuPPh3)7]2+ - Simon Bott (J. Chem. Soc., Dalton Trans., 1991)