Heteronuclear Hexaplatinum Cluster Complexes: Structure as a Function of Electron Count

The 84-electron hexaplatinum cluster complex [Pt6(μ-CO)6(μ-dppm)3], 1, dppm = Ph2PCH2PPh2, reacts in a 1:2
molar ratio with either 0-electron metalloligands LM+ (L = Ph3P, M = Cu, Ag, Au; L = iPr3P, M = Au) or InX3
(X = Cl, Br) or 2-electron metalloligands Tl+ and Hg to give the corresponding 84-electron clusters [Pt6(μ3-ML)2(μ-CO)6(μ-dppm)3]2+ or [Pt6(μ3-InX3)2(μ-CO)6(μ-dppm)3] or 88-electron clusters [Pt6(μ3-Tl)2(μ-CO)6(μ-dppm)3]2+ and [Pt6(μ3-Hg)2(μ-CO)6(μ-dppm)3], respectively. The mercury cluster is oxidized by CH2I2 to give
the known 86-electron cluster [Pt6(μ3-HgI)2(μ-CO)6(μ-dppm)3]. Reaction of 1 with [Ir(CO)4]- occurs in a 1:1
ratio only to give the 98-electron anionic cluster [Pt6{μ3-Ir(CO)2}(μ-CO)6(μ-dppm)3]-, which reacts with [Ph3PAu]+ to give [Pt6{μ3-Ir(CO)2}(μ3-AuPPh3)(μ-CO)6(μ-dppm)3]. The new cluster complexes are characterized
by NMR and IR spectroscopies, and [Pt6(μ3-AuPiPr3)2(μ-CO)6(μ-dppm)3]2+ is also characterizedby an X-ray
structure determination.