Superloading of tin ligands into rhodium and iridium carbonyl cluster complexes

The reactions of Rh-4(CO)(12) and Ir-4(CO)(12) with Ph3SnH have yielded the new Rh-Sn and Ir-Sn cluster complexes M-3(CO)(6)(mu-SnPh2)(3)(SnPh3)(3), 1 (M = Rh) and 2 (M = Ir). Both compounds contain triangular M3 clusters with three bridging SnPh2 and three terminal SnPh3 ligands. The M-M bonds are unusually long. Molecular orbital calculations indicate that this is due to the importance of M-Sn bonding and weak direct M-M interactions. Reaction of 1 with Ph3SnH at reflux in 1,2-dichlorobenzene solvent yielded the complex Rh-3(CO)(3)(SnPh3)(3)(mu-SnPh2)(3)(mu(3)-SnPh)(2), 3, which contains eight tin ligands: three terminal SnPh3, three edge-bridging SnPh2, and two triply bridging SnPh ligands.