Dinuclear ruthenium and iron complexes containing palladium and platinum with tri-tert-butylphosphine ligands:: Synthesis, structures, and bonding

The reaction of Pd(PBu3t)(2) with Ru(CO)(5) yielded the dipalladium-di ruthenium cluster complex Ru-2(CO)(9)[Pd(PBu3t)](2), 10. The reaction of Pt(PBu3t)(2) with Ru(CO)(5) at room temperature afforded the diplatinum-diruthenium cluster complex Ru-2(CO)(9)[Pt(PBu3t)](2), 12, and the monoplatinum-diruthenium cluster PtRu2(CO)(9)(PBu3t), 11. All three complexes contain a diruthenium group with bridging Pd(PBu3t) or Pt(PBu3t) groups. Compound 11 can be converted to 12 by reaction with an additional quantity of Pt(PBu3t)(2). The reaction of 12 with hydrogen at 68 degreesC yielded the dihydrido complex Pt2Ru2(CO)(8)(PBu3t)(2)(mu-H)(2), 13. This complex contains a Ru2Pt2 cluster with hydride ligands bridging two of the Ru-Pt bonds. The reaction of Fe-2(CO)(9) With Pt(PBu3t)(2) yielded the platinum-diiron cluster complex PtFe2(CO)(9)(PBu3t), 14, which is analogous to 11. All new complexes were characterized crystallographically, Molecular orbital calculations of 10 reveal an unusual delocalized metal-metal bonding system involving the Pd(PBu3t) groups and the Ru-2(CO)(9) group.