Chemistry of di- and tri-metal complexes with bridging carbene or carbyne ligands. Part 45. Synthesis of the pentanuclear metal complexes [M′M2Re2(µ-CC6H4Me-4)2(CO)18](M′= Ni or Pt, M = Cr or W) and related compounds; X-ray crystal structure of [ReWPt(µ-CC6H4Me-4)(CO)9(PMe3)2]

Abstract

The pentanuclear metal compounds [M′M₂Re₂(µ-CC₆H₄Me-4)₂(CO)₁₈](M′= Pt or Ni, M = Cr or W) have been prepared by treating the complexes [ReM(CC₆H₄Me-4)(CO)₉] with [Pt(C₂H₄)₃] Or [Ni(cod)₂](cod = cyclo-octa-1,5-diene), respectively. Similarly, the species [ReM(CC₆H₄Me-4)(CO)₉] react with the platinum compounds [Pt(C₂H₄)₂{P(cyclo-C₆H₁₁)₃}] and [Pt(C₂H₄)(PMe₃)₂] to afford the trimetal complexes [ReWPt(µ-CC₆H₄{Me-4)(CO)₁₀{P(cyclo-C₆H₁₁)₃}] and [ReMPt(µ-CC₆H₄Me-4)(CO)₉(PMe₃)₂](M = Cr or W), respectively. An X-ray diffraction study on the compound [ReWPt(µ-CC₆H₄Me-4)(CO)₉(PMe₃)₂] shows that the molecule has a bent Re–W–Pt [151.3(1)°] spine, with metal–metal distances Re–W 3.082(1) and W–Pt 2.771(1)Å. The W–Pt bond is bridged by the CC₆H₄Me-4 group [µ-C–W 2.01 3(24), µ-C–Pt 1.962(23)Å]. The rhenium atom is ligated by five CO groups orthogonally disposed, so that the metal is in an octahedral environment, the sixth site being occupied by the Re–W bond. The platinum atom carries the two PMe₃ ligands [P–Pt–P 98.6(2)°] and the tungsten atom four CO groups. The latter are radially disposed so that the tungsten is in a distorted octahedral environment with respect to these CO ligands; the Re(CO)₅ group, and the mid-point of the µ-C–Pt bond [Re–W–µ-C 163.1(6), Re–W–Pt 151.3(1)°]. The radial CO groups on rhenium and tungsten are staggered with respect to each other about the Re–W bond.