Chemistry of the metal carbonyls. Part 80. Diosmiumdiplatinum carbonyl complexes derived from tetracarbonyldihydrido-osmium. X-Ray crystal structure of [Os2Pt2(µ-H)2(CO)8(PPh3)2]

Abstract

The complexes [Pt(C₂H₄)₂(PR₃)] react at room temperature with [OsH₂(CO)₄] in light petroleum to give diosmiumdiplatinum compounds [Os₂Pt₂(µ-H)₂(CO)₈(PR₃)₂](R = Ph, cyclo-C₆H₁₁, or Me), the spectroscopic properties of which are reported. The molecular structure of the triphenylphosphine derivative was established by an X-ray diffraction study. The four metal atoms form a ‘butterfly’ cluster with the two osmium atoms at the ‘hinge’(Os–Os = 2.781₄Å) and the two platinum atoms at the ‘wingtips’(Pt ⋯ Pt = 3.206₀Å). The molecule has two-fold rotational symmetry crystallographically imposed, the two Os–Pt distances being 2.862₉ and 2.708₉Å; the longer bonds are hydrido-bridged. The platinum atoms each carry one carbonyl group and a triphenylphosphine ligand. Crystals of [Os₂Pt₂(µ-H)₂(CO)₈(PPh₃)₂] are monoclinic, a= 15.488(4), b= 12.949(3), c= 21.364(5)Å, β= 93.71 (2)°, space group C2/c. The structure was solved by heavy-atom methods and has been refined to R 0.031 (R′ 0.028) for 4 192 reflections.