New High Nuclearity Platinum−Ruthenium Carbonyl Cluster Complexes Containing a Phenylacetylene Ligand: Structures and Properties

Abstract

Reaction of the mixed-metal carbonyl cluster complex Ru 5 (CO) 1 5 (C)[Pt(PBu t 3 )], 3, with PhC 2 H yielded the new compound PtRu 5 (CO) 1 3 (PBu t 3 )(μ 5 -C)(μ 3 -PhC 2 H), 4, in 41% yield. Two new bimetallic cluster complexes,Pt 2 Ru 5 (CO) 1 3 (PBu t 3 ) 2 (μ 5 -C)(μ 3 -PhC 2 H), 5, and Pt 3 Ru 5 (CO) 1 3 -(PBut 3 ) 3 (μ 5 -C)(μ 3 -PhC 2 H), 6, were subsequently obtained in 44% and 40% yield, respectively, from the reaction of 4 with an excess of Pt(PBu t 3 ) 2 . All products were characterized crystallographically by single-crystal X-ray diffraction techniques. The structure of 4 consists of a square-pyramidal cluster of five ruthenium atoms with a Pt(PBu t 3 ) group capping one of the Ru 3 triangles. A PhC 2 H ligand bridges one of the PtRu 2 triangles. Compounds 5 and 6 are similar to 4 but have in addition one and two Pt(PBu t 3 ) groups bridging one and two edges of the Ru 5 square-pyramidal portion of the cluster. Compound 6 was shown to be dynamically active on the 3 1 P NMR time scale by a process that involves an interchange of two of its inequivalent Pt(PBu t 3 ) groups.