Behaviour of [Ru(CO)2(MeCO2)2(PBun3)2] in the presence of carbon monoxide and/or hydrogen: crystal structure of [Ru6(µ-H)6(CO)10(µ-PHBun)(µ-PBun2)2-(PBun3)2(µ6-P)]

Abstract

The behaviour of [Ru(CO)₂(MeCO₂)₂(PBuⁿ₃)₂] in the presence of N₂, CO, H₂, or a mixture of the last two gases has been investigated. When heated, especially in the presence of CO and/or H₂, acetato and phosphido ligands are lost. At higher temperature, under hydrogen, but in the absence of alternative free ligands, a metal cluster hydride derivative, [Ru₆(µ-H)₆(CO)₁₀(µ-PHBuⁿ)(µ-PBuⁿ₂)₂(PBuⁿ₃)₂(µ₆-P)], is formed. An X-ray crystal structure analysis has shown that the shape of this metal cluster is ‘butterfly’ like with two pairs of triangular wings, encapsulating a bare phosphide phosphorus and carrying three bridging phosphides and two terminal phosphine ligands. The sides of the wings not bridged by the phosphido phosphorus are bridged by hydride hydrogens in such a way that the moiety formed by the metal, phosphorus, and hydride hydrogen atoms shows a local non-crystallographic C₂ symmetry. Two carbonyl ligands complete the metal co-ordination about each ruthenium atom except those of the base hinge that are bound to only one carbonyl each.