The heteronuclear cluster chemistry of the Group 1B metals. Part 5. X-Ray crystal structure and dynamic behaviour of the heptanuclear mixed-metal cluster [Au3Ru4(µ-H)(CO)12(µ-Ph2PCH2PPh2)(PPh3)]

Abstract

A single-crystal X-ray diffraction study of the mixed-metal gold cluster [Au₃Ru₄(µ-H)(CO)₁₂(µ-Ph₂PCH₂PPh₂)(PPh₃)](1) reveals a different core geometry to the bicapped trigonal-bipyramidal structure adopted by the closely related species [Au₃Ru₄(µ₃-H)(CO)₁₂(PPh₃)₃](2). The metal skeleton of (1) may be described as a distorted Au₂Ru₃ square pyramid with two adjacent triangular faces capped by the metal atoms of a Ru(CO)₃ and a Au(PPh₃) unit. The Ph₂PCH₂PPh₂ group bridges the Au–Au edge of the square base of the pyramid, the hydrido ligand bridges a Ru–Ru edge of the capping Ru(CO)₃ unit, and each ruthenium atom is bonded to three terminal carbonyl groups. Knowledge of the structure of (1) allows further insight into the nature of the dynamic behaviour that (1) and (2) exhibit in solution at ambient temperature.