Reactivity of a cluster-co-ordinated acyl. Reduction of a µ-acetyl ligand to acetaldehyde

Abstract

The action of HI on the pentanuclear carbide-cluster [Ru₅C(CO)₁₄{Au(PPh₃)}(µ-MeCO)](1) affords Au(PPh₃)I and [Ru₅C(CO)₁₄H(µ-MeCO)](2). Both (1) and (2) undergo H^– addition at low temperatures to form unstable formyl compounds which, on raising the temperature, undergo H-shift reactions to generate the hydrido-clusters [Ru₅C(CO)₁₄H{Au(PPh₃)}(µ-MeCO)]^– and [Ru₅C(CO)₁₄H₂(µ-MeCO)]^– respectively. These compounds exist in at least two isomeric forms and on heating decompose to liberate MeCHO.