Fixation and spontaneous dehydrogenation of methanol on a triruthenium–iridium framework: synthesis and structure of the cluster anion [HRu₃Ir(CO)₁₂(OMe)]^–

The anionic mixed-metal cluster [Ru₃Ir(CO)₁₃]^–<b>1</b>, found to be catalytically active in the carbonylation of methanol, reacts with methanol at 70 °C to give, with O–H activation of the substrate, the cluster anion [HRu₃Ir(CO)₁₂(OMe)]^–<b>2</b>, which upon prolonged reaction loses formaldehyde to give the cluster anion [H₂Ru₃Ir(CO)₁₂]^–<b>3</b>; both anions <b>2</b> and <b>3</b> crystallise together as the double-salt [N(PPh₃)₂]₂[HRu₃Ir(CO)₁₂(OMe)][H₂Ru₃Ir(CO)₁₂] the single-crystal X-ray structure analysis of which reveals a butterfly Ru₃Ir skeleton for <b>2</b> and a tetrahedral Ru₃Ir skeleton for <b>3</b>.