Thermolysis of Ru3(CO)10(μ-dppm) and Ru3(CO)9(PRPh2)(μ-dppm) (R = Ph, H) in presence of O2: Synthesis and structure of triruthenium clusters containing a capping-oxo ligand

Abstract

Thermolysis of Ru3(CO)10(μ-dppm) [dppm=bis(diphenylphosphino)methane] in boiling xylene in presence of molecular oxygen (O2) affords the trinuclear oxo-capped cluster Ru3(CO)7(μ3-CO)(μ3-O)(μ-dppm) (1). A similar reaction between Ru3(CO)9(PPh3)(μ-dppm) and O2 in refluxing benzene also furnishes the oxo-capped Ru3(CO)6(PPh3)(μ3-CO)(μ3-O)(μ-dppm) (2). Crystal structures of 1 and 2 reveal that both contain a capping oxygen at one face and a triply-bridging carbonyl on the opposite face of the triruthenium plane. In contrast, Ru3(CO)9(PHPh2)(μ-dppm) does not react with O2 under similar conditions, but undergoes thermal transformations to give Ru3(CO)7(μ-H)(μ-PPh2){μ3-PhPCH2P(C6H4)Ph} (3) and Ru3(CO)6(μ-CO)(μ-PPh2)2(μ3-CH2PPh)] (4) via C–P, P–H and C–H bond activation. All the new clusters have been characterized by a combination of spectroscopic data and single crystal X-ray diffraction analysis.