SYNTHESIS, STRUCTURE, AND OXIDATION-INDUCED DIMERIZATION OF A CHELATING BIS(PHOSPHITE) RUTHENIUM CARBONYL

The novel bis(phosphite) compound Ru(bbmb)(CO)3 (1) (bbmb: hite]-3,3-d i-t-butyl-5,5'-dimethoxy-1,1'-biphenyl} was synthesized by the high pr essure reaction of Ru3(CO)12 with bbmb, and fully characterized by com bustion, spectroscopic, spectrometric and structural analysis. The str ucture of 1, as determined by X-ray diffraction, is a nearly perfect t rigonal bipyramid with the bbmb ligand coiled about Ru in an overall C 2 fashion. Reaction of 1 with [Cp2Fe][PF6] gave [Ru2(mu-bbmb)2(CO)6][P F6]2 (2) whose formulation is based on combustion and spectroscopic an alysis. It is shown that 2 contains a pair of bridging bbmb ligands. T he significance of 1 in relation to structure-activity in the regiosel ectivity of the hydroformylation reaction is discussed. Formation of 2 from 1 is addressed in the context of the reactivity of pentacoordina te radical cation complexes.