EXAFS characterization and selective olefin hydroformylation on Rh4, Rh2Co2 and RhCo3 carbonyl clusters attached to tris-hydroxymethylphosphine-grafted silica

Rh_4-xCo_x(CO)₁₂ (x = 0, 2, 3) are attached by carbonyl substitution to THP (tris-hydroxymethylphospine)-grafted silica keeping their cluster frameworks. They have been characterized by Rh K-edge EXAFS (extended X-ray absorption fine structure) and Fourier transform IR spectroscopy. They exhibited high catalytic activity with > 98% selectivity in gas phase hydroformylation of ethene and propene to give aldehydes under mild conditions (40 kPa and 300–373 K).On leave from Research Center, Arakawa Chemical Industries, LTD, Tsurumi, Osaka 538, Japan.On leave from Department of Chemistry, National University of Literal, Santiago del Estero, 2829-3000, Santa Fe, Argentina.