Catalysis by polymer-bound Rh6 carbonyl clusters Selective hydrogenation of carbonyl compounds in the presence of CO and H2O

Functionalized polystyrenes were prepared by treatment of chloromethylated polystyrene with aminoalcohols. Using the functionalized polystyrenes and Rh6(CO)16, polymer-bound Rh cluster complexes were obtained in the presence of CO and H2O, which showed high catalytic activities for hydrogenation of aldehydes to corresponding alcohols. Activities for the hydrogenation depend on the length of spacers, and on basicity and hydrophilicity of the polymers. An active species for the hydrogenation was a hydride cluster anion of [Rh6(CO)15H]−, bound to the aminated polymer through ionic bonding with ammonium cation in the polymer. Using the polymer-bound Rh cluster catalysts, the hydrogenation occurred in a triphase system, which makes work-up procedures simple.