Effects of supported donor ligands on the activity and stability of tethered rhodium complex catalysts for hydroformylation

Functionalized SiO(2)-tethered rhodium complexes derived from Rh(4)(CO)(12), RhCl(PPh(3))(3) and RhHCl(PPh(3))(3) have been studied by infrared spectroscopy (IR) and solid state (31)P NMR. Rh(4)(CO)(12) and phosphinated or aminated SiO(2) are suggested to form Rh(4)(CO)(12-x)L(x) (L: supported PPh(2) or NH(2); x = 2 or 3). Rh(4)(CO)(12) reacts with thiolated SiO(2) to give [Rh(mu-L)(CO)(2)](2) (L: supported SH). The reaction of RhCl(PPh(3))(3) or RhH(CO)(PPh(3))(3) with functionalized SiO(2) is assumed to result in RhCl(PPh(3))(2)L or RhH(CO)(PPh(3))(2)L (L: supported PPh(2) or NH(2) or SH). The catalytic activity and stability of a tethered rhodium complex catalyst in cyclohexene hydroformylation shows the supported donor ligand and the catalyst precursor dependences. The aminated SiO(2)-tethered catalyst derived from Rh(4)(CO)(12) or RhCl(PPh(3))(3) displays good catalytic activity and good resistance to rhodium leaching. The thiolated SiO(2)-tethered catalyst derived from RhH(CO)(PPh(3))(3) exhibits the highest catalytic activity and good resistance to rhodium leaching. The effects of supported donor ligands on the activity and stability of tethered rhodium complex catalysts for hydroformylation are described. (C) 2003 Elsevier B.V. All rights reserved.