Siloxane-supported organometallic compounds and their catalytic activities for the hydrosilylation of vinylsilanes and dienes

摘要

Two different classes of silicone-modified ligands were prepared: nitrile derivatives, 4'-[3-(organosilyl) propoxy]biphenyl- 4-carbonitrile R'3SiC3H6OC6H4C6H4CN 2 (R'Si-3 - = a: Me3SiOSiMe2 -, b: (Me3SiO)(2)SiMe-, c: Me3SiO(Me2SiO)(3)SiMe2-, d: Me3SiO(Me2SiO)(25)SiMe2-); and, pyridine derivatives, isonicotinic acid 2-methoxy-4[ 3-(organosilyl) propyl] phenyl ester R'3SiC3H6Ph(OMe) OC(O) C5H4N 6. Compounds 2 and 6 were bound to Pd and Pt using ligand substitution reactions with organometallic precursors to give (R3SiC3H6OC6H4C6H4CN)(2)PdCl2 3, (R3SiC3H6OC6H4C6H4CN)(2)PtCl2 4 and (R3SiC3H6C6H3(OMe) OC(O) C5H4N) PtCl2(eta(2)-1-octene) 8. The polydimethylsiloxane (PDMS)-supported Pt and Pd compounds 3d and 4d had excellent solubility in both organic solvents and polysiloxanes. All the Pt compounds exhibited good catalytic activity for hydrosilylation of vinylsilanes. The PDMS-supported Pd compound 3d alsowas effective catalyst for hydrosilylation of a diene, isoprene, with 1,1,1,3,3-pentamethyldisiloxane MMH to produce the 1,4-adduct Me3SiOSiMe2CH2CH=CMeCH2-H as a major product.