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

Two different classes of silicone-modified ligands were prepared: nitrile derivatives, 4'-[3-(organosilyl)propoxy]biphenyl-4-carbonitrile R'3SiC3H6OC6H4C6H4CN (R'3Si- = a: Me3SiOSiMe2-, b: (Me(3)SiO)2SiMe-, c: Me3SiO(Me2SiO)3SiMe2-, d: Me3SiO(Me2SiO)25SiMe2-); and, pyridine derivatives, isonicotinic acid 2-methoxy-4-[3-(organosilyl)propyl]phenyl ester R'3SiC3H6Ph(O)MeOCOC5H4N . Compounds and were bound to Pd and Pt using ligand substitution reactions with organometallic precursors to give (R3SiC3H6OC6H4C6H4CN)2PdCl2, (R3SiC3H6OC6H4C6H4CN)2PtCl2 and (R3SiC3H6C6H3(OMe)OC(O)C5H4N)PtCl2(eta(2)-1-octene). The polydimethylsiloxane (PDMS)-supported Pt and Pd compounds and 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 also was effective catalyst for hydrosilylation of a diene, isoprene, with 1,1,1,3,3-pentamethyldisiloxane MM(H) to produce the 1,4-adduct Me3SiOSiMe2CH2CH=CMeCH2-H as a major product.