Abstract: 4-Oxa-6,7-dichloroheptyltrimethoxysilane was synthesized from 4-oxa-6,7-dichlorohept-1-ene via hydrosilylation with trimethoxysilane in the presence of tetrakis (triphenylphos-phine)platinum complex as catalyst. The chlorine-containing silicon monomer was subjectedto phosphatization with potassium diphenylphosphide, immobilized on the fumed silica andreacted with potassium chloroplatinite in acetone, giving the title complex. The bidentate phosphine platinum complex was found to exhibit high catalytic activityfor the hydrosilylation of decene, dodecene, ω-chloroundecene, phenyl allyl ether,allyl ben-zene and glycidyl allyl ether with triethoxysilane. The yields of the adducts were 72 to 94%.The title complex could be recovered and reused several runs without loss of activity.

Key words: bidentate phosphine platinum complex, hydrosilylation, silica-supported catalyst