Activation of silicon-silicon σ bonds by transition-metal complexes:: synthesis and catalysis of new organosilyl transition-metal complexes

Stoichiometric and catalytic reactions of organosilicon compounds having Si-Si bonds with palladium and platinum complexes are described. Bis(organosilyl)-palladium(n) and -platinum(rr) complexes were synthesized by reactions of disitanes with palladium(o)- and platinum(o)-isocyanide complexes. Reactions of bis(disilanes) such as bis(disilanyl)dithianes with the palladium(o) and platinum(o) complexes afforded cyclic bis(organosilyl)palladium(lr) complexes and a tetrakis(organosilyl)platinum(IV) complex, respectively, via simultaneous activation of the two Si-Si bonds of the bis(disilanes), On the basis of the stoichiometric investigations, catalytic intramolecular bis-silylation of carbon-carbon multiple bonds and ring-enlargement oligomerization of cyclic disilanes were achieved by use of palladium(o)isocyanide catalysts, demonstrating synthetic utility of the Si-Si bond activation. On the other hand, activation of the Si-Si bonds by palladium(n) complexes, which is crucially involved in ring-opening polymerization of cyclic disilanes, enabled synthesis of cyclopentadienyltris(organosilyl)palladium(Iv) complexes by reaction of a spiro-trisilane with cyclopentadienyl(allyl)palladium(n) complexes.