Reactivity of vinyl and alkynyl zirconium complexes with the di-ansa-[1,1%,2,2%-bis(dimethylsilanediyl) dicyclopentadienyl] ligand

Vinylation of the chloro–ethyl and dichloro zirconium complexes [Zr(CpSi2Cp)ClX] (CpSi2Cp=1,1%,2,2%-(SiMe2)2(h-C5H3)2; X=Et, Cl) with one or two equivalents of Mg(CH CH2)Cl gave the new zirconacyclopentane [Zr(CpSi2Cp){hCH2 (CH2)2 CH2}] and (h-butadiene)zirconium [Zr(CpSi2Cp){h-(butadiene)}] complexes, respectively. Addition of a toluene solution of PhC CPh to the zirconacyclopentane compound afforded the zirconacyclopentadiene derivative [Zr(CpSi2Cp){h(CPh CPh CPh CPh)}]. Reaction of the chloro–ethyl zirconium complex with LiC CPh afforded the alkynyl compound [Zr(CpSi2Cp)Et(C CPh)] which reacted with CN(2,6-Me2C6H3) to give the insertion product [Zr(CpSi2Cp)(C CPh){hC(Et) N(2,6-Me2C6H3)}]. Reactions of the chloro–ethyl [Zr(CpSi2Cp)EtCl] and alkynyl-ethyl [Zr(CpSi2Cp)Et(C CPh)] complexes with the Lewis acid B(C6F5)3 yielding various cationic species have been monitored by H-NMR spectroscopy. The new complexes reported and their intermediates have been identified by IR and Hand C-NMR spectroscopy. © 2000 Elsevier Science S.A. All rights reserved.