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)(eta(5)-C5H3)(2); X = Et, Cl) with one or two equivalents of Mg(CH=CH2)Cl gave the new zirconacyclopentane [Zr(Cp Si2Cp){eta(2)-CH2-(CH2)(2)-CH2}] and (eta(4)-butadiene)zirconium [Zr(CpSi2C p){eta(4)-(butadiene)}] complexes, respectively. Addition of a toluene solu tion of PhC=CPh to the zirconacyclopentane compound afforded the zirconacyc lopentadiene derivative [Zr(CpSi2Cp){eta(2)-(CPh=CPh-CPh=CPh)}]. Reaction o f the chloro-ethyl zirconium complex with LiC=CPh afforded the alkynyl comp ound [Zr(CpSi2Cp)Et(C=CPh)] which reacted with CN(2,6-Me2C6H3) to give the insertion product [Zr(CpSi2Cp)(C=CPh){eta(2)-C(Et)=N(2,6-Me2C6H3)}]. Reacti ons 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-1-NMR spectroscopy. The new complexes repo rted and their intermediates have been identified by IR and H-1- and C-13-N MR spectroscopy. (C) 2000 Elsevier Science S.A. All rights reserved.