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(η5-C5H3)2; X=Et, Cl) with one or two equivalents of Mg(CH=CH2)Cl gave the new zirconacyclopentane [Zr(CpSi2Cp){η2-CH2-(CH2)2-CH2}] and (η4-butadiene)zirconium [Zr(CpSi2Cp){η4-(butadiene)}] complexes, respectively. Addition of a toluene solution of PhC=CPh to the zirconacyclopentane compound afforded the zirconacyclopentadiene derivative [Zr(CpSi2Cp){η2-(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){η2-C(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 1H-NMR spectroscopy. The new complexes reported and their intermediates have been identified by IR and 1H- and 13C-NMR spectroscopy