NONBRIDGED HALF-TITANOCENES CONTAINING ANIONIC ANCILLARY DONOR LIGANDS: PROMISING NEW CATALYSTS FOR PRECISE SYNTHESIS OF CYCLIC OLEFIN COPOLYMERS (COCs)

Precise,efficient copolymerizations of ethylene with cyclic olefins[norbomene(NBE),cyclopentene (CPE) using nonbridged half-titanocenes of type,Cp'TiCI2(L)(Cp'=cyclopentadienyl group,L=aryloxo,ketimide)-MAO catalyst systems have been summarized.CpTiCI2(N=C'Bu2) exhibited both remarkable camlytic activity and efficient NBE incorporation for ethylene/NBE copolymerization:the NBE incorporation by Cp'TiCI2(X)(X=N=C'Bu2,O-2,6-'Pr2C6H3;Cp'=Cp,C5Me5,indenyl) was related to the calculated coordination energy after ethylene insertion.('BuC5H4)TiCI2(N=C'Bu) exhibited significant catalytic activities with efficient CPE incorporations in ethylene/CPE copolymerization in the presence of MAO.The polymerization proceeded with exclusive 1,2-CPE incorporation.affording high molecular weight (altemating)copolymers with uniform distributions.Therefore,the cyclopentadienyl fragment(Cp')plays an essential role in terms of both the activity and the efficient cyclic olefin incorporation.