No abstract

No abstract

No abstract

A series of phenoxy-substituted tris(pyrazolyl)borate titanium complexes, Tp′TiCl 2 (OAr) and Tp*TiMe 2 (OAr) [Tp ) HB(pyrazolyl) 3 , Tp* ) HB(3,5-Me 2 -pyrazolyl) 3 ; Ar ) Ph, 2,6-Me 2 C 6 H 3 , 2,6i Pr 2 C 6 H 3 ], were prepared, and their structures were determined by X-ray crystallography. These complexes exhibited from moderate to remarkable catalytic activities for ethylene polymerization in the presence of MAO; TpTiCl 2 (OPh) exhibited the highest catalytic activity for ethylene polymerization. The cationic Ti(IV)-methyl complex, [Tp*TiMe(O-2,6-Me 2 C 6 H 3 )] + [MeB(C 6 F 5 ) 3 ] -• (THF) 2 , polymerizes ethylene to give polyethylene with a uniform molecular weight distribution, clearly indicating that the cationic Ti(IV) species plays an essential role as the active species.

Air-and moisture-sensitive compounds were handled under an inert N 2 atmosphere, using standard Schlenk line techniques and an MBraun Unilab or triple MBraun LabMaster glovebox when required.