Chromium complexes coordinated with chelating disiloxane-1,3-diamido ligands as catalyst precursors for ethylene polymerization

Abstract

Reaction of CrCl 2 with 0.5 equivalents of Li 4[(N t BuSiMe 2) 2O] 2 ( 1) gave a new chromium(II) complex, Cr 2[(N t BuSiMe 2) 2O] 2 ( 2). Similar reaction of CrCl 3 with 1 yielded the corresponding chromium(III) complex, Cr 2[(N t BuSiMe 2) 2O] 3 ( 3). The dinuclear structure of 3 was revealed by X-ray crystallography, in which the disiloxanediamido ligand can be regarded as an N, N-bidentate ligand. The complexes 2 and 3 showed relatively high catalytic activities for ethylene polymerization upon activation with diethylaluminum chloride.