Synthesis and structure of a chromium(III) complex coordinated by 1,1′-Bi-2-naphtholate ligands and its catalytic activity for ethylene polymerization

Reaction of CrCl3(THF)3 with rac-Li2(binol) (binol=1,1′-bi-2-naphtholate) gave a new chromium(III) complex, [Li(THF)]3[Cr(binol)3]·3(toluene) (1). The X-ray crystallographic structure of 1 revealed its propeller-like structure similar to those of the reported rare earth analogues. The complex 1 showed moderate catalytic activities for ethylene polymerization upon activation with modified methylaluminoxane (MMAO) and with diethylaluminum chloride. When 1 was supported on the silica surface, activity increased to two times of homogeneous 1/MMAO system.