作者:Dirong Gong、Wen Liu、Tao Chen、Zhong-Ren Chen、Kuo-Wei Huang
DOI:10.1016/j.molcata.2014.08.005
日期:2014.12
Chromium (III) complexes, Cr1, [2,6-((Bu2PNH)-Bu-t)(2)C5H4N]CrCl3; Cr2, [2,6-(Ph2PNH)(2)C5H4N]CrCl3; Cr3, [2-((Bu2PNH)-Bu-t)C5H4N]CrCl3 THF; Cr4, [6-((Bu2PNH)-Bu-t)C5H4N-2-CH2NEt2]CrCl3; Cr5, [6-((Bu2PNH)-Bu-t)C5H4N-2-C3H2N2]CrCl3; Cr6, [6-((Bu2PNH)-Bu-t)C5H4N-2-(3,5-Me-2)C3H2N2]CrCl3; Cr7, [6-((Bu2PNH)-Bu-t)C5H4N-2-(3,5-iPr(2))C-3 H2N2]CrCl3; Cr8, [6-((Bu2PNH)-Bu-t)C5H4N-2-(3,5-Ph-2)C3H2N2]CrCl3, bearing a family of neutral PN3-type pincer ligands have been prepared. The molecular structure of Cr2 was further elucidated by the X-ray crystallographic analysis, showing an octahedral geometry. Treatment of these complexes with MAO or alkylaluminum led to catalysts with moderate activities (about 10(5) g (PE)/Cr(mol)h) for ethylene polymerization, affording exclusively linear low molecular weight solid PE without any detectable oligomers. Among Cr1-Cr8, the highest activity was achieved for Cr1/MAO at room temperature with production of PE with highest molecular weight, indicating that replacement of both Bu-t groups in Cr1 with Ph groups, or one (PBu2)-Bu-t with the N (imine) arm, resulted in a lower catalytic activity and lower M-w. (C) 2014 Elsevier B.V. All rights reserved.