Ethylene polymerization by PN3-type pincer chromium(III) complexes
KAUST DepartmentKAUST Catalysis Center (KCC)
Physical Sciences and Engineering (PSE) Division
Chemical Science Program
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AbstractChromium (III) complexes, Cr1, [2,6-(tBu2PNH) 2C5H4N]CrCl3; Cr2, [2,6-(Ph 2PNH)2C5H4N]CrCl3; Cr3, [2-(tBu2PNH)C5H4N]CrCl3 THF; Cr4, [6-(tBu2PNH)C5H4N-2- CH2NEt2]CrCl3; Cr5, [6-(tBu 2PNH)C5H4N-2-C3H2N 2]CrCl3; Cr6, [6-(tBu2PNH)C 5H4N-2-(3,5-Me2)C3H 2N2]CrCl3; Cr7, [6-(tBu 2PNH)C5H4N-2-(3,5-iPr 2)C3H2N2]CrCl3; Cr8, [6-(tBu2PNH)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 105 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 tBu groups in Cr1 with Ph groups, or one PtBu2 with the N (imine) arm, resulted in a lower catalytic activity and lower M w. © 2014 Elsevier B.V.
SponsorsWe are grateful for the generous financial support from King Abdullah University of Science and Technology, the Natural Science Foundation of China (Grant Nos. 21304050 and 21302170), the Natural Science Foundation of Ningbo (Grant No. 2014A610109), K. C. Wong Magna Fund and Start-up Fund in Ningbo University.
Is Supplemented ByGong, D., Liu, W., Chen, T., Chen, Z.-R., & Huang, K.-W. (2015). CCDC 862186: Experimental Crystal Structure Determination [Data set]. Cambridge Crystallographic Data Centre. https://doi.org/10.5517/ccxy5gg