(Pyrazol-1-yl)carbonyl palladium complexes as catalysts for ethylene polymerization reaction
作者:Hosana D. Mkoyi、Stephen O. Ojwach、Ilia A. Guzei、James Darkwa
DOI:10.1016/j.jorganchem.2012.10.036
日期:2013.1
Reactions of two equivalents of 3,5-(dimethylpyrazol-1-yl)-4-methoxy-1-carbonyl}benzene (L1), 3,5-(dimethylpyrazol-1-yl)-4-ethoxy-1-carbonyl}benzene (L2), 3,5-(dimethylpyrazol-1-yl)-4-hexyloxy-1-carbonyl}benzene (L3), and 3,5-(dimethylpyrazol-1-yl)-4-dodecycloxy-1-carbonyl}benzene (L4) with one equivalent of [Pd(NCMe)(2)Cl-2] produced the corresponding monometallic complexes, [Pd(L1)(2)Cl-2) (1), [Pd(L2)(2)Cl-2) (2), [Pd(L3)(2)Cl-2) (3) and [Pd(L4)(2)Cl-2) (4) in good yields. Solid state structures of 2 and 4 confirmed the monodentate character of L1-L4 and trans configuration of the palladium complexes. Activation of 1-4, and the furanyl and thiophenyl carbonyl pyrazolyl palladium complexes: [Pd((Me)pzCOfn)(2)Cl-2] (5), [Pd((Me)pzCOth)(2)Cl-2] (6), [Pd((tBu)pzCOfn)(2)Cl-2] (7) and [Pd((tBu)pzCOfn)(2)Cl-2] (8) (fn = furan, th = thiophene) with MAO produced catalysts for the polymerization of ethylene with moderate activities; forming linear high density polyethylene. The structure of the complexes had a significant effect on both the activity of the catalysts and nature of the polymers obtained. (C) 2012 Elsevier B. V. All rights reserved.