Allosteric Effects in Ethylene Polymerization Catalysis. Enhancement of Performance of Phosphine-Phosphinate and Phosphine-Phosphonate Palladium Alkyl Catalysts by Remote Binding of B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>
作者:Alison M. Wilders、Nathan D. Contrella、Jessica R. Sampson、Mingfang Zheng、Richard F. Jordan
DOI:10.1021/acs.organomet.7b00815
日期:2017.12.26
positive charge on the Pd center. This effect does not result in the large increase in the chain transfer rate (Rtransfer) and concomitant reduction in PE molecular weight seen in previous studies of analogous (PO)PdRL catalysts that contain phosphine-arenesulfonate ligands, because of the operation of a dissociative chain transfer process, which is inhibited by the increased charge at Pd.
B(C 6 F 5)3与(PPO)PdMeL(L =吡啶或二甲基吡啶)或(PPO)PdMe} 2的乙烯聚合催化剂的远程结合,这些催化剂包含膦-芳烃次膦酸酯或膦-芳烃膦酸酯配体(PPO – = [1 -PAr 2 -2-PR'O 2 -Ph] -:Ar = R'= Ph(1a); Ar = Ph,R'= OEt(1b); Ar = Ph,R'= O i Pr(1c) ; Ar = 2-OMe-Ph,R'= O i Pr(1d))显着提高了催化剂活性和聚乙烯(PE)产品的分子量。在最有利的情况下,原位(转化1D)PDME(PY),以游离碱加合物 1D ·B(C 6 ˚F 5)3 } PDME增加了从9.8乙烯聚合活性来5700千克摩尔-1 ħ -1和中号Ñ的从9030到99200 Da(80°C,410 psi)的PE产品。X射线结构数据,配体不稳定性趋势以及BF 3活化的比较研究表明,这些变构作用主要是电子起源的。B(C