Polymerization of Isoprene Promoted by Aminophosphine(ory)-Fused Bipyridine Cobalt Complexes: Precise Control of Molecular Weight and <i>cis</i>-1,4-<i>alt</i>-3,4 Sequence
作者:Junyi Zhao、Huafeng Chen、Wenxin Li、Xiaoyu Jia、Xuequan Zhang、Dirong Gong
DOI:10.1021/acs.inorgchem.8b00270
日期:2018.4.2
as characterizations of the X-ray diffractions for complexes Co4 and Co6, which revealed the cobalt center is expectedly pentacoordinated in a distorted trigonal bipyramidal configuration with a prolonged Co—O(═P) bond. In combination with MMAO, complex Co2 was highly active in cis-1,4-alt-3,4 enchained polymerization. The hemilabile nature of O═P is possible for the alternating η4-cis-1,4 and η2-3
配体N-(二烷基或芳基膦基)-(2,2'-联吡啶)-6-胺(L1,芳基= Ph; L2,烷基= t Bu; L3,烷基=金刚烷基(Ad))以及相应的被氧化的设计N-(2,2'-联吡啶-6-基)-P,P-二烷基或芳基次膦酰胺(L4,芳基= Ph; L5,烷基= t Bu; L6,烷基= Ad)同系物二氯化钴。形成的配合物的结构通过IR和元素分析以及配合物C o 4的X射线衍射表征和C o 6,表明钴中心被预期以具有延长的Co-O(═P)键的扭曲三角双锥体构型五配位。与MMAO结合,复合物Co2在顺-1,4- alt -3,4链式聚合反应中具有很高的活性。O = P的hemilabile性质可能的是,交替的η 4 -顺式-1,4-和η 2 -3,4-协调,和插入在金属-碳键接踵而至。与ALET组合2氯,每个复合物的CO4,CO5和CO6在观察到的聚合速率常数(k obs = 0.1531 L mol