Abstract

The effect of substituent nature and position on a series of late transition metal catalysts based on nickel (A–D) was investigated practically and theoretically. Catalyst A bearing isopropyl groups on the ortho position showed the highest activity while for the ortho and para chlorine substituted catalysts B–D insignificant activities were observed. These experimental results were confirmed by theoretical study on the (pre)catalysts. Based on that, thermodynamics, atomic/molecular effective parameters such as bond distances, bond angles, band gap or chemical hardness, charge of Mulliken on Ni center, electronic chemical potential, global electrophilicity index and also activation energy of the pre-catalyst through the alkylation were calculated. To pursue the steric and electronic effects of substituent on the axial and equatorial sites of active center, electronic density, electron location function, localized orbital locator graphs as topological properties were studied. As a result, complex A with lower activation energy for alkylation, higher stability, greater Mulliken charge on Ni center and high electronic density around the active center was found as a highly active catalyst. In addition, polymerization conditions such as polymerization temperature and ethylene pressure showed significant effect on the catalysts productivity and branching density of the produced polyethylene.

中文翻译：

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α-二胺Ni基催化剂上氯取代基的拓扑和电子性质

摘要

取代基性质和位置的一系列后过渡金属催化剂的基于镍的影响（甲- d）中的溶液几乎和理论研究。在邻位带有异丙基的催化剂A表现出最高的活性，而对于邻氯和对氯取代的催化剂B – D观察到微不足道的活动。这些实验结果通过对（预）催化剂的理论研究得到证实。基于此，热力学，原子/分子有效参数（例如键距，键角，带隙或化学硬度），Mulliken在Ni中心的电荷，电子化学势，整体亲电指数以及通过该催化剂的预催化剂的活化能计算烷基化。为了研究取代基对活性中心的轴向和赤道位点的空间和电子效应，研究了电子密度，电子定位函数，局部轨道定位图作为拓扑性质。结果，复数A具有较低的烷基化活化能，较高的稳定性，在Ni中心具有更大的Mulliken电荷以及在活性中心附近具有较高的电子密度是一种高活性催化剂。另外，聚合条件如聚合温度和乙烯压力对所生产的聚乙烯的催化剂生产率和支化密度显示出显着影响。