Abstract

A simplified synthetic method was initiated to prepare the corresponding nickel complexes NiL₂ (I–III) with direct condensation of mono(imino)pyrroles (L¹–L³) and nickel dichloride, the structures and methyl methacrylate (MMA) catalytic polymerization behavior of this series of mono(imino)pyrrole nickel complexes were presented. The mono(imine)pyrrole ligands and the corresponding nickel complexes were determined by ¹H NMR, ¹³C NMR, IR and MS, etc. Complexes I and III were further characterized by X-ray crystal diffraction (CIF files CCDC nos. 1890965 (I), 1890964 (III)). Both of the structures showed that the ligand chelated to nickel with 2 : 1 molar ratio. The systematic studies were focused on the relationship between the catalytic behavior of these complexes for MMA polymerization and catalyst structure, reaction time, reaction temperature, and ratio of monomer with catalyst. The optimum reaction conditions of the molar ratio of monomer to catalyst is of 1200 : 1, the polymerization temperature of 100°C, time of 10 h, the nickel complex with two bulky substituents on the o-position of phenyl ring linked with imine showed excellent catalytic activities for MMA polymerization (4.791 × 10⁴ g mol^–1 h^–1), high molecular weight (M_n = 65.873 × 10³ g mol^–1), and narrow molecular mass distribution (polymer dispersity index = 3.9877), and azodiisobutyronitrile acted as co-catalyst during MMA polymerization.

中文翻译：

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单（亚氨基）吡咯配体的镍（II）配合物：制备，结构和MMA聚合行为。

摘要

开始一种简化的合成方法，以单（亚氨基）吡咯（L ¹ -L ³）和二氯化镍直接缩合制备相应的镍配合物NiL ₂（I – III），其结构和甲基丙烯酸甲酯（MMA）催化聚合行为介绍了该系列的单（亚氨基）吡咯镍配合物。单（亚胺）吡咯配体和相应的镍配合物通过¹ H NMR，¹³ C NMR，IR和MS等确定。配合物I和III通过X射线晶体衍射进一步表征（CIF文件CCDC No.1890965（我），1890964（III））。两种结构均表明配体以2∶1的摩尔比与镍螯合。系统研究集中在这些配合物用于MMA聚合反应的催化行为与催化剂结构，反应时间，反应温度以及单体与催化剂的比例之间的关系上。单体与催化剂的摩尔比的最佳反应条件为1200：1，聚合温度为100°C，时间为10h，在与亚胺连接的苯环的o位上带有两个大取代基的镍络合物显示出MMA聚合具有出色的催化活性（4.791×10 ⁴ g mol ^–1 h ^–1），高分子量（M _n= 65.873×10 ³ g mol ^–1），分子量分布窄（聚合物分散指数= 3.9877），偶氮二异丁腈在MMA聚合过程中充当助催化剂。