Exploring Electronic and Steric Effects on the Insertion and Polymerization Reactivity of Phosphinesulfonato Pd<sup>II</sup>Catalysts
作者:Boris Neuwald、Laura Falivene、Lucia Caporaso、Luigi Cavallo、Stefan Mecking
DOI:10.1002/chem.201301365
日期:2013.12.23
products through NMR spectroscopy. Differences in the homo‐ and copolymerization of ethylene and MA regarding catalyst activity and stability over time, polymer molecular weight, and polar co‐monomer incorporation were investigated. DFT calculations were performed on the main insertion steps for both monomers to rationalize the effect of the ligand substitution patterns on the polymerization behaviors of
制备了13种不同的对称和不对称的膦磺酸磺钯钯配合物([(X 1 -Cl)-μ‐M} n ],M = Na,Li,1 = X(P ^ O)PdMe)(见图1)。确定了(MeO)2 1-py,(i PrO)2 1-lut,(MeO,Me2) 1-lut,(MeO)3 1-lut,CF3的相应吡啶或二甲基吡啶复合物的固态结构1‐lut和Ph 1‐lut。用AgBF 4提取氯化物后获得的催化剂X 1的反应活性通过确定首次和连续MA插入的速率常数以及通过NMR光谱法分析β-H和其他分解产物来量化丙烯酸对甲基丙烯酸(MA)的含量。研究了乙烯和MA的均聚和共聚在催化剂活性和随时间的稳定性,聚合物分子量以及极性共聚单体掺入方面的差异。在两种单体的主要插入步骤上进行了DFT计算,以使配体取代方式对配合物聚合行为的影响合理化。对数据的全面分析表明:1)缺电子催化剂聚合活性更高,但也观察到快速失活;2)双邻位取代催化剂(MeO)21和(MeO)3