Nucleophilicity of Alkyl Zirconocene and Titanocene Precatalysts, and Kinetics of Activation by Carbenium Ions and by B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>
作者:Guillaume Berionni、Hiroaki Kurouchi、Lucien Eisenburger、Herbert Mayr
DOI:10.1002/chem.201602452
日期:2016.8.1
tritylium ions, and triarylborane B(C6F5)3 were measured spectrophotometrically. The rate constants correlate linearly with the electrophilicity parameter E of the benzhydrylium and tritylium ions employed, allowing us to determine the σ‐nucleophilicities of the metal–carbon bond of several zirconocenes and titanocenes. Bridging, substitution, metal, and ligand effects on the rates of metal–alkyl
分光光度法测定了苯甲酸铵离子,三苯甲基离子和三芳基硼烷B(C 6 F 5)3活化甲基和苄基金属茂预催化剂的动力学。速率常数与亲电参数E线性相关苯甲酰和三苯甲酰离子的数量,使我们能够确定几种锆茂和钛茂金属的金属-碳键的σ亲核性。研究了桥接,取代,金属和配体对金属-烷基键裂解速率(M = Zr,Ti)的影响,并利用结构-反应性相关性预测了茂金属离子对的生成动力学,茂金属离子对是其中的活性催化剂。并在受阻的路易斯对催化中是高度亲电的路易斯酸。