Biaryl Reductive Elimination Is Dramatically Accelerated by Remote Lewis Acid Binding to a 2,2′-Bipyrimidyl–Platinum Complex: Evidence for a Bidentate Ligand Dissociation Mechanism

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• 作者：Allegra L. Liberman-Martin ; Daniel S. Levine ; Wenjun Liu ; Robert G. Bergman ; T. Don Tilley
• 刊名：Organometallics
• 出版年：2016
• 出版时间：April 25, 2016
• 年：2016
• 卷：35
• 期：8
• 页码：1064-1069
• 全文大小：420K
• 年卷期：0
• ISSN：1520-6041

文摘

The silicon and zinc Lewis acids Si(cat)₂ (cat = catecholato), Si(cat^F)₂ (cat^F = tetrafluorocatecholato), and Zn(C₆F₅)₂ bind to the remote ligand site of a 2,2′-bipyrimidyl–platinum diaryl complex. This platinum complex provides a platform to systematically evaluate electronic and reactivity differences triggered by Lewis acid binding. The electron density of the bipyrimidine ligand is substantially depleted upon Lewis acid binding, as evidenced by UV–vis spectroscopy and cyclic voltammetry. Biaryl reductive elimination studies allowed quantification of the effect of Lewis acid binding on reactivity, and Lewis acid binding accelerated reductive elimination rates by up to 8 orders of magnitude. Kinetics experiments in combination with DFT studies support an unusual mechanism featuring complete dissociation of the Lewis acid-coordinated bidentate bipyrimidine ligand prior to reductive elimination.