Large Kinetic Isotope Effects for the Protonolysis of Metal–Methyl Complexes Are Not Reliable Mechanistic Indicators
作者:Valerie J. Scott、Jay A. Labinger、John E. Bercaw
DOI:10.1021/om200432b
日期:2011.8.22
several palladium and platinum methyl complexes (with release of methane) had suggested the possibility that observation of an unusually large kinetic isotope effect, consistent with significant contributions from quantum mechanical tunneling, might be diagnostic of a mechanism involving direct protonation of the metal–methyl bond, as opposed to one proceeding via a metal hydride intermediate. By extension
Hydrogen Tunneling in Protonolysis of Platinum(II) and Palladium(II) Methyl Complexes: Mechanistic Implications
作者:John E. Bercaw、George S. Chen、Jay A. Labinger、Bo-Lin Lin
DOI:10.1021/ja807427d
日期:2008.12.31
Platinum(II) and palladium(II) complexes are well-known to catalyze the partial oxidation of alkanes. Herein, we present experimental evidence that tunneling occurs in the protonolysis of M(II)-CH(3) (M = Pt, Pd) model systems. We propose that there may be a connection between the observation of tunneling and a protonolysis mechanism involving direct protonation of the M-C bond and that tunneling may
众所周知,铂 (II) 和钯 (II) 配合物可催化烷烃的部分氧化。在这里,我们提出了隧道发生在 M(II)-CH(3) (M = Pt, Pd) 模型系统的质子分解中的实验证据。我们提出,隧道效应的观察与涉及 MC 键直接质子化的质子分解机制之间可能存在联系,并且通过 Pt(II) 和 Pd(II) 进行的甲烷的亲电 CH 活化也可以预期隧道效应。 sigma 复合体的直接质子损失。
Transmetalation of Alkyl Ligands from Cp*(PMe<sub>3</sub>)IrR<sup>1</sup>R<sup>2</sup>to (cod)PtR<sup>3</sup>X
作者:Landon J. Durak、Jared C. Lewis
DOI:10.1021/om400289s
日期:2013.6.10
Transmetalation of alkyl and carboxylate ligands between Cp*(PMe3)Ir complexes and d(8) Pt and Pd complexes is described. Studies on the scope and kinetics of this reaction support a mechanism in which carboxylate dissociation from the Pt or Pd center precedes alkyl transfer from Ir. Subsequent reaction of the resulting Pt or Pd alkyl complex enables functionalization of the hydrocarbyl ligands and suggests new opportunities for catalytic, nondirected C-C and C-H bond functionalization reactions.