Gas-Phase Energetics of Reductive Elimination from a Palladium(II) N-Heterocyclic Carbene Complex

被引：50

作者：

Couzijn, Erik P. A. ^{[1
]}

Zocher, Eva ^{[1
]}

Bach, Andreas ^{[1
]}

Chen, Peter ^{[1
]}

机构：

[1] ETH, Organ Chem Lab, CH-8093 Zurich, Switzerland

来源：

CHEMISTRY-A EUROPEAN JOURNAL | 2010年 / 16卷 / 18期

关键词：

carbene ligands; C-C coupling; density functional calculations; mass spectrometry; palladium; COLLISION-INDUCED DISSOCIATION; CROSS-COUPLING REACTIONS; LIGAND-BINDING ENERGIES; DENSITY FUNCTIONALS; TRANSITION; KINETICS; TRANSMETALATION; THERMOCHEMISTRY; MOLECULES; MECHANISM;

D O I：

10.1002/chem.200902929

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

Energy-resolved collision-induced dissociation experiments using tandem mass spectrometry are reported for an phenylpalladium N-heterocyclic carbene (NHC) complex. Reductive elimination of an NHC ligand as a phenylimidazolium ion involves a barrier of 30.9(14) kcal mol(-1), whereas competitive ligand dissociation requires 47.1(17) kcal mol(-1). The resulting three-coordinate palladium complex readily undergoes reductive C-C coupling to give the phenylimidazolium pi complex, for which the binding energy was determined to be 38.9(10) kcal mol(-1). Density functional calculations at the M06-L//BP86/TZP level of theory are in very good agreement with experiment. In combination with RRKM modeling, these results suggest that the rate-determining step for the direct reductive elimination process switches from the C-C coupling step to the fragmentation of the resulting a complex at low activation energy.

引用

页码：5408 / 5415

页数：8

共 80 条

[51] N-heterocyclic carbene-transition metal complexes:: Spectroscopic and crystallographic analyses of π-back-bonding interactions [J].