Unusually stable palladium(IV) complexes: detailed mechanistic investigation of C-O bond-forming reductive elimination

J Am Chem Soc. 2005 Sep 21;127(37):12790-1. doi: 10.1021/ja0541940.

Abstract

This communication describes the synthesis of a family of unusually stable palladium(IV) complexes containing two chelating 2-phenylpyridine ligands and two benzoates. These complexes undergo clean C-O bond-forming reductive elimination upon heating, and the mechanism of this catalytically relevant process has been studied in detail. Solvent effects, crossover experiments, Eyring plots (which show DeltaS of -1.4 +/- 1.9 and 4.2 +/- 1.4 in CDCl3 and DMSO, respectively), and Hammett analysis (which shows rho = -1.36 +/- 0.04 upon substitution of the para-benzoate substituent) all suggest that reductive elimination does not proceed via initial dissociation of a benzoate ligand. Instead, an unusual mechanism involving pre-equilibrium dissociation of the N-arm of the phenylpyridine ligand is proposed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Crystallography, X-Ray
  • Models, Molecular
  • Molecular Structure
  • Organometallic Compounds / chemical synthesis
  • Organometallic Compounds / chemistry*
  • Oxidation-Reduction
  • Palladium / chemistry*

Substances

  • Organometallic Compounds
  • Palladium