Isolation of neutral mononuclear copper complexes stabilized by two cyclic (alkyl)(amino)carbenes

J Am Chem Soc. 2014 Apr 30;136(17):6235-8. doi: 10.1021/ja502521b. Epub 2014 Apr 17.

Abstract

Two (cAAC)2Cu complexes, featuring a two-coordinate copper atom in the formal oxidation state zero, were prepared by reducing (Et2-cAAC)2Cu(+)I(-) with metallic sodium in THF, and by a one-pot synthesis using Me2-cAAC, Cu(II)Cl2, and KC8 in toluene in a molar ratio of 2:1:2, respectively. Both complexes are highly air and moisture sensitive but can be stored in the solid state for a month at room temperature. DFT calculations showed that in these complexes the copper center has a d(10) electronic configuration and the unpaired electron is delocalized over two carbene carbon atoms. This was further confirmed by the EPR spectra, which exhibit multiple hyperfine lines due to the coupling of the unpaired electron with (63,65)Cu isotopes, (14)N, and (1)H nuclei.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkylation
  • Amines / chemical synthesis
  • Amines / chemistry*
  • Coordination Complexes / chemical synthesis
  • Coordination Complexes / chemistry*
  • Copper / chemistry*
  • Cyclization
  • Electron Spin Resonance Spectroscopy
  • Methane / analogs & derivatives*
  • Methane / chemical synthesis
  • Methane / chemistry
  • Models, Molecular
  • Oxidation-Reduction

Substances

  • Amines
  • Coordination Complexes
  • carbene
  • Copper
  • Methane