Multicopper models for the laccase active site: effect of nuclearity on electrocatalytic oxygen reduction

Inorg Chem. 2014 Aug 18;53(16):8505-16. doi: 10.1021/ic501080c. Epub 2014 Jul 29.

Abstract

Cu complexes of 2,2'-dipicolylamine (DPA) were prepared and tested as electrocatalysts for the oxygen reduction reaction (ORR). To study the effect of multinuclearity on the ORR, two Cu-DPA units were connected with a flexible linker, and a third metal-binding pocket was installed in the ligand framework. ORR onset potentials and the diffusion-limited current densities of di- and tricopper complexes of DPA derivatives were found to be comparable to those of the simpler Cu-DPA system. Electrochemical analyses, crystallographic data, and metal-substitution studies suggested that Cu complexes of DPA derivatives reacted with O2 via a binuclear intermolecular pathway but that the Cu center in the third binding site did not participate in the ORR process. This study highlights the viability of Cu-DPA complexes to mimic the T3-site of laccase, and serves as a guide for designing future laccase models.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amines / chemistry*
  • Amines / metabolism
  • Catalysis
  • Catalytic Domain
  • Copper / chemistry*
  • Copper / metabolism
  • Electrochemical Techniques
  • Laccase / chemistry*
  • Laccase / metabolism
  • Models, Molecular
  • Molecular Structure
  • Organometallic Compounds / chemical synthesis
  • Organometallic Compounds / chemistry*
  • Organometallic Compounds / metabolism
  • Oxidation-Reduction
  • Oxygen / chemistry*
  • Oxygen / metabolism
  • Picolinic Acids / chemistry*
  • Picolinic Acids / metabolism

Substances

  • 2,2'-dipicolylamine
  • Amines
  • Organometallic Compounds
  • Picolinic Acids
  • Copper
  • Laccase
  • Oxygen