Synthesis, structure and catecholase activity of dinuclear copper and zinc complexes with an N(3)-ligand

J Inorg Biochem. 2002 Jul 25;91(1):190-8. doi: 10.1016/s0162-0134(02)00459-2.

Abstract

The preparation and characterization of dinuclear [M(II)(dbcat)(idpa)](2) (M[double bond]Zn (1), Cu (3); dbcat[double bond]3,5-di-tert-butylcatecholate; idpa[double bond]3,3'-iminobis(N,N-dimethylpropylamine)) complexes are described. Crystallographic characterization of the complex [Cu(II)(dbcat)(idpa)](2) has shown that the co-ordination geometry around copper(II) ions is distorted square pyramidal (triclinic, P-1, a=10.576(1) A, b=11.927(1) A, c=12.621(1) A, alpha=77.89(1) degrees, beta=88.65(1) degrees, gamma=70.21(1) degrees, V=1462.7(2) A(3), Z=2, R=0.0387). Both 1 and 3 were suitable catalysts for the catalytic oxidation of dbcatH(2) to dtbq (dtbq=3,5-di-tert-butyl-1,2-benzoquinone) with dioxygen at ambient conditions in good yields. However, on the basis of kinetic studies the copper- and zinc-catalyzed reactions showed different mechanisms. In the first case valence tautomerism [Cu(II)(dbcat)(idpa)]<==>[Cu(I)(dbsq)(idpa)] precedes the reaction with O(2), while with the zinc complex metal-bound catecholate reacts directly with O(2) with the formation of free superoxide anion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Catechols / chemistry*
  • Catechols / metabolism
  • Copper / chemistry*
  • Crystallography, X-Ray
  • Electron Spin Resonance Spectroscopy
  • Molecular Structure
  • Oxidation-Reduction
  • Oxidoreductases / chemistry*
  • Oxidoreductases / metabolism
  • Solutions
  • Zinc / chemistry*

Substances

  • Catechols
  • Solutions
  • Copper
  • Oxidoreductases
  • Zinc