• Copper;
  • Allylic peroxylation;
  • Coordination polymers;
  • Radical reactions;
  • Oxidation


The copper complexes [Cu(4-MeBPI)(OAc)] (4), [Cu(4-Me-10-tBuBPI)(OAc)] (5) and [Cu(BTI)(OAc)] (6) [BPI = 1,3-bis(2-pyridylimino)isoindole, BTI = 1,3-bis(2-thiazolylimino)isoindole] were prepared by reaction of the protio ligands with copper(II) acetate. Compounds 4 and 6 were characterized by X-ray diffraction, establishing distorted square-planar coordination geometries of the copper ions. Two monoclinic modifications of 6 (6a and 6b) were found, both crystallizing in the space group P21/c, but possessing different cell parameters. In contrast to 6a, which is monomeric in the crystal, the second monoclinic modification 6b has a more complicated crystal structure, which is composed of both monomeric complex units such as those found in 6a and infinite chains of coordination polymers. The copper atoms in the polymeric chains of 6b display fivefold coordination and a ligand polyhedron that is an intermediate form between a trigonal-bipyramidal and a square-pyramidal geometry. The allylic peroxylation of cyclohexene with tBuOOH (70% aqueous solution) catalyzed by 4 and 6 (0.17 mol %) gave tert-butylperoxy-3-cyclohexene with selectivities of 86% and 80% (based on cyclohexene) and turnover frequencies of 63 h−1 and 18 h−1, respectively. The peroxylation reaction is thought to proceed according to a Haber−Weiss radical chain mechanism. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)