Microporous dinuclear copper(II) trans-1,4-cyclohexanedicarboxylate:: heterogeneous oxidation catalysis with hydrogen peroxide and X-ray powder structure of peroxo copper(II) intermediate

A two-dimensional microporous dinuclear copper(II) trans-1,4-cyclohexanedicarboxylate, [Cu-2(II,III) (OOCC6H10OCOO)(2)] (.) H2O (1), can act as a heterogeneous catalyst for selective oxidations of various alcohols with hydrogen peroxide. Complex 1 catalyzed the selective oxidations of 2-propanol, cyclohexanol, benzyl alcohol, 2-octanol, and 1-octanol with > 99% selectivities in a heterogeneous system. A green-colored active intermediate, H-2[Cu-2(II,II)(OOCC6H10COO)(2)(O-2)] (.) H2O (2), observed in the reaction of 1 with a 20-fold excess H2O2 in acetonitrile was characterized by elemental analysis, TG/DTA, magnetic susceptibility, FT-IR, diffuse reflectance UV-vis, EPR, X-ray powder diffraction (XRPD), resonance Raman spectra, BET surface area, pore size distribution, and nitrogen occlusion measurements. The molecular structure of 2 was determined from XRPD data and refined by the Rietveld method. The microporous structure of 2 was constructed by intramolecular bridging of mu-1,2-trans Cu-OO-Cu species between two-dimensional [Cu-2(O2CC6H10CO2)] layers. The complex 2 was the first example of the microporous copper(II) peroxo complex for heterogeneous oxidation catalysis. (C) 2004 Elsevier Inc. All rights reserved.