In this work, we present the cyclohexane oxidation catalyzed by the mononuclear 1,10-phenantroline Cu(II) complexes: [Cu(phen)(3)]Cl-2 center dot 7H(2)O (1), [Cu(phen)(2)Cl]Cl center dot 5H(2)O (2), [Cu(phen)Cl-2] (3), using hydrogen peroxide as oxidant, in acetonitrile:water (3.5:1) solution. The reactions were carried out at temperatures ranging from 25 degrees C to 70 degrees C. All complexes were able to oxidize cyclohexane into cyclohexanol and cyclohexanone with low to moderate yields. Adipic acid was also formed in the reaction. The highest conversion was obtained with the system [Cu(phen)(2)Cl]Cl/H2O2/70 degrees C, with 67% total yield. Furthermore, these complexes were also able to oxidize toluene at room temperature. (C) 2009 Elsevier B.V. All rights reserved.