This paper first discloses that two heteroleptic 8-quinolinolato iron(III) complexes (Qa(1) Qb(2)Fe(III), Qa(2)Qb(1)Fe(III)) could be synthesized conveniently via the coordination of FeCl2 center dot 6H(2)O with 2 equivalents of 5,7-dichloro-8-hydroxyquinoline (Qb) or 5-chloro-8-hydroxyquinoline (Qa) under N-2 and then 1 equivalent of Qa or Qb under air. In comparison with the two homoleptic counterparts (Qa(3)Fe(III) and Qb(3)Fe(III)), the proposed heteroleptic Q(3)Fe(III) complexes possessed similar coordination features to the Qb(3)Fe(III) one but showed similar catalysis performances to the Qa(3)Fe(III) one in the oxygenation of cyclohexane to cyclohexanol and cyclohexanone by hydrogen peroxide (H2O2) in acetonitrile. More importantly, both heteroleptic Q(3)Fe(III) complexes showed a better accelerating effect on this reaction and provided a slightly higher conversion than the Qa(3)Fe(III) and especially Qb(3)Fe(III) ones. Furthermore, this predominance in catalytic activity was more strikingly apparent upon both-catalyzed oxygenations of benzene, toluene, ethylbenzene or thioanisole by H2O2. This should be due to a structurally distorted effect of the heteroleptic Q(3)Fe(III) complexes that is induced by the different in ligand environment, as supported by DFT B3LYP/6-311G (d) calculation. Based the present reaction and UV vis spectral characterization results, a free radical mechanism for the present catalysis system was proposed. (C) 2015 Elsevier B.V. All rights reserved.