We show that highly efficient acetaldehyde-to-acetic acid oxidation is achieved in a diluted FeCl3-acetonitrile solution (5-100 mu M), which proceeds rather rapidly and follows the enzymatic-like Michaelis-Menten kinetics. Interestingly, by adjusting the concentration of FeCl3, we are able to accelerate or shut down the oxidation process conveniently. Based on the catalytic results, spectroscopic evidences and successive DFT calculations, a reactant-initiated, putative mononuclear non-heme iron-oxygen complex, [FeCl(MeCN)(4)(O)](2+), is proposed as the active oxidizing species to conduct the room temperature reaction with relatively high TOF values (similar to 1.2 s(-1)). Finally, the putative iron-oxygen complexes are employed to the selective oxidation of benzyl alcohol under ambient conditions. (C) 2013 Elsevier B.V. All rights reserved.