Several Au(III)/Schiff-base complexes were studied and proven to be effective catalysts for oxidative carbonylation of methanol to generate dimethyl carbonate (DMC). Effects of Schiff-base ligands, promoters, and promoter pole ratio to Au(III)/Schiff-base complexes on catalytic activity were studied. When the reaction was carried out at a methanol/Au(III) molar ratio of 5060:1, an [AuCl(2)(phen)]Cl/KI (phen = 1,10-phenanthroline) ratio of 1:4, a CO/O(2) pressure of 2:1, and a temperature of 120 degrees C for 3 h, the conversion, selectivity, and TOF value of the model reaction were 10.8%, 98%, and 138.9 h(-1), respectively. The catalyst was characterized by FTIR, UV-vis, (1)H NMR, and cyclic voltammetry. The oxidation state of gold during the reaction and the role of KI were discussed using data on electrochemical experiments and ESI-MS. [AuI(2)(phen)](+) was considered an intermediate in the reaction. A plausible Au(III)/Au(I) catalytic cycle mechanism was proposed. (C) 2011 Elsevier B.V. All rights reserved.