Reduction of dioxygen by an NADH model compound and 1,1′-dimethylferrocene catalysed by acids in homogeneous and heterogeneous systems
Abstract
An acid-stable NADH model compound, 10-methyl-9,10-dihydroacridine (AcrH2) and 1,1′-dimethylferrocene [Fe(C5H4Me)2] are oxidized by dioxygen in the presence of HClO4 in acetonitrile and water. The acid-catalysed two-electron and four-electron reductions of dioxygen by AcrH2 and [Fe(C5H4Me)2], respectively, take place more efficiently in the heterogeneous systems using solid acid catalysts [alumina, silica–alumina, HY-type zeolite, and solid superacids (ZrO2 and Fe2O3 treated with H2SO4)] activated by calcination at various temperatures. Mechanisms of both the homogeneous and heterogeneous reduction of dioxygen by AcrH2 and [Fe(C5H4Me)2] are discussed.