MnII—A fascinating oxidation catalyst: Mechanistic insight into the catalyzed oxidative degradation of organic dyes by H2O2

The use of simple MnII ions as efficient catalyst precursors for the oxidation of different highly stable organic dyes using H2O2 as an environmentally benign oxidant under mild reaction conditions, is presented. The role of a series of aromatic dyes in the in situ formation and stabilisation of the active catalyst was studied in detail using stopped-flow techniques and UV–Vis detection. DFT calculations were employed to predict the nature of the role of the substrate in the stabilisation of highly reactive MnII intermediates. Furthermore, low-temperature EPR measurements were performed in order to characterize the in situ formed catalytically active MnIVO intermediate responsible for the fast and versatile oxidation of organic dyes in aqueous solution.

Graphical abstractThe use of simple MnII ions as efficient catalyst precursors for the oxidation of various highly stable organic dyes using H2O2 as an environmentally benign oxidant under mild reaction conditions, is presented. The role of a series of aromatic dyes in the in situ formation and stabilisation of the active catalyst was studied in detail using stopped-flow techniques and UV–Vis detection.Figure optionsDownload full-size imageDownload as PowerPoint slide