meso-Tetrakis(4-N-benzylpyridyl)porphyrin and its supramolecular complexes formed with anionic metal–oxo cluster: spectroscopy and electrocatalytic reduction of dioxygen

The research results show that MTBPyP (meso-tetrakis(4-N-benzylpyridyl)porphyrin, M=H2, Zn) bearing quadruply positive charges associates with an anionic metal-oxo cluster (SiW12O40 4−) to form a supramolecular complex in aqueous solution. The spectral evolution and Jobʹs plots reveal that the aggregates contain equal numbers of the cationic porphyrins and the anionic SiW12O40 4−. The association is accompanied by significant changes in the Soret band of the individual porphyrins. The 1:1 supramolecular complex [CoTBPyP][SiW12O40] may serve as an electrocatalyst for electrocatalytic reduction of O2, and more of O2 is reduced to H2O at potential where the SiW12O40 4− is in reduced state.