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 = H-2, Zn) bearing quadruply positive charges associates with an anionic metal-ore cluster (SiW12O404-) to form a supramolecular complex in aqueous solution. The spectral evolution and Job's plots reveal that the aggregates contain equal numbers of the cationic porphyrins and the anionic SiW12O404-. 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 O-2, and more of O-2 is reduced to H2O at potential where the SiW12O404- is in reduced state. (C) 2000 Elsevier Science S.A. All rights reserved.