Phthalocyanine metal complexes: Versatile catalysts for selective oxidation and bleaching

Iron and other metal phthalocyanine complexes can mediate both selective oxidation and bleaching reactions depending on the choice of oxidant. Olefins, phenols, condensed aromatics can efficiently be oxidized to valuable products by (BuOOH)-Bu-t. The use of H2O2 leads to a different kind of reactivity providing efficient systems for catalytic degradation of recalcitrant pollutants and bleaching. The discovery of remarkable catalytic properties of mu-nitrido diiron phthalocyanine complexes exemplified by mild catalytic oxidation of methane in water at near-ambient conditions is of especial significance. This emerging type of oxidation catalysts has a great potential for the development. In this context, a combinatorial approach might be particularly fruitful. First, different macrocyclic ligands can be used, e. g. phthalocyanines, porphyrins, porphyrazines, corroles, corrolazines, etc. to produce either symmetrical dimers with the same ligand or unsymmetrical dimers having two different macrocyclic ligands. Secondly, a number of transition metals (Fe, Mn, Ru, Cr, V, Ti, etc.) can be used for the preparation of homoleptic or heteroleptic dimers having the same or different metals. Finally, several single bridging atoms can be used including O, N, C. The great variability of possible metal, ligand, bridging atom combinations might provide a large variety of complexes with different and tunable catalytic properties. (C) 2010 Elsevier B.V. All rights reserved.