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Rapid and Selective Oxidation of Metallosulfophthalocyanines Prior to Their Usefulness as Precatalysts in Oxidation Reactions
Author(s) -
d’Alessandro Nicola,
Tonucci Lucia,
Bressan Mario,
Dragani Luana K.,
Morvillo Antonino
Publication year - 2003
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200200620
Subject(s) - chemistry , oxidizing agent , catalysis , hydrogen peroxide , metal , photochemistry , biliverdin , catalytic oxidation , medicinal chemistry , ligand (biochemistry) , ring (chemistry) , thioanisole , inorganic chemistry , organic chemistry , heme , heme oxygenase , biochemistry , receptor , enzyme
Two metallosulfophthalocyanines, RuPcS and FePcS, used in many catalytic oxidation reactions, were readily oxidized by hydrogen peroxide or monopersulfate, under acidic or neutral conditions in water, to form novel metal complexes derived from the facile oxidation of the PcS ring. Meso‐nitrogen‐oxide derivatives and metal‐biliverdin‐like derivatives were identified among the products at early reaction times, whereas at longer times fragmentation of the phthalocyanine ring occurred, with formation of sulfophthalimide and metal complexes containing the resulting tridentate ligand. The oxidative degradation of the MPcS complexes has been investigated by ESI‐MS, UV/Vis‐NIR and 1 H, 13 C and 15 N NMR spectroscopy . These rapidly formed, coordinatively unsaturated complexes represent the dominant species in oxidizing media, at least in the case of the Ru derivative, and must be the real catalyst precursors in previously published oxidation reactions using MPcS complexes. The oxidative degradation reactions occurred with selective mono‐denitrogenation of one meso‐nitrogen atom and formation of ammonia, thus recalling the celebrated selective degradation of heme to verdoheme and/or biliverdin and CO. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)