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Metalloporphyrins in Polymeric Matrices, Micelles, and Vesicles, IV. Photochemical and Peroxide Oxidations of Magnesium Octaethylporphyrinate in the Presence of Polymeric and Monomeric Imidazole Derivatives
Author(s) -
Fuhrhop JürgenHinrich,
Kerkhoff AloisBernhard,
Besecke Siegmund
Publication year - 1982
Publication title -
liebigs annalen der chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0170-2041
DOI - 10.1002/jlac.198219820514
Subject(s) - chemistry , imidazole , photochemistry , singlet oxygen , peroxide , quenching (fluorescence) , monomer , benzoyl peroxide , copolymer , micelle , polymer chemistry , photooxygenation , oxygen , fluorescence , organic chemistry , polymer , aqueous solution , physics , quantum mechanics
Abstract Magnesium octaethylporphyrin (MgOEP) in foils of polystyrene was oxygenated quantitatively by visible light and oxygen to yield the corresponding formylbilinate. In poly[1‐phenylethyleneco‐1‐(1‐imidazolyl)ethylene] (95:5 or 78:22 mol %) the quantitative formation of MgOEP cation radical was observed. The photooxygenation was fully suppressed in this copolymer. This is explained with a physical quenching of singlet oxygen by imidazole. — Oxidation of MgOEP with benzoyl peroxide in the presence of imidazole yields either octaethyl‐5‐imidazolylporphyrin or 10‐benzoyloxy‐octaethyl‐5,15‐diimidazolylporphyrin and other highly substituted porphyrins. The latter produces only one absorption band (λ max ≈ 560 nm) in the visible range and yields isoporphyrins (λ max ≈ 900 nm) in a reversible reaction with an excess of benzoyl peroxide. The same reaction with the imidazole‐containing copolymer leads to a covalent binding of MgOEP. The reversible formation of an isoporphyrin is observed with molecular oxygen.