Photo-oxygenation of meso-tetraphenylporphyrin derivatives: the influence of the substitution pattern and characterization of the reaction products

Citation
Ams. Silva et al., Photo-oxygenation of meso-tetraphenylporphyrin derivatives: the influence of the substitution pattern and characterization of the reaction products, J PORPHYR P, 2(1), 1998, pp. 45-51
Citations number
21
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Chemistry
Journal title
JOURNAL OF PORPHYRINS AND PHTHALOCYANINES
ISSN journal
1088-4246 → ACNP
Volume
2
Issue
1
Year of publication
1998
Pages
45 - 51
Database
ISI
SICI code
1088-4246(199801/02)2:1<45:POMDTI>2.0.ZU;2-9
Abstract
The photo-oxidation reactions of several meso-tetraphenylporphyrins have be en studied in order to ascertain the chemical stability of this class of co mpounds towards singlet oxygen. The 2,6-disubstituted ones showed an excell ent stability, whilst this is not the case for other porphyrins with differ ent substitution pattern on the phenyl rings. This parallels what has been previously found using mono-oxygenated donors. The steric effects in protec ting the macrocycle seems to be predominant over the electronic ones; even with electron-donating groups in the 2,6-positions, e.g. methoxy groups, th e porphyrin macrocycle was not degraded. The reaction on the beta-tetrabrom inated meso-tetraphenylporphyrin also proceeded easily and yielded a bilino ne derivative. The structures of the final products were all elucidated by mass,H-1 and C-13 NMR spectroscopy. (C) 1998 John Wiley & Sons, Ltd.