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PHOTOPHYSICAL PROPERTIES OF meso‐TETRAPHENYLPORPHYRIN and SOME meso‐TETRA(HYDROXYPHENYL)PORPHYRINS
Author(s) -
Bonnett R.,
McGarvey D. J.,
Harriman A.,
Land E. J.,
Truscott T. G.,
Winfield UJ.
Publication year - 1988
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1988.tb02820.x
Subject(s) - photochemistry , porphyrin , singlet oxygen , chemistry , tetraphenylporphyrin , flash photolysis , tetra , quenching (fluorescence) , triplet state , phosphorescence , fluorescence , singlet state , quantum yield , excited state , reaction rate constant , oxygen , molecule , medicinal chemistry , kinetics , organic chemistry , physics , quantum mechanics , nuclear physics
— The o‐, m‐, and p‐isomers of 5, 10, 15, 20‐ tetra(hydroxyphenyl)‐porphyrin have been of recent interest as potential second‐generation sensitisers in tumour phototherapy. Fluorescence spectroscopy, nanosecond laser flash photolysis and pulse radiolysis have been used to characterise the singlet and triplet excited states of tetraphenylporphyrin and the o, m‐, and p‐isomers of tetra(hydroxyphenyl)porphyrin. This has included evaluation of fluorescence yields and lifetimes, triplet spectra, lifetimes, oxygen quenching rate constants, extinction coefficients, and yields and singlet oxygen yields. Whilst the fluorescence quantum yields were low, the triplet yields were all 0.7 ± 10% and the singlet oxygen yields 0.6 ± 10%: all these parameters are in the ranges shown by other efficient porphyrin photosensitisers. The similar photophysical properties found for these compounds suggest that their differing tumour sensitising efficiencies are likely to be due to other factors.