K. Schiwon et al., POTENTIAL PHOTOSENSITIZERS FOR PHOTODYNAMIC THERAPY .4. PHOTOPHYSICALAND PHOTOCHEMICAL PROPERTIES OF AZAPORPHYRIN AND AZACHLORIN DERIVATIVES, Journal of photochemistry and photobiology.B, Biology, 23(2-3), 1994, pp. 239-243
The photophysical and photochemical properties of a 5-azaprotoporphyri
n derivative ([5]AZPP), a zinc-15-azaporphyrin derivative (Zn-[15]AZID
P) and an E-Z isomeric mixture of a 5-azachlorin derivative ([5]AZCH)
were studied in various solvents. The quantum yields of fluorescence P
HI(F)0, S1-T1 intersystem crossing PHI(T)0 and singlet oxygen (1DELTA(
g) formation PHI(DELTA) were measured and the Stern-Volmer constants f
or the quenching of the S1 states by oxygen and the rate constants of
quenching of O2(1DELTA(g)) by the different azaporphyrinoid compounds
were obtained. The fluorescence quantum yield (PHI(F)0 = 0.23), the st
rong absorption in the red (LAMBDA(max) = 674 nm, epsilon(max) = 66 00
0 M-1 cm-1) and the high value of the quantum yield for singlet oxygen
(1DELTA(g)) formation (PHI(DELTA) = 0.65) observed for [5]AZCH recomm
end azachlorin derivatives as potential markers and photosensitizers f
or tumour therapy.