INIFTA   05425
INSTITUTO DE INVESTIGACIONES FISICO-QUIMICAS TEORICAS Y APLICADAS
Unidad Ejecutora - UE
artículos
Título:
Photochemical and photophysical properties of lumazine in aqueous solutions
Autor/es:
M. PAULA DENOFRIO; THOMAS ANDRÉS HÉCTOR; ANDRÉ M. BRAUN; ESTHER OLIVEROS; CAROLINA LORENTE
Revista:
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
Referencias:
Año: 2008 vol. 200 p. 282 - 286
ISSN:
1010-6030
Resumen:
Lumazine (pteridine-2,4(1H,3H)-dione, LU) was investigated for its efficiency of singlet-oxygen (1O2) production and quenching in aqueous solution. The quantum yield of 1O2 production (FD) was determined by measurements of the 1O2 luminescence in the near-infrared upon continuous excitation of the sensitizer. Values of FD are sensitive to the pH and were found to be 0.44±0.01 and 0.080±0.004 in acidic and alkaline media, respectively. The photochemical stability of LU was investigated under different pH conditions, in the presence and in the absence of O2. The photochemical consumption of LU in aqueous solution at room temperature under irradiation at 350 nm was followed by UV-visible spectrophotometry and HPLC. Values of the quantum yields of LU disappearance are low, indicating that LU is rather photostable under physiological conditions.