IITEMA   27339
INSTITUTO DE INVESTIGACIONES EN TECNOLOGIAS ENERGETICAS Y MATERIALES AVANZADOS
Unidad Ejecutora - UE
artículos
Título:
Photophysics and photochemistry of porphyrin core PAMAM dendrimers. Excited states interaction with quinones
Autor/es:
ERNESTO M. ARBELOA; HERNÁN MONTEJANO; RAQUEL E. HERNÁNDEZ RAMÍREZ; CARLOS M. PREVITALI; M. PAULA MILITELLO; IRINA V. LIJANOVA; SONIA G. BERTOLOTTI
Revista:
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
Editorial:
ELSEVIER SCIENCE SA
Referencias:
Lugar: Amsterdam; Año: 2020 vol. 388
ISSN:
1010-6030
Resumen:
Quenching of excited states of the meso-substituted tetraphenyl porphyrins withPAMAM branches, and one with PAMAM generation 1 peripherally-modified withthiazole groups by p-benzoquinones, were studied in DMF solution. Fluorescencelifetime measurements evidence a static component in the quenching process. Thedynamic quenching rate constants were close to the diffusional limit except for the case of duroquinone. Apparent association constants of the porphyrin compounds with the quinones were determined by comparison of static and dynamic measurements of fluorescence quenching. The ground state interaction is very weak with the exception of tetrachlorobenzoquinone. The triplet state decay kinetics and the transient absorption spectra in the presence of the quinones were determined by laser flash photolysis. Triplet quenching rate constants were lower than those of singlet quenching. An electron transfer mechanism was proposed to explain the results. The long-time transient absorption spectra were assigned to the radical cation of the dyes. Relative radical yields were determined and a dependence on the side chains and the quencher was observed.