INIFTA   05425
INSTITUTO DE INVESTIGACIONES FISICO-QUIMICAS TEORICAS Y APLICADAS
Unidad Ejecutora - UE
artículos
Título:
Generation of Chemisorbed Benzyl Radicals on Silica Nanoparticles
Autor/es:
VALERIA B. ARCE; JANINA A. ROSSO; FERNANDO J. V. E. OLIVEIRA; CLAUDIO AIROLDI; DELIA B. SORIA; MÓNICA C. GONZALEZ; PATRICIA E. ALLEGRETTI; DANIEL O. MÁRTIRE
Revista:
PHOTOCHEMISTRY AND PHOTOBIOLOGY
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Año: 2010 vol. 86 p. 1208 - 1214
ISSN:
0031-8655
Resumen:
Functionalized silica nanoparticles (NP) were obtained byesterification of the silanol groups of fumed silica nanoparticleswith benzyl alcohol. These particles were characterized byFourier transform infrared spectroscopy, 13C and 29Si NMRspectroscopy, thermogravimetry, total organic carbon, Brunauer–Emmett–Teller analysis, UV-visible spectroscopy, andtransmission electron microscopy. NP suspensions inwater ⁄ acetonitrile mixtures were used as quenchers of benzophenone(BP) phosphorescence in time-resolved experiments atthe excitation wavelength of 266 nm. The phosphorescencesignals obtained in the presence of the nanoparticles werefitted to biexponential decays. Both decays were accelerated inthe presence of increasing amounts of NP. A model, includingthe reversible adsorption of BP on the NP, which wassupported by computer simulations accounts for the observedresults. Laser flash-photolysis experiments with excitation at266 nm of NP suspensions in water/acetonitrile in the presenceof BP generated benzyl radicals that were attached to thesilica surface. These radicals were detected at their absorptionmaxima (320 nm) by transient optical techniques.