Safranine-T Triplet-State Quenching by Modified Silica Nanoparticles

VALERIA B. ARCE; SONIA G. BERTOLOTTI; FERNANDO J. V. E. OLIVEIRA; CLAUDIO AIROLDI,; MÓNICA C. GONZALEZ; PATRICIA E. ALLEGRETTI; DANIEL O. MÁRTIRE

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Lugar: Washington; Año: 2011 vol. 115 p. 18122 - 18130

1932-7447

Modified silica nanoparticles (NPs) were obtained by esterification of the silanol groups of fumed silica nanoparticles with 4-hydroxymethyl-N,N-dimethylbenzenamine. These particles werecharacterized by Fourier transform infrared spectroscopy, 13C and 29Si nuclear magnetic resonance, thermogravimetry, X-ray photoelectron spectroscopy, transmission electron microscopy with energydispersive spectroscopy, and measurement of the specific surface area. Laser flash photolysis experiments at the excitation wavelength of 532 nm were performed with safranine-T and NP suspensions in acetonitrile. Comparative experiments of safranine-T with solutions of 4-hydroxymethyl-N,N-dimethylbenzenamine and two other related alcohols were performed. Evidence for the triplet safranine-T H-abstraction from the organic group of the particles is obtained. The electron transfer from the organic group to the triplet excited states of safranine-T also takes place, as shown by the absorption traces obtained at 50 μs after the laser shot.