The kinetics of the reactions of oxoiron(IV) (FeO 2+ ) with phenol, nitrobenzene, m-, o-, and p-nitrophenol in 1 M HClO 4 was investigated by the stopped-flow technique. The rate constants of these reactions decrease with increasing the one-electron reduction potentials of the corresponding radical cations of the substrates and with the Hammett parameter of the NO 2 group in the phenol ring. A reaction mechanism is proposed, which accounts for the observed trends and for the nature of the reaction products.

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Butoxylated silica nanoparticles (BSN) were prepared by esterification of the silanol groups of fumed silica nanoparticles with butanol. These particles were characterized by FTIR, BET, TEM, and TOC. BSN suspensions in water:acetonitrile mixtures were used as quenchers of benzophenone (BP) phosphorescence in time-resolved experiments at the excitation wavelengths of 266 and 337 nm. The phosphorescence signals obtained in the presence of the nanoparticles were fitted to biexponential decays. Both decays were accelerated in the presence of increasing amounts of BSN. A model including the reversible adsorption of BP on BSN and supported by computer simulations accounts for the observed results.