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.

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Tautomerism of several thioamides was studied by mass spectrometry. The analysis of the corresponding mass spectra allowed some fragmentations to be assigned to specific tautomers and heats of tautomerization to be determined through temperature effects and electron energy studies. Experimental determinations were strongly supported by theoretical calculations. AM1 semi-empirical results indicate that the thioamide-thioimidol equilibrium can be studied by mass spectrometry. Also, additional evidence was obtained regarding tautomerism occurrence between neutral species.

β-Ketonitrile tautomeric copolymers have demonstrated tunable hydrophilicity/hydrophobicity properties according to surrounding environment, and mechanical properties similar to those of human bone tissue. Both characteristic properties make them promising candidates as biomaterials for bone tissue engineering. Based on this knowledge we have designed two scaffolds based on β-ketonitrile tautomeric copolymers which differ in chemical composition and surface morphology. Two of them were nanostructured, using an anodized aluminum oxide (AAO) template, and the other two obtained by solvent casting methodology. They were used to evaluate the effect of the composition and their structural modifications on the biocompatibility, cytotoxicity and degradation properties. Our results showed that the nanostructured scaffolds exhibited higher degradation rate by macrophages than casted scaffolds (6 and 2.5% of degradation for nanostructured and casted scaffolds, respectively), a degradation rate compatible with bone regeneration times. We also demonstrated that the β-ketonitrile tautomeric based scaffolds supported osteoblastic cell proliferation and differentiation without cytotoxic effects, suggesting that these biomaterials could be useful in the bone tissue engineering field.