A series of tetrabutylammonium (TBA) salts of the transition metal mono-substituted silicotungstates [SiW 11 M(H 2 O)O 39 ] nÀ , M = Co II , Fe III , Mn III , (SiW 11 M) were explored as homogeneous catalysts for the oxidation of geraniol and styrene with H 2 O 2 . The most active homogeneous catalysts (SiW 11 Co and SiW 11 Fe) were immobilized onto an amine-functionalized SBA-15 (aptesSBA-15) and the resulting composites were characterized using several techniques (FT-IR, FT-Raman, UV-Vis/DRS, elemental analysis, powder XRD, SEM and N 2 adsorption-desorption isotherms). The catalytic performance of the new composites SiW 11 Co@aptesSBA-15 and SiW 11 Fe@aptesSBA-15 was investigated under similar experimental conditions to those used for homogeneous counterparts. 2,3-Epoxygeraniol and benzaldehyde were the main products obtained from geraniol and styrene oxidation, respectively, for all the catalysts. SiW 11 Co and SiW 11 Co@aptesSBA-15 showed to be the most active catalysts for the oxidation of geraniol and styrene.The recyclability of the composite SiW 11 Co@aptesSBA-15 was investigated for three reaction cycles. The stability of the composites was confirmed using several techniques after catalytic cycles.

No abstract

No abstract

Nitric oxide (NO) is one of the smallest endogenous molecules with particularly interesting aspects roles in biological systems, despite its toxicological potential. Solid carriers have potential biomedical interest in the delivery of exogenous NO for anti-bacterial, anti-thrombic and wound healing applications. In this work, we prepared nanoporous materials from clay based solids, of montmorillonite type, with the main goal of studying its potential in the field of storage and release of nitric oxide for therapeutic applications.Materials were characterized by X-ray diffraction, nitrogen adsorption at À196 C, TG-DSC and chemical analysis. The kinetic data for the nitric oxide storage and release, in selected materials, was obtained in gas and liquid phases. The released amounts of NO in the liquid phase were within the biological range and, for some materials, a slow release kinetics was obtained with, inclusively, an almost direct relation between the released fraction and time. Toxicological assays with HeLa cells indicated that the materials have low cytotoxicity.

No abstract