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This paper describes a comparative study of laccase-based biocathodes containing different redox mediator species, namely porphyrin, ferrocene, osmium, and ruthenium complexes were immobilized onto carbon platforms entrapped in an electropolymerized polypyrrole matrix. Ferrocenium hexafluorophosphate (Fc), an Iron (III) porphyrin (FeTMPyP), a ruthenium complex [Ru(byp) 2 Cl 2 ], and an osmium complex [Os(byp) 2 Cl 2 ] were employed as redox mediators and have been characterized by cyclic voltammetry. Methanol/O 2 biofuel cell tests employing the biocathodes showed that they provide higher output power as compared with other systems. In the best conditions, the maximum power densities reached values around 81 ± 4 and 71 ± 3 μW cm −2 for [Ru(bpy) 2 Cl 2 ] and [Os(bpy) 2 Cl 2 ] at pH 4.5, respectively.

As metaloporfirinas de segunda geração (MePs), cloreto de [5,10,15,20-tetraquis(pentafluorofenil)porfirinaferro(III)], FeP, e cloreto de [5,10,15,20-tetraquis(pentafluorofenil)porfirinamanganês(III)], MnP, foram covalentemente ancoradas em suportes aminofuncionalizados, com o objetivo de preparar catalisadores sólidos seletivos para a oxidação de compostos orgânicos. Montmorillonita K10 funcionalizada com 3-aminopropiltrietoxissilano (Mont1) ou com 3-cloropropiltrietoxissilano seguida por reação com 1,6-diaminoexano (Mont2), e sílica gel funcionalizada com 3-aminopropiltrietoxissilano (Sil1) ou modificada com 3-cloropropiltrietoxissilano seguida por reação com 1,6-diaminoexano (Sil2) foram preparadas e caracterizadas por UV-Vis, IR, EPR, TGA e difratometria de raios X. As atividades catalíticas das MePs imobilizadas nestes suportes foram investigadas na oxidação de (Z)-cicloocteno, cicloexano e estireno por iodosilbenzeno (PhIO) ou H 2 O 2 . Os sistemas estudados foram catalisadores eficientes da oxidação de todos os substratos, especialmente utilizando PhIO como oxidante. Não se observou lixiviamento das MePs dos suportes, indicando que a ligação covalente é um método muito eficiente para a imobilização de catalisadores. As FePs imobilizadas foram catalisadores mais eficientes que as correspondentes MnPs, mesmo quando imidazol foi empregado como um co-catalisador para as MnPs ancoradas. Embora os rendimentos de produtos oxidados utilizando H 2 O 2 tenham sido mais baixos que aqueles obtidos com PhIO, alguns sistemas heterogêneos envolvendo MePs foram mais eficientes que as correspondentes MePs em solução, tanto em termos de rendimento de produto quanto de seletividade.The second-generation metalloporphyrins (MePs) [5,10,15,20-tetrakis(pentafluorophen yl)porphyrin iron(III)] chloride, FeP, and [5,10,15,20-tetrakis(pentafluorophenyl)porphyrin manganese(III)] chloride, MnP, were covalently attached to aminofunctionalized supports, with a view to preparing selective solid catalysts for the oxidation of organic compounds. Montmorillonite K10 functionalized with 3-aminopropyltriethoxysilane (Mont1) or modified with 3-chloropropyltriethoxysilane followed by reaction with 1,6-diaminohexane (Mont2), and silica gel functionalized with 3-aminopropyltriethoxysilane (Sil1) or modified with 3-chloropropyltriethoxysilane followed by reaction with 1,6-diaminohexane (Sil2) were synthesized and characterized by UV-Vis and IR spectroscopies, EPR, TGA, and X-ray diffractometry. The catalytic activities of the MePs immobilized on these supports were investigated for the oxidation of (Z)-cyclooctene, cyclohexane and styrene by PhIO or H 2 O 2 . The studied systems were efficient catalysts for the oxidation of all substrates, especially when PhIO was the oxidant. There was no MeP leaching from the supports, indicating that covalent binding is a very efficient method for catalyst immobilization. The immobilized FePs were more efficient catalysts than the corresponding MnPs, even when imidazole was employed as a cocatalyst for the supp...

Tetrahydrofuran lignans represent a well-known group of phenolic compounds capable of acting as antiparasitic agents. In the search for new medicines for the treatment of Chagas disease, one promising compound is grandisin which has shown significant activity on trypomastigote forms of Trypanosoma cruzi. In this work, the in vitro metabolism of grandisin was studied in the pig cecum model and by biomimetic phase I reactions, aiming at an ensuing a preclinical pharmacokinetic investigation. Although grandisin exhibited no metabolization by the pig microbiota, one putative metabolite was formed in a biomimetic model using Jacobsen catalyst. The putative metabolite was tested against T. cruzi revealing loss of activity in comparison to grandisin.

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