Navegando por Autor "Ardisson, José D."

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Effect of iron precursor on the Fenton-like activity of Fe2O3 /mesoporous silica catalysts prepared under mild conditions
(Applied Catalysis B: Environmental, 2014-01) Tronto, Jairo; Coelho, Jakelyne V.; Guedes, Marina S.; Prado, Roberta G.; Ardisson, José D.; Pereira, Márcio C.; Oliveira, Luiz C. A.
Fe2O3/mesoporous silica catalysts were prepared by adding Fe2+ or Fe3+ ions, as an iron precursor, during the synthesis of silica gel. Low angle XRD data showed that both iron precursors affected the hexagonal ordered arrays of silica, which were more perturbed by Fe2+ than by Fe3+ ions, as confirmed by TEM images. Based on the Mössbauer spectroscopy, XPS, EPR and NH3-TPD data was possible to identify the iron species supported on the silica matrix are constituted of hematite and maghemite. The iron precursor strongly changed the specific area of the materials from 1406 m^2 g^−1, in pure silica sample, to 1165 and 799 m^2 g^−1 for the Fe3-MS and Fe2-MS samples, respectively, but the pore size distribution was maintained in the range of 15–40 Å in both samples. These Fe-containing silica nanoparticles showed good catalytic activity to degrade methylene blue in aqueous medium. However, the Fe3-MS sample was more active than the Fe2-MS sample because the iron in the first is more exposed, which facilitated the accessibility to the active Fenton-like sites. These synthesized samples showed to be more stable against the Fe leaching than samples prepared by simple impregnation of hematite on the silica surface. This was because the strong interaction of iron and silica matrix was achieved by adding iron in the course of the synthesis of silica gel.
Sais de tetrafenilfosfônio e tris( 1,10- fenantrolina) ferro( ii) de complexos aniônicos de dibutilestanho( iv) com ditiocarbimatos: síntese, caracterização e atividade antifúngica
(Química Nova, 2016-06) Bottega, Fernanda C.; Oliveira, Marcelo R. L.; Rubinger, Mayura M. M.; Bellato, Carlos R.; Ardisson, José D.; Zambolim, Laercio
Six new salts of organometallic complexes of tin(IV) with the general formulae: (Ph4P)2[Sn(Bu)2(RSO2N=CS2)2] and [Fe(phen)3][Sn(Bu)2(RSO2N=CS2)2] [Ph4P = tetraphenylphosphonium, R = CH3 (1), C2H5 (2) and C4H9 (3); Fe(phen)3 = tris(1,10-phenanthroline)iron(II), R = CH3 (4), C2H5 (5) and C4H9 (6)] were synthetized from potassium dithiocarbimates (RSO2N=CS2K2.H2O) in reaction with dichlorobis-n-butyltin(IV) and tetraphenylphosphonium chloride (1-3) in N,N-dimethylformamide or tris(1,10-phenanthroline)iron(II) (4-6) in methanol. The new compounds were characterized by elemental analysis of Fe and Sn, and by vibrational, Mössbauer and nuclear magnetic resonance of 1H, 13C and 119Sn spectroscopies. High-resolution mass spectra in the negative and positive modes were also obtained. The elemental analyses and the exact masses obtained for the cations and the complex anions were consistent with the proposed formulae. The Mössbauer spectroscopic data were consistent with the presence of tin(IV) with coordination numbers between 4 and 5 (compounds 1-6), and of hexacoordinated iron(II) (compounds 4-6). The 1H and 13C NMR spectra presented all the expected signals for the cations and anions, and the signals observed in the 119Sn NMR spectra indicated an equilibrium between tetra- and pentacoordination around the tin atoms in solution. The in vitro activity of the new compounds was evaluated against Botrytis cinerea and Colletotrichum acutatum.
Síntese e caracterização de novos organometálicos de estanho (iv) com ligantes ditiocarbimatos e sua ação acceleradora na vulcanização de borracha nitrílica
(Química Nova, 2016-08) Bottega, Fernanda C.; Oliveira, Marcelo R. L.; Sérvulo, Vanessa Pio; Visconte, Leila L. Y.; Ardisson, José D.; Rubinger, Mayura M. M.
This paper describes the synthesis of four new organotin compounds of general formula: (Ph4P)[Sn(Cy)3(RSO2N=CS2)] [Ph4P = tetraphenylphosphonium cation, Cy = cyclohexyl, R = C6H5 (1), 4-ClC6H4 (2), 4-BrC6H4 (3) and 4-IC6H4 (4)]. They were obtained by the reaction between four different potassium N-R-sulfonyldithiocarbimate salts and tricyclohexyltin chloride in methanol, and were isolated as tetraphenylphosphonium salts. The elemental analyses of C, H, N and the data of high-resolution mass spectrometry were consistent with the proposed formulae. The 119Sn NMR spectra and 119Sn Mössbauer spectroscopic data were consistent with the presence of tetracoordinated tin(IV) species in solution and in the solid state. The electrolytic molar conductance and the integration curves in the 1H NMR spectra are in accord with the 1:1 proportion between the tetraphenylphosphonium cations and the complex anions. The activity of the new compounds in the vulcanization of nitrile rubber was evaluated and the results were compared to those achieved with the commercial accelerators: N-tert-butyl-2-benzothiazolesulfenamide (TBBS), tetramethylthiuram disulfide (TMTD) and zinc diethyldithiocarbamate (ZEDC).
Syntheses, characterization and antifungal activity of novel dimethylbis(N-R-sulfonyldithiocarbimato)stannate(IV) complexes
(Elsevier Journal of Molecular Structure, 2017-02-05) Bomfim Filho, Lucius F. O.; Oliveira, Marcelo R. L.; Miranda, Liany D. L.; Vidigal, Antonio E. C.; Guilardi, Silvana; Souza, Rafael A. C.; Ellena, Javier; Ardisson, José D.; Zambolim, Laércio; Rubinger, Mayura M. M.
Four new complexes of the general formula: Ph4P)2[Sn(CH3)2(RSO2NCS2)2], where Ph4P = tetraphenylphosphonium cation and R = CH3, (1), CH3CH2 (2), C6H5 (3), 4-FC6H4 (4), were prepared by the reaction of the appropriate potassium N-R-sulfonyldithiocarbimates, K2(RSO2NCS2), and tetraphenylphosphonium chloride with dimethyltin dichloride. The compounds 1–4 were characterized by 1H, 13C and 119Sn NMR, 119Sn Mössbauer, vibrational spectroscopy and by elemental analyses of C, H, N and Sn. The crystal structure of 1 was determined by X-ray diffraction techniques. The in vitro antifungal activity of the tin(IV) complexes were evaluated against the fungi Rhizoctonia solani and Botrytis cinerea by the Poisoned food test. The new compounds showed comparable activities to the fungicides manzate and ziram.
Synthesis, characterization and biocidal activity of new organotin complexes of 2-(3-oxocyclohex-1-enyl)benzoic acid
(European Journal of Medicinal Chemistry, 2010-03) Maia, José R. da S.; Vieira, Flaviana T.; Lima, Geraldo M. de; Speziali, Nivaldo L.; Ardisson, José D.; Rodrigues, Leonardo; Correa Junior, Ary; Romero, Oscar B.
The reaction of 1,3-cyclohexadione with 2-aminobenzoic acid has produced the 2-(3-oxocyclohex-1-enyl)benzoic acid (HOBz). Subsequent reactions of the ligand with organotin chlorides led to [Me2Sn(OBz)O]2 (1), [Bu2Sn(OBz)O]2 (2), [Ph2Sn(OBz)O]2 (3), [Me3Sn(OBz)] (4), [Bu3Sn(OBz)] (5) and [Ph3Sn(OBz)] (6). All complexes have been fully characterized. In addition the structure of complexes (2) and (4) have been authenticated by X-ray crystallography. The biological activity of all derivatives has been screened against Cryptococcus neoformans and Candida albicans. In addition we have performed toxicological testes employing human kidney cell. The complexes (3), (5) and (6) displayed the best values of inhibition of the fungus growing, superior to ketoconazole. Compound (5) presented promising results in view of the antifungal and cytotoxicity assays.