Artigos
URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11800
Navegar
9 resultados
Resultados da Pesquisa
Item Nickel complexes with phosphines and N-R-sulfonyldithiocarbimates ligands: New antifungals for the control of Hemileia vastatrix and Phakopsora pachyrhizi(Inorganica Chimica Acta, 2019-02-24) Vidigal, Antonio E. C.; Rubinger, Mayura M. M.; Queiroz, Luan F. de; Silva, Lucas F. da; Zambolim, Laércio; Guilardi, Silvana; Souza, Rafael A. C.; Ellena, Javier; Wetler, Emiliana B.; Oliveira, Marcelo R. L.Nickel(II) complexes of general formula [Ni(RSO2N = CS2)(PPh3)2] (2a–h) or [Ni(RSO2N = CS2)dppe] (3a–h), where R = methyl (a), ethyl (b), butyl (c), octyl (d), phenyl (e), 4-isopropylphenyl (f), 4-tert-butylphenyl (g), 2-naphthyl (h), PPh3 = triphenylphosphine and dppe = 1,2-bis(diphenylphosphine)ethane were prepared, from which six are new substances (2f–h and 3f–h). The new compounds were characterized by elemental analysis of C, H, N and Ni, and by IR, UV–Vis and 1H, 13C and 31P NMR spectroscopies. The data were consistent with the formation of square planar nickel(II) complexes with mixed ligands, what was confirmed by single crystal X-ray diffraction studies on compounds 2f and 2h. These complexes present intramolecular NiHC anagostic interactions. All complexes inhibited the germination of Hemileia vastatrix and Phakopsora pachyrhizi, the causal agents of devastating diseases on soybean and coffee cultures. The most active compounds presented IC90 values as low as 405 µM against H. vastatrix, and 280 μM against P. pachyrhizi. Thus, the title compounds are target molecules for the development of new agrochemicals against the Asian soybean rust and Coffee leaf-rust diseases.Item Centrosymmetric resonance-assisted intermolecular hydrogen bonding chains in the enol form of β-diketone: Crystal structure and theoretical study(Journal of Molecular Graphics and Modelling, 2016-07) Teixeira, Róbson R.; Pereira, Wagner L.; Ellena, Javier A.; Paixão, Drielly A.; Guilardi, Silvana; Franca, Eduardo F.Isobenzofuran-1(3H)-ones (phtalides) are heterocycles that present a benzene ring fused to a γ-lactone functionality. This structural motif is found in several natural and synthetic compounds that present relevant biological activities. In the present investigation, the 3-(2-hydroxy-4,4-dimethyl-6-oxocyclohexen-1-yl)isobenzofuran-1(3H)-one was characterized by single-crystal X-ray analysis. In the crystal structure, there are two molecules per asymmetric unit. One of them exhibits resonance assisted hydrogen bonds (RAHBs). Semi-empirical and DFT calculations were performed to obtain electronic structure and π-delocalization parameters, in order to better understand the energy stabilization of RAHBs in the crystal packing of the studied molecule. The structural parameters showed good agreement between theoretical and experimental data. The theoretical investigation revealed that the RAHBs stabilization energy is directly related to the electronic delocalization of the enol form fragment. In addition, RAHBs significantly affected the HOMO and charge distribution around the conjugated system.Item Tetraphenylphosphonium allyldithiocarbimates derived from Morita- Baylis-Hillman adducts: Synthesis, characterization, crystal structure and antifungal activity(Journal of Molecular Structure, 2016-02-15) Tavares, Eder C.; Rubinger, Mayura M. M.; V. Filho, Eclair; Oliveira, Marcelo R. L.; Piló-Veloso, Dorila; Ellena, Javier; Guilardi, Silvana; Souza, Rafael A. C.; Zambolim, LaércioBotrytis blight is a very destructive disease caused by Botrytis spp., infecting flowers, trees, vegetables and fruits. Twelve new compounds were prepared by the reaction of potassium N-aryl-sulfonyldithiocarbimates with Morita-Baylis-Hillman derivatives bearing phenyl and furyl groups. These are the first examples of allyldithiocarbimate anions and were isolated as tetraphenylphosphonium salts. The new compounds were characterized by HRMS, NMR and Infrared spectroscopy. Further, the structures of three allyldithiocarbimates were determined by single crystal X-ray diffraction. The compounds are isostructural and crystallize in the space group P21/c of the monoclinic system, and the allyldithiocarbimate anions present Z configuration. All the compounds were active against Botrytis cinerea. The best results were achieved with the tetraphenylphosphonium (Z)-3-(furan-2-yl)-2-(methoxycarbonyl)allyl-(4-chlorophenylsulfonyl)dithiocarbimate (IC50 38 μM).Item Syntheses, characterization and antifungal activity of heteroleptic nickel(II) complexes with N-alkylsulfonyldithiocarbimates and phosphines(Journal of Molecular Structure, 2016-06-15) Vidigal, Antonio E. C.; Rubinger, Mayura M. M.; Oliveira, Marcelo R. L.; Guilardi, Silvana; Souza, Rafael A. C.; Ellena, Javier; Zambolim, LaercioFour nickel(II) complexes of general formula [Ni(RSO2NCS2) (PPh3)2] where R = CH3 (2a), CH3CH2 (2b), CH3(CH2)3 (2c) and CH3(CH2)7 (2d) and PPh3 = triphenylphosphine; and two nickel(II) complexes of general formula [Ni(RSO2NCS2)dppe] where R = CH3(CH2)3 (3c) and CH3(CH2)7 (3d) and dppe = 1,2-bis(diphenylphosphine)ethane) were prepared. These new complexes were obtained by the reaction of nickel(II) chloride hexahydrate with potassium N-alkylsulfonyldithiocarbimates and the appropriate phosphine using ethanol/water as solvent. The IR, UV–Vis and ^1 H, ^13 C and ^31 P NMR spectra, elemental analysis of Ni and the HR-ESI-MS were consistent with the formation of square planar nickel(II) complexes with mixed ligands. The structures of the compounds 2b and 2c were determined by single crystal X-ray diffraction. The compounds are isostructural and crystallize in the space group P of the triclinic system. The activities of the complexes were investigated in vitro against Botrytis cinerea, Colletotrichum acutatum and Alternaria solani, fungi species that affect various commercially important plants. All the complexes were active.Item Syntheses, crystal structure and theoretical investigation of novel heteroleptic complexes of nickel(II) with N-R-sulfonyldithiocarbimate and phosphine ligands(Inorganica Chimica Acta, 2011-10-01) Oliveira, Marcelo Ribeiro Leite; Franca, Eduardo de Faria; Novais, Celice; Guilardi, Silvana; Machado Jr., Iterlandes; Ellena, Javier; Amim Jr., Jorge; Bellis, Vito Modesto de; Rubinger, Mayura Marques MagalhãesFive new complexes of general formula: [Ni(RSO2NCS2)(dppe)], where R = C6H5 (1), 4-ClC6H4 (2), 4-BrC6H4 (3), 4-IC6H4 (4) and dppe = 1,2-bis(diphenylphosphino)ethane and [Ni(4-IC6H4SO2NCS2)(PPh3)2] (5), where PPh3 = triphenylphosphine, were obtained in crystalline form by the reaction of the appropriate potassium N-R-sulfonyldithiocarbimate K2(RSO2NCS2) and dppe or PPh3 with nickel(II) chloride in ethanol/water. The elemental analyses and the IR, ^1H NMR, ^13C NMR and ^31P NMR spectra are consistent with the formation of the square planar nickel(II) complexes with mixed ligands. All complexes were also characterized by X-ray diffraction techniques and present a distorted cis-NiS2P2 square-planar configuration around the Ni atom. Quantum chemical calculations reproduced the crystallographic structures and are in accord with the spectroscopic data. Rare C–H···Ni intramolecular short contact interactions were observed in the complexes 1–5.Item 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.Item Synthesis, molecular properties prediction and cytotoxic screening of 3-(2-aryl-2-oxoethyl)isobenzofuran-1(3H)-ones(Elsevier Bioorganic & Medicinal Chemistry Letters, 2016-04-25) Maia, Angélica Faleiros da Silva; Siqueira, Raoni Pais; Oliveira, Fabrício Marques de; Ferreira, Joana Gasperazzo; Silva, Silma Francielle da; Caiuby, Clarice Alves Dale; Oliveira, Leandro Licursi de; Paula, Sérgio Oliveira de; Souza, Rafael Aparecido Carvalho; Guilardi, Silvana; Bressan, Gustavo Costa; Teixeira, Róbson RicardoIn the present investigation, a collection of nineteen 3-(2-aryl-2-oxoethyl)isobenzofuran-1(3H)-ones was synthesized and screened for their cytotoxic activity against a panel of three leukemia cancer cell lines. The compounds were prepared via ZrOCl2·8H2O catalyzed condensation reactions between phthalaldehydic acid and different acetophenones. The reactions were carried out free of solvent and the isobenzofuran-1(3H)-ones were obtained in good yields (80–92%). The identities of the synthesized compounds were confirmed upon IR and NMR (1H and 13C) spectroscopy as well as high resolution mass spectrometry analyses. Structures of compounds 1, 4 and 16 were also investigated by X-ray analysis. The synthesized compounds were submitted to in vitro bioassays against HL-60, K562 and NALM6 cancer cell lines using MTT cytotoxicity assay. After 48 h of treatment, twelve derivatives were able to reduce cell viability and presented IC50 values equal to or below 20 μmol L−1 against at least one of the evaluated lineages. The most active compound corresponded to 3-(3-methylphenyl-2-oxoethyl)isobenzofuran-1(3H)-one (18) (IC50 values obtained for HL-60, K562 and NALM6 were, respectively, 13.5 μmol L−1, 8.83 μmol L−1, and 5.24 μmol L−1). In addition, compound 18 was capable of triggering apoptosis on NALM6 cells. All isobenzofuranones herein evaluated did not present cytotoxicity on peripheral blood mononuclear cells (PBMC), suggesting selective cytotoxic effect on leukemic cells. A computational study allowed prediction of pharmacokinetics and drug-likeness properties of the synthesized compounds. DFT calculations were performed to obtain the energy values of HOMO, LUMO, and dipole moments of isobenzofuranones.Item Centrosymmetric resonance-assisted intermolecular hydrogen bonding chains in the enol form of -diketone: Crystal structure and theoretical study(Journal of Molecular Graphics and Modelling, 2016-06-09) Franca, Eduardo F.; Guilardi, Silvana; Paixão, Drielly A.; Teixeira, Róbson R.; Pereira, Wagner L.; Ellena, Javier A.Isobenzofuran-1(3H)-ones (phtalides) are heterocycles that present a benzene ring fused to a γ-lactone functionality. This structural motif is found in several natural and synthetic compounds that present relevant biological activities. In the present investigation, the 3-(2-hydroxy-4,4-dimethyl-6-oxocyclohexen-1-yl)isobenzofuran-1(3H)-one was characterized by single-crystal X-ray analysis. In the crystal structure, there are two molecules per asymmetric unit. One of them exhibits resonance assisted hydrogen bonds (RAHBs). Semi-empirical and DFT calculations were performed to obtain electronic structure and π-delocalization parameters, in order to better understand the energy stabilization of RAHBs in the crystal packing of the studied molecule. The structural parameters showed good agreement between theoretical and experimental data. The theoretical investigation revealed that the RAHBs stabilization energy is directly related to the electronic delocalization of the enol form fragment. In addition, RAHBs significantly affected the HOMO and charge distribution around the conjugated system.Item Synthesis and antifungal activity of halogenated aromatic bis-γ-lactones analogous to avenaciolide(Química Nova, 2011-11-08) Castelo-Branco, Pedro A.; Rubinger, Mayura M. M.; Alves, Leandro de C.; Liberto, Natalia A.; Nepel, Thayane C. M.; Catrinck, Mariana; Guilardi, Silvana; Silvério, Hudson A.; Zambolim, Laércio; Piló-Veloso, Dorila; F. Neto, Wilson P.Here we describe the total syntheses and characterization by elemental analyses, infrared and NMR spectroscopy of three new compounds analogous to avenaciolide, a bis-γ-lactone isolated from Aspergillus avenaceus that possesses antifungal activity, where the octyl group of the natural product was replaced by aromatic groups containing chlorine and fluorine atoms. The effects of the avenaciolide, the novel compounds and their synthetic precursors on mycelia development and conidia germination of Colletotrichum gloeosporioides and Fusarium solani were evaluated in vitro. The title compounds were almost as active as avenaciolide. The absolute structures of the chlorinated analogs were determined by X-ray diffraction analysis.