Search

Fundação de Apoio a Pesquisa e à Inovação Tecnológica do Estado de Sergipe - FAPITEC/SE Density Functional Theory (DFT) calculations and its time dependent approach (TDDFT) have been performed to investigate the ligand effect on the structural and optical properties of the Au13 and Au13 3+ clusters. In the first part of this work, it has been investigated through the analysis of the potential energy curves, the most favorable coordination site of the NH3, PH3, SCH3 and SeCH3 ligands on the Au13 cluster. The results show that the NH3 and PH3 ligands bind preferentially on top site, while for the other ligands the coordination to the (111) site is energetically more favorable. In addition, it was studied the ligand influence on the structural, electronic and optical properties of the Au13L, where L = NH3, N(CH3)3, PH3, P(CH3)3, SCH3, SCH2Ph, SCH(CH3)NH2, SCH(CH3)Cl, SPh, SPhCH3 , SPhCOOH and SeCH3. The analysis of the electronic stabilities reveals that the Au13SCH(CH3)Cl and Au13NH3 are the most stable among the other clusters of the thiolate or selenolate and of the phosphine or amine-ligated groups, respectively. The ligand effect on the optical absorption spectra of Au13L is relatively small, in which the main change is observed in the intensity of the highest energy peak. In the second part of this work, it has been developed a systematic structural analysis of Au13L8 3+, where L = SCH3, SeCH3, SCH2OCH3 e S(CH3)2NH2, to exam the influence of different ligands. Binding energy calculations indicate that the gold core is more stabilized by the ligand in the following sequence S(CH3)2NH2 > SCH2OCH3 > SeCH3 > SCH3. Natural Bond Analysis (NBO) shows that the strongest electron donation occurs from a lone pair orbital on the sulfur and selenium atoms to the antibonding acceptor o* (Au−S) and o* (Au−Se), respectively. TDDFT calculations have been performed to simulate the optical absorption spectra of Au13L8 3+ in gas phase and under the effect of solvents with different polarities. The absorption spectrum of [Au13(S(CH2)2NH2)8]3+ shows a spectral profile that differs considerably from the others in gas phase and which is strongly affected by solvent. Cálculos da teoria do funcional de densidade (do inglês, Density Functional Theory – DFT) e sua abordagem dependente do tempo (TDDFT) foram realizados para investigar a influência de diferentes ligantes nas propriedades estruturais e ópticas dos clusters de ouro Au13 e Au13 3+. Inicialmente foi investigado, por meio das curvas de energia potencial, o sítio de coordenação mais favorável de diferentes ligantes (NH3, PH3, SCH3 e SeCH3) no cluster de Au13. Os resultados mostram que o ligante aminado e o fosfinado se coordenam preferencialmente ao sítio on top, enquanto que, para os demais ligantes, a coordenação ao sítio da face (111) se mostra energeticamente mais favorável. Em seguida, foi estudada a influência dos ligantes sobre as propriedades estruturais, eletrônicas e ópticas do cluster de Au13L, sendo L = NH3, N(CH3)3, PH3, P(CH3)3, SCH3, SCH2Ph, SCH(CH3)NH2, SCH(CH3)Cl, SPh, SPhCH3, SPhCOOH e SeCH3. A análise dos resultados da estabilidade eletrônica revelou que os clusters de Au13SCH(CH3)Cl e Au13NH3 são os mais estáveis dentre àqueles que pertencem ao grupo dos tiolados ou selenolado e ao grupo dos aminados e fosfinados, respectivamente. Posteriormente, foi avaliada a influência dos ligantes sobre os espectros de absorção do Au13L, onde o principal efeito está na intensidade da banda de mais alta energia. Na segunda parte deste trabalho foi realizada uma análise estrutural do Au13L8 3+, onde L = SCH3, SeCH3, SCH2OCH3 e S(CH3)2NH2. Cálculos de energia de ligação indicam que o Au13 é mais estabilizado pelo ligante de acordo com a sequência: S(CH3)2NH2 > SCH2OCH3 > SeCH3 > SCH3. A análise dos orbitais naturais de ligação (do inglês, Natural Bond Orbitals ‒NBO) mostra que a doação eletrônica mais forte ocorre dos orbitais não ligantes sobre os átomos de enxofre ou selênio para os orbitais antiligantes o* (Au-S) e o* (Au-Se), respectivamente. Além disso, ela permitiu entender a origem da maior estabilidade do [Au13(S(CH2)2NH2)8]3+. Os espectros ópticos de absorção do Au13L8 3+ foram calculados em fase gasosa e sob o efeito de solventes. O espectro de absorção do [Au13(S(CH2)2NH2)8]3+ mostra um perfil espectral que difere dos demais clusters em fase gasosa e o mesmo é fortemente afetado pelo efeito do solvente. São Cristóvão, SE

Aplicações biológicas de nanopartículas inorgânicas demandam o entendimento das interações entre as nanopartículas e as proteínas. Nessa tese foram realizados estudos de interação entre a proteína BSA e nanopartículas de maghemita funcionalizadas com diferentes ligantes aniônicos (íons citrato, íons tripolifosfato e bicamada de íons laurato), por três técnicas analíticas: titulação de calorimetria isotérmica (ITC), isoterma de adsorção por medidas de diâmetro hidrodinâmico, empregando espalhamento de luz dinâmico (DLS) e espectroscopia de fluorescência. Os valores das constantes de interação (Ka) obtidos pelos estudos de adsorção da BSA sobre as nanopartículas por medidas de DLS foram semelhantes aos obtidos por ITC, para os três sistemas. Por outro lado, os estudos por ITC, não permitiram a determinação dos valores das estequiometrias de reação (Nmax). Os resultados obtidos pela técnica de fluorescência são altamente discrepantes em relação aos resultados obtidos pelas outras duas técnicas. A avaliação do papel do agente funcionalizante sobre a interação entre as nanopartículas e a BSA mostrou que há diferenças no perfil das interações nos três sistemas estudados. O valor da constante de associação para o sistema BSA-NP-Citrato foi da ordem de 106 mol.L-1, enquanto que para os demais sistemas foi de 104 mol.L-1. Os parâmetros termodinâmicos obtidos para o sistema BSA-NP-Citrato (ΔH = 5x103 cal.mol-1; ΔS+ +45 cal.mol-1; ΔG= -8410 cal.mol-1) sugerem que o processo de adsorção foi predominantemente de natureza eletrostática. Por outro lado, os parâmetros termodinâmicos obtidos para os sistemas, BSA-NP-Laurato (ΔH=-1,38x105 cal.mol-1; ΔS= -441cal.mol-1; ΔG= -6582 cal.mol-1) e BSA-NP-Tripolifosfato (ΔH = - 1,86x104 cal.mol-1; ΔS= -41 cal.mol-1; ΔG= -6352 cal.mol-1) sugerem que o processo de adsorção nesses sistemas tenha ocorrido predominantemente por pontes de hidrogênio. A atividade de esterase da albumina foi reduzida pela interação com as nanopartículas, e foi dependente da concentração das mesmas. A redução na atividade da esterase ocorreu em maior extensão para o sistema BSA-NP-Laurato. Nesse trabalho, a técnica de espalhamento de luz dinâmico (DLS) foi empregada pela primeira vez para o estudo de adsorção de BSA sobre nanopartículas de maghemita funcionalizadas, e se mostrou adequada. Além disso, nas condições experimentais utilizadas, foi a única técnica que forneceu valores da estequiometria de reação (Nmax) semelhante aos valores estimados. Biological applications of nanoparticles require understanding the interaction between proteins and nanoparticles. In this thesis were performed studies of interaction between the protein BSA and maghemite nanoparticles functionalized with different anionic ligands (citrate ions, tripolyphosphate ions and bilayer laurate ions ), by three analytical techniques: isothermal titration calorimetry (ITC), adsorption isotherm by hydrodynamic diameter measurements using dynamic light scattering (DLS) and fluorescence spectroscopy. The values of the interaction constants (Ka) of BSA association on nanoparticles surface by DLS measurements were similar to those obtained by ITC, for the three systems. On the other hand, the study by ITC did not allows determining of the stoichiometry values (Nmax) of the association processes. The results obtained by the fluorescence technique are highly discrepant of the results obtained by the other two techniques. The evaluation of the functionalizing agent effect on the interaction between magnetite nanoparticles and BSA showed that there are differences in the Ka values, and in the energetic profiles of the interactions for the three systems studied. The Ka value for the interaction between BSA and citrate functionalized nanoparticles was in the order of 106 M-1, whereas for the other systems the values of Ka were 104 M-1. The energetic profile of the interactions, was endothermic in the system BSA-NP-Citrate, and exothermic for BSA-NP-Laurato and for BSA-NP-Tripolyphosphate. From the analysis of the thermodynamic parameters, it was possible to suggest that the interaction in the BSA-NP-citrate system was predominantly electrostatic, whereas the interaction in the other systems predominantly involved hydrogen bonds. The albumin estearase activity was reduced by the interaction with the nanoparticles, and was dependent upon the nanoparticles concentration. The reduction in stearase activity was higher for the -BSA-NP-Laurate system. In this work, the dynamic light scattering technique (DLS) was used, for the first time, to study of adsorption of BSA on functionalized maghemite nanoparticles. In addition, under the experimental conditions used, DLS was the only technique that provided (Nmax) values similar to those estimated. Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG

O Ferro é um micronutriente essencial para o fitoplâncton, presente em pequenas concentrações no meio marinho, apesar que, em zonas costeiras como a Plataforma Continental Sul Brasileira possa ser encontrado em concentrações mais elevadas. Sua biodisponibilidade e solubilidade na água do mar dependem principalmente da sua complexação por moléculas orgânicas. Deste modo, muitos estudos têm sido desenvolvidos e relacionados à especiação orgânica deste elemento. Para tanto, tem se buscado o aprimoramento e a implementação de métodos mais eficientes para a especiação orgânica desse elemento. Conhecendo a escassez de trabalhos relacionados à especiação orgânica de ferro na costa brasileira, principalmente na região sul, onde existe altas concentrações deste elemento. Este estudo tem como objetivo avaliar a especiação orgânica do ferro dissolvido na Plataforma Continental do Sul do Brasil (PCSB). Para isso, esse estudo foi divido em dois capítulos: o primeiro, descreve a adaptação do método voltamétrico para a especiação orgânica de ferro (CLE-AdCSV) usando salicilaldoxima (SA) e a segunda parte deste trabalho foi feita a aplicação do método nas amostras oriundas da PCSB. No primeiro capítulo foram adaptados dois métodos: um para determinação do ferro e outro para especiação orgânica, além disso foram feitos estudos de estabilidade e intensidade do sinal analítico. Para garantir a repetibilidade, foi implementado um purga de ar filtrado acoplado a um sistema de vácuo na célula voltamétrica, a temperatura, o pH e o condicionamento da mesma também foram otimizados.Foram avaliados o potencial de deposição e a concentração de SA, tendo sido observado a melhor concentração 25μM de SA e 0 V como o melhor potencial de deposição. Dessa forma, para a análise de especiação orgânica de ferro algumas adaptações do método (CLE-AdCSV) foram feitas, dentre elas, a velocidade de varredura e o tempo de equilíbrio entre os ligantes naturais e a SA. Desse modo, adquiriu-se dois métodos nesse capítulo, sendo ambos validados usando um material certificado, obtendo-se limites de quantificação (LQ) para a determinação de Fe total e especiação de 1,06 nM e 1,43 nM, respectivamente. A partir da confiabilidade de ambos métodos foi possível investigar a biogeoquímica do ferro, em relação a especiações orgânica, na região escolhida como local de coleta de amostras. Assim, no segundo capítulo é descrito as regiões amostrais, uma localizada em frente ao Farol do Albardão e outra na região do Cabo Santa Marta, entre 32°S e 28,5°S, respectivamente. A bordo do Navio Oceanográfico Atlântico Sul foram coletadas amostras de água durante o verão e inverno de 2015 no transecto do Albardão e durante o inverno de 2015 em Santa Marta. Em ambas as localidades, as amostras de água foram com garrafas Go-Flo (coletadas superfície e fundo) no verão e um sistema do tipo “fish” (somente superfície) no inverno. Foram analisados nutrientes inorgânicos dissolvidos (nitrato, silicato e fosfato) e perfis verticais de temperatura e salinidade, obtidos utilizando um CTD. As maiores concentrações de ferro dissolvido (FeD) foram verificadas na pluma do Rio da Prata em ambos transectos. As concentrações de FeD e todos os nutrientes analisados foram menores nas massas de água mais oligotróficas, tais como, Água Tropical (AT) e Água Subtropical de Plataforma, com exceção do nitrato em Santa Marta. Essa anomalia também foi observada na presença de ligantes orgânicos na mesma região, associada à produção biológica. Como esperado, foram encontradas baixas concentrações de ferro livre, Fe+3, não chegando a 1% do FeD na amostra. Além disso, foram verificadas altas capacidades de complexação (L), e excesso de ligantes (eL) em todos os transectos, superando os valores de ferro dissolvido encontrados. Os valores da constante de estabilidade apresentado em todos os períodos amostrados variaram entre 12,32 – 8,97 o que indica até três classes de ligantes. Os resultados destes transectos foram comparados com outras localidades do mundo, mostrando semelhança com regiões ricas em ácidos húmicos, regiões de descarga fluviais e altas produções biológicas. As altas concentrações de FeD sobre a plataforma podem influenciar a formação de ligantes, gerando alta capacidade de complexação ao longo de todos os transectos, mantendo o ferro solúvel na coluna d’água e, consequentemente, tornando-o biodisponível. Assim acredita-se que a ação de correntes oceânicas pode atuar na distribuição deste elemento, em sua forma solúvel, para o oceano adjacente o que promoveria a fertilização de locais mais afastados da costa. Iron is an micronutrient for phytoplankton, its concentration is small in the marine environment, although, in coastal areas like the Southern Brazilian Continental Shelf it can be found in higher concentrations. Its bioavailability and solubility in seawater depends on mainly your complexation by organic molecules. In this way, many studies have been developed and related to organic speciation of this element. To this end, has sought the improvement and the implementation of more efficient methods for organic speciation of this element. Knowing the shortage of organic speciation-related jobs in the Brazilian coast, mainly in the South, where there are high concentrations of the element. This study aims to evaluate the organic speciation of dissolved iron in the Continental Shelf of southern Brazil (PCSB). To this end, this study was divided into two chapters: the first describes the adaptation of two voltammetrics methods CLE-AdCSV using salicylaldoxime (SA) and the second presents organic speciation of iron in PCSB. In the first chapter were adapted two methods: one for determination of iron and another for organic speciation. In this chapter, the results guaranteed two factors signal stability and signal strength. For repeatability: was implemented one plus purge system of filtered air and a vacuum system in cell, temperature, pH and conditioning of this were also adaptations necessary for the stability of the signal. For a better intensity were tests of potential deposition and concentration of SA, having been observed better concentrating 25µM de SA and 0 V as the best potential for deposition. That way in the analysis of organic speciation adaptations were also needed, including the scanning speed and time of balance between the natural ligands and the SA. Thereby acquired two methods in this chapter, both being validated using a material certificate, obtaining low limits of quantification (LQ) .1.06 nM for the determination of Fe and 1.43 nM for speciation. The best method was used for determining LQ. From the reliability of both methods it was possible to investigate the Biogeochemistry of iron in relation to organic speciation in the region chosen as site of specimen collection. Thus, in chapter two described that there were two sampling campaigns in two regions, one located in front of the Albardão and another lighthouse in the Cape Santa Marta, between 32° S and 28.5° S. On board the ship South Atlantic Oceanographic water samples were collected during the summer and winter of 2015 in transect of the Albardão and during the winter of 2015 in Santa Marta. In both localities, water samples were sampled with Go-Flo bottles (collected surface and bottom) in the summer and a system of type "fish" (surface) in the winter. Under such samples were analyzed the dissolved inorganic nutrients (nitrate, phosphate and silicate) and vertical profiles of temperature and salinity, obtained using a CTD. The largest concentrations of dissolved iron (dFe) were observed in the plume of the Río de la Plata in both transects. The dFe and all the nutrients analyzed were lower in more oligotrophic water masses, Tropical Water (WT) and Subtropical Shelf Water (SSW), except for nitrate in Santa Marta. This anomaly was also observed in the presence of organic ligands in the same region, associated with organic production. The largest concentrations of dissolved iron (EDF) were observed in the plume of the La Plat River in both transects. As expected, were found low concentrations of free iron, Fe+ 3, not reaching 1% of the dFe. In addition, verified high complexation capacities (L), and excess ligand (eL) on all transects, exceeding the values of dissolved iron found. The stability constant values, presented in all periods sampled ranged from 12.32-8.97 indicating up to three classes of ligands. The results of these transects were compared with other places in the world showing similarity to regions rich in humic acids, river discharge and high regions organic production. The high concentrations of dFe on the shelf can influence the formation of ligand, generating high complexation capacity along all transects, keeping the iron soluble in the water column and, consequently the making it bioavailable. Thus, it is believed that the action of ocean currents can act in the distribution of this element in your form soluble, adjacent to the ocean which would promote fertilization of these sites further away from the coast.

This paper reports the development of a novel methodology for the catalytic synthesis of aromatic alpha-amino acids, which involves the addition of aryl-organoboron reagents to alpha,alpha-ditosylamino esters derived from ethyl glyoxylate, using transition metal catalysts, like Rh and Pd. A library of alpha-amino esters (12 with Pd and 8 with Rh), was synthesized with moderate to excellent yields. A highest enantioselectivity of 30% ee was obtained using Hayashi's ligand. This method was applied to the synthesis of phenylglycine.

Two simple hemilabile P,O-coordinating phosphinoamidoester ligands 6a and 6b were synthesized and studied in the Pd(0)-catalyzed asymmetric allylic alkylation of rac-1,3-diphenylpropenyl acetate affording a highest ee of 83% ee with 6a. To gain an insight into the actual mechanism of this catalytic reactions, which had previously been investigated with a first generation family of P,O-coordinating phosphinoamido-alcohol ligands—4a and 4b—a semiempirical computational study was carried out with the Pd-allyl complexes formed from both 4a and 6a including Hitchcock's phosphinoamido-alcohol ligand 5 (R1 = H, R2 = Ph). The results of this study substantiate a working model that has previously been proposed for this reaction using hemilabile P,O-coordinating phosphinoamido-type ligands. Chirality 2011 © 2011 Wiley-Liss, Inc

[RE(czb)3(H2O)2] complexes (where RE = Eu3+, Tb3+, Gd3+; and czb = 4-(9H-carbazol-9-yl)benzoato) have been synthesized and characterized. The Gd3+ complex was used to determine the triplet state energy of the czb ligand. Photoluminescence measurements of the complexes have been carried out under UV excitation. The Tb3+ complex exhibited a strong green luminescence indicating an efficient antenna effect, whereas the Eu3+ complex showed low red luminescence and the Gd3+ complex a blue-green luminescence from the ligand. The luminescence lifetimes and quantum yields have also been measured for the evaluation of the spectroscopic behavior of the complexes.

This study describes the use of three (-)-alpha-pinene derivatives, one diol-1,2 [(-)-(1R, 2R, 3S, 5R)-2,6,6-trimethylbicyclo[3.1.1]heptane-2,3-diol 4] and two piridine-hydroxy derivatives [(+)-(1R,2S,3R,5S)-2,6,6-trimethyl-3-(2-pyridinylmethyl)bicyclo[3.1.1]heptan-3-ol 7 and (-)-(1R,2S,3R,5S)-2,6,6-trimethyl-3-[2-(2-pyridinyl) ethyl]bicyclo[3.1.1]heptan-3-ol 8]; one diol-1,3 [(-)-(1S,2R,5S)-2-(1-hydroxy-1-methylethyl)-5-methylcyclohexanol 5] derived from (+)-isopulegol 2 and one diol-1,3 [(+)-(1R,2R,5R)-2-(1-hydroxy-1-methylethyl)-5-methylcyclohexanol 6] derived from (+)-neo-isopulegol 3, as ligands in the asymmetric Reformatsky reaction. The best enantiomeric excess of beta-hydroxy ester obtained in the Reformatsky asymmetric reaction was 18% using ligand 6, and the chemical yield of the reactions was 65% on average.

The [RuCl(bipy)(dppb)(4-pic)]PF6 complex was prepared and fully characterized. The X-ray crystal structure of this complex was determined in order to make an unambiguous distinction between the two possible positions of the 4-methylpyridine ligand (4-pic) in the compound: trans to phosphorus atom or trans to nitrogen atom. The [RuCl(bipy)(dppb)(4-pic)]PF6 complex exhibits an unusual temperature-dependent accidental degeneracy of the 31P chemical shifts in its solution NMR spectrum.

Atropisomerism is a special kind of stereoisomeric relationship that arises from the freezing of a certain conformation of an organic molecule, associated with a high rotational barrier about a single covalent bond. Atropisomerism has been originally described in orto-functionalyzed biphenyl derivatives, but a lot of other organic functionalities can present this structural phenomenon, characterized by the presence of chiral properties in compounds that don't present classical stereogenic centers. Atropisomeric compounds, intermediates and catalysts have well-know importance in organic synthesis, but the influence of the axial chirality in substances able to modulate biological systems is still not very exploited in drug design and development. In this context, the present account describes the importance of this structural property in the medicinal chemistry of different classes of bioactive compounds or therapeutic agents, emphasizing how atropisomerism could affect the molecular recognition of a ligand or a prototype by the target bioreceptor.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T18:48:36Z No. of bitstreams: 1 S0100-40422006000400024.pdf: 123060 bytes, checksum: 529dfef3a32286eefd3e2611ba02cd6f (MD5) Made available in DSpace on 2013-08-22T18:48:36Z (GMT). No. of bitstreams: 1 S0100-40422006000400024.pdf: 123060 bytes, checksum: 529dfef3a32286eefd3e2611ba02cd6f (MD5) Previous issue date: 2006-07-01 Made available in DSpace on 2013-09-30T19:38:35Z (GMT). No. of bitstreams: 2 S0100-40422006000400024.pdf: 123060 bytes, checksum: 529dfef3a32286eefd3e2611ba02cd6f (MD5) S0100-40422006000400024.pdf.txt: 27450 bytes, checksum: 8becb3d10c68446d0d24f100d1cd27f1 (MD5) Previous issue date: 2006-07-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T14:19:56Z No. of bitstreams: 2 S0100-40422006000400024.pdf: 123060 bytes, checksum: 529dfef3a32286eefd3e2611ba02cd6f (MD5) S0100-40422006000400024.pdf.txt: 27450 bytes, checksum: 8becb3d10c68446d0d24f100d1cd27f1 (MD5) Made available in DSpace on 2014-05-20T14:19:56Z (GMT). No. of bitstreams: 2 S0100-40422006000400024.pdf: 123060 bytes, checksum: 529dfef3a32286eefd3e2611ba02cd6f (MD5) S0100-40422006000400024.pdf.txt: 27450 bytes, checksum: 8becb3d10c68446d0d24f100d1cd27f1 (MD5) Previous issue date: 2006-07-01 This article deals with synthesis and reactivity of complexes with triphenylstibine (SbPh3) as the ligand. A comparative study of analogous complexes of triphenylphosphine (PPh3) and triphenylarsine (AsPh3) with platinum in the oxidation states zero, two and four is included. The bibliographic revision includes publications since 1936, when the first Pt(II) complex with triphenylstibine was described. Faculdade de Minas Universidade Vale do Rio Verde Universidade Federal de Viçosa (UFV) Departamento de Química Universidade Estadual Paulista Julio de Mesquita Filho Universidade Estadual Paulista Julio de Mesquita Filho

A determinação de estruturas tridimensionais de quelatos com metais pesados e de alguns potencialmente úteis agentes quelantes, é uma ferramenta muito importante no estudo de complexos que poderão agir como antídotos na intoxicação por ingestão de metais pesados. Um conhecimento detalhado destes complexos é exigido para auxiliar na modelagem de estruturas moleculares e na determinação de procedimentos que sejam mais efetivos na neutralização dos processos, desenvolvidos por indivíduos com intoxicação crônica por metais pesados. Aqui serão reportados os resultados de um estudo sistemático de complexos [TlMe2L], onde L = 2-mercapto-3-piridina ácido carboxílico (I), 6-mercapto-3-piridinametoxicarboxilato (II), 2-mercapto-3-piridina-metoxicarboxilato (III), 6-mercapto-3-piridina-etoxicarboxilato (IV) e 2-mercapto-3-piridina-etoxicarboxilato (V). O estudo dos arranjos supramoleculares destes complexos mostra que, apesar das diferenças na simetria dos grupos espaciais e os substituintes nos ligantes, o empacotamento no cristal são similares. Os complexos formam polimeros infinitos em uma, duas e três dimensões, baseadas em interações TI - S, T1 - N e T1 - O e ligações de hidrogênio. Existem várias formas de correções dos dados de difração de raios X em monocristais. Durante o processamento das intensidades coletadas realizam-se várias correções, tais como de Lorentz, polarização, absorção e eventualmente correção por deterioração da amostra. A correção por absorção é fortemente recomendada para cristais que possuem fortes absorvedores em sua forma estrutural. Foram estudados os efeitos da absorção dos raios X em amostras cristalinas e uma comparação dos resultados obtidos ao aplicar os diferentes métodos de correções por absorção disponíveis. Constatou-se que após serem realizados diferentes formas de correção por absorção, houve diferenças significativas nas figuras de mérito, picos e vales de densidade de carga residual e parâmetros de deslocamentos anisotrópicos. Já nos ângulos e distâncias de ligações não foram observados mudanças significativas. The determination of the three-dimensional structures of heavy-metal chelates and of some potentially useful chelating agents is a very important to01 in the study of complexes that may act as antidotes against poisoning by ingestion of heavy metals. A detailed knowledge of these complexes is expected to assist in the design of molecular structures and procedures that are more effective in counteracting the life threatening processes inevitably developed by individuals with chronic heavy-metal intoxication. Within this framework a series of dimethylthallium(III) complexes were studied. Here we present complexes of the type [TlMe2L], where L=2-mercapto-3- pyridine carboxylic acid(I), 6-mercapto-3-pyridine-methoxycarboxylate(II), 2-mercapto-3-pyridine-methoxycarboxylate(III), 6-mercapto-3-pyridineethoxycarboxylate(IV) and 2-mercapto-3-pyridine-ethoxycarboxylate(V). The study of the supramolecular arrangement of these complexes shows that, in spite of the differences in space group symmetry and substituents in the ligand, the crystals packing are remarkably similar. The complexes form infinite polymers in one, two and three dimensions, based upon TI-S, T1-0 e T1-N covalent bonds and intermolecular secondary interactions. The complexes also present strong hydrogen bond intermolecular interactions. There are many forms of corrections to the data collected in a single crystal X-ray diffration experiment. During the data reduction many corrections take place, such as: Lorentz, polarization, absorption and eventualy corrections for the deterioration of the sample. The absorption correction is strongly recommended for crystals with strong absorbers in its structural form. The effect of the absorption of the X rays has been studied in crystalline samples, as well as a comparison between the result obtained from the different available methods of absorption corrections. This work that showed different forms of absorption correction, made significant differences in the merit figures, peak and hole of residual charge density, as well as the anisotropic displacements parameters. Bonds distances and angles, on the other hand, did not change significantly.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T18:49:09Z No. of bitstreams: 0 Made available in DSpace on 2013-08-22T18:49:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2001-01-01 Made available in DSpace on 2013-09-30T19:09:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2001-01-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T14:19:47Z No. of bitstreams: 0 Made available in DSpace on 2014-05-20T14:19:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2001-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Este trabalho descreve uma revisão a respeito do uso do ligante dietilditiofosfato de amônio em química analítica e suas potencialidades no campo da análise química espectrofotométrica (UV/VIS) e espectrométrica (AAS, ICP-AES, ICP-MS) em diferentes matrizes e meios. A discriminação de espécies químicas por meio de complexações seletivas de elementos químicos com dietilditiofosfato e a hifenação de técnicas espectroscópicas a etapas de separação como extração em fase sólida, extração líquido-líquido, extração por cloud point, são outros assuntos abordados neste trabalho. This paper describes a critical review on the use of ammonium diethyl dithiophosphate in analytical chemistry and the potentialities of this ligand in spectrophotometric (UV/VIS) and spectrometric (AAS, ICP-AES, ICP-MS) analyses in different matrices and medium. The speciation of chemical species by coupling complexation reactions between chemical elements and ammonium diethyl dithiophosphate as well as the hyphenation of spectroscopic techniques to separation steps such as solid phase extraction, solvent extraction, cloud point extraction, are also commented in this paper. Universidade Estadual Paulista Instituto de Química de Araraquara Departamento de Química Analítica Universidade Estadual Paulista Instituto de Química de Araraquara Departamento de Química Analítica

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T18:48:25Z No. of bitstreams: 1 S0100-40421999000300008.pdf: 94896 bytes, checksum: 14507cd942cab367d6775dcab9b4aef2 (MD5) Made available in DSpace on 2013-08-22T18:48:25Z (GMT). No. of bitstreams: 1 S0100-40421999000300008.pdf: 94896 bytes, checksum: 14507cd942cab367d6775dcab9b4aef2 (MD5) Previous issue date: 1999-06-01 Made available in DSpace on 2013-09-30T19:38:15Z (GMT). No. of bitstreams: 2 S0100-40421999000300008.pdf: 94896 bytes, checksum: 14507cd942cab367d6775dcab9b4aef2 (MD5) S0100-40421999000300008.pdf.txt: 36117 bytes, checksum: 3f9896f118d41c8dc26cbce3efa6d3a1 (MD5) Previous issue date: 1999-06-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T14:19:59Z No. of bitstreams: 2 S0100-40421999000300008.pdf: 94896 bytes, checksum: 14507cd942cab367d6775dcab9b4aef2 (MD5) S0100-40421999000300008.pdf.txt: 36117 bytes, checksum: 3f9896f118d41c8dc26cbce3efa6d3a1 (MD5) Made available in DSpace on 2014-05-20T14:19:59Z (GMT). No. of bitstreams: 2 S0100-40421999000300008.pdf: 94896 bytes, checksum: 14507cd942cab367d6775dcab9b4aef2 (MD5) S0100-40421999000300008.pdf.txt: 36117 bytes, checksum: 3f9896f118d41c8dc26cbce3efa6d3a1 (MD5) Previous issue date: 1999-06-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Some cyclopalladated compounds containing the azido group ligand and the (C-N) ring of N,N-dimethylbenzylamine have been prepared by bridge opening reactions of dimmer azide complex precursor with some diphosphines in different stoichiometric quantities. The neutral or ionic, mono or binuclear complexes synthesized were characterized by elemental analyses, I. R. spectroscopy and NMR techniques. The series of complexes was screened for cytotoxicity against a panel three human tumour cells lines(C6,Hep-2,HeLa). All complexes were found to be cytotoxic (IC50) at µM concentrations while one complex having the coordination bond N-Pd ruptured also displayed some differential cytotoxicity. Universidade de Mogi das Cruzes Universidade Estadual Paulista Universidade Estadual Paulista

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2014-02-26T17:08:37Z No. of bitstreams: 1 WOSA1997XG70900008.pdf: 328924 bytes, checksum: 34691c4b84e5b3d1ce6f002a06272e09 (MD5) Made available in DSpace on 2014-02-26T17:08:37Z (GMT). No. of bitstreams: 1 WOSA1997XG70900008.pdf: 328924 bytes, checksum: 34691c4b84e5b3d1ce6f002a06272e09 (MD5) Previous issue date: 1997-05-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T15:26:38Z No. of bitstreams: 1 WOSA1997XG70900008.pdf: 328924 bytes, checksum: 34691c4b84e5b3d1ce6f002a06272e09 (MD5) Made available in DSpace on 2014-05-20T15:26:38Z (GMT). No. of bitstreams: 1 WOSA1997XG70900008.pdf: 328924 bytes, checksum: 34691c4b84e5b3d1ce6f002a06272e09 (MD5) Previous issue date: 1997-05-01 A general overview on the photochemical behaviour of [Ru(NH3)(5)L](2+) complexes (where L is a pi ligand) is presented. The proposed mechanisms and techniques employed for the study of these reactions are discussed. Emphasis is made on the mechanisms that allow the identification of the reactive excited state of the [Ru(NH3)(5)py](2+) complex. UNIV ESTADUAL PAULISTA JULIO MESQUITA,INST QUIM ARARAQUARA,ARARAQUARA,SP,BRAZIL UNIV SAO PAULO,FAC FILOSOFIA CIENCIAS & LETRAS RIBEIRAO PRET,BR-14040901 RIBEIRAO PRET,SP,BRAZIL UNIV SAO PAULO,INST QUIM SAO CARLOS,BR-13560970 SAO CARLOS,SP,BRAZIL UNIV ESTADUAL PAULISTA JULIO MESQUITA,INST QUIM ARARAQUARA,ARARAQUARA,SP,BRAZIL