This thesis contains an introduction to the surface chemistry of minerals in aqueous environment, and a summary of five manuscripts concerning adsorption reactions at the surfaces of nano-sized gibbsite (α-Al(OH)3), amorphous silica and kaolinite. Nano-sized gibbsite was synthesized and thoroughly characterized using X-ray diffraction, high-resolution transmission electron microscopy, atomic force microscopy and Fourier transform infrared spectroscopy. The adsorption of protons and the development of charge at the surfaces were studied using high precision potentiometry and zeta potential measurements. The results showed that singly coordinated surface sites at the particle edges protonate/deprotonate, while ion pairs with the medium ions are formed at doubly coordinated surface sites at the basal planes. This ion pair formation is a slow reaction, requiring long equilibrium times. The adsorption of o-phthalate, maleate, fumarate, malonate and oxalate onto gibbsite surfaces was studied using Fourier transform infrared spectroscopy, zeta potential measurements, adsorption measurements and theoretical frequency calculations. All ligands were found to form outer-sphere complexes at the basal planes. Significant amounts of inner-sphere complexes at the particle edges were found for malonate and oxalate only. The observed adsorption was described using surface complexation models. The proton reactions at the surface of amorphous silica were described using a two-site model. XPS indicated that Na+ is accumulated in the vicinity of the surface. Proton reactions at kaolinite surfaces were explained using a nonelectrostatic model, assuming that only the aluminol and silanol sites at the particle edges are reactive. Extensive modeling provided support for this assumption.

2-Aminopyrrole-3-carboxylate derivatives are important starting materials for biologically active compounds like pyrrolotriazole, pyrrolotriazine so their synthese has great importance in the synthetic organic chemistry. There are only two methods for the synthesis of 2-aminopyrrole-3-carboxylates in the literature. Therefore, there is a great need for the design and development of a new method for the synthesis of 2-aminopyrrole-3-carboxylates. In this work, 2-aminopyrrole-3-carboxylate derivatives were synthesized starting from cyano acetic acid ethyl ester with a new method. In the first step, cyanoacetic acid ethyl ester was alkylated with bromo acetone in the presence of NaH. Then, obtained gamma-ketoester was reacted with primary amines in the presence of catalytic amount of zincpechlorate (Zn(ClO4)2). As a result, 2-aminopyrrole-3-carboxylate derivatives were obtained. Cyanoacetic acid ethyl ester was also alkylated with various bromo acetophenone derivatives in the presence of DBU (1,8-Diazabicycloundec-7-ene). As a result of these reactions, different gamma-ketoesters were obtained. The reaction of these gamma-ketoesters with primary amines in the presence of catalytic amount of Zn(ClO4)2 concluded with 2-aminopyrrole-3-carboxylate derivatives.

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No. of bitstreams: 1 lippyfariamarques.pdf: 5076100 bytes, checksum: 2953e513680692299734c5fd00a57c88 (MD5) Previous issue date: 2010-03-05 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Este trabalho consistiu na síntese e caracterização de complexos de metais de transição, especialmente os íons metálicos da primeira série de transição, Cu2+, Co2+ e Zn2+, contendo o ânion dicarboxilato 2,6-piridinodicarboxilato bem como os ligantes nitrogenados rígido e flexível: 4,4’-bipiridina (BIPY) e 1,3-bis(4-piridil)propano (BPP). Todos os compostos sintetizados foram caracterizados por análise elementar (CHN), análise termogravimétrica (TG), espectroscopia vibracional na região do infravermelho (IV) e difração de raios X de monocristal. O capítulo 1 abrange uma breve introdução sobre Polímeros de Coordenação. Adicionalmente, incluiu-se uma apresentação sobre Química Supramolecular seguido de uma apresentação sobre o ligante carboxilato e os ligantes nitrogenados utilizados neste trabalho, destacando a intensa pesquisa na área. No capítulo 2 descreve-se a síntese do sal de sódio derivado do ácido dicarboxílico, bem como dos seis complexos contendo o ligante nitrogenado 1,3-bis(4-piridil)propano e o ligante nitrogenado BIPY. Estes complexos foram formulados como [Cu(2,6-PDC)(2,6-PDCH2)].3H2O (1), [Cu2 (μ-BPP) (2,6-PDC)2(H2O)2]. 2H2O (2), {[Co(H2O)4 (BPP)] [Co(2,6-PDC)2]. H2O}n (3) e (H2BPP) [Zn(2,6-PDC)2].4H2O (4), [ Co2 (μ-BIPY) (2,6-PDC)2(H2O)4]. 2H2O (5) e [Cu2(μ-O2CCH2C4H3S)4(Bipy)]n (6). O capítulo 3 relaciona-se com a caracterização dos complexos contendo o ligante nitrogenado 1,3-bis(4-piridil)propano. Os complexos (2) e (3) tiveram suas estruturas determinadas por difração de raios X de monocristal. O complexo (2) é homobimetálico com dois centros de Cu(II) em geometria pirâmide de base quadrada distorcida conectados através do ligante BPP em ponte. Por outro lado, o composto (3) apresenta uma porção complexa aniônica formada por um centro de Co(II) e dois ânions piridinodicarboxilatos e uma cadeia polimérica catiônica, constituída por íons Co(II) e ligantes BPP em ponte. Em ambos os casos um sistema supramolecular 3-D é gerado através de ligações de hidrogênio. Os dados analíticos e espectroscópicos para o composto (4) sugerem a formação de um complexo formado por duas porções. A porção aniônica é formada por dois ligantes 2,6-piridinodicarboxilatos coordenados de forma tridentada através da coordenação (O-N-O) ao centro de Zn(II) e estabilizando a carga um ligante nitrogenado BPP duplamente protonado. Esse tipo de estrutura é bem suportado por vários exemplos da literatura. O capítulo 4 engloba a caracterização dos complexos contendo o ligante nitrogenado rígido 4,4’-bipiridina (BIPY). Os complexos (5) e (6) tiveram suas estruturas determinadas por difração de raios X de monocristal. No complexo (5) temos a formação de um composto binuclear onde o ligante nitrogenado BIPY atua em ponte entre os sítios metálicos de Co(II) que por sua vez se encontram coordenados de modo tridentado ao ânion 2,6-piridinodicarboxilato e duas moléculas de água culminando em uma geometria octaédrica para o centro metálico. A natureza 3-D é evidenciada através de ligações de hidrogênio do tipo O – H...O. No composto (6) verifica-se que cada centro metálico adota uma geometria pirâmide de base quadrada na qual a base é formada pelos oxigênio do grupos carboxilato e a posição apical ocupada por um átomo de nitrogênio proveniente do ligante BIPY, que atua em ponte entre os sítios de Cu(II), originando uma cadeia polimérica unidimensional. O presente trabalho revela um grande interesse no estudo da Química Supramolecular, abrangendo importantes conteúdos em Química Inorgânica Supramolecular propondo-se diferentes rotas sintéticas para obtenção das estruturas supramoleculares. / This work describes the synthesis and characterization of transition metal complexes, especially the metallic ions from the first row, Cu2+, Co2+ and Zn2+, containing the 2,6-pyridinedicarboxylate anion as well as the rigid and the flexible nitrogen ligands, 4,4’-bipyridine (BIPY) and 1,3-bis(4-pyridil)propane (BPP). All the compounds were characterized by means of elemental analysis (CHN), thermal analysis (TG), infrared spectroscopy (IR) and single crystal X-ray diffraction analysis. Chapter 1 involves a brief introduction about Coordination Polymers. In addition a presentation about Supramolecular Chemistry, carboxylate anions and nitrogen ligands used in this work, is include enphatizing the intensive research in this area. In chapter 2, the synthesis of the sodium salt derived from the dicarboxylic acid, as well as of the six complexes containing the nitrogen ligands 1,3-bis(4-pyridil)propane and 4,4’-bipyridine are described. These complexes were named [Cu(2,6-PDC)(2,6-PDCH2)].3H2O (1), [Cu2 (μ-BPP) (2,6-PDC)2(H2O)2]. 2H2O (2), {[Co(H2O)4 (BPP)] [Co(2,6-PDC)2]. H2O}n (3) e (H2BPP) [Zn(2,6-PDC)2].4H2O (4), [ Co2 (μ-BIPY) (2,6-PDC)2(H2O)4]. 2H2O (5) e [Cu2(μ-O2CCH2C4H3S)4(Bipy)]n (6). Chapter 3 presents the characterization of the complexes containing the nitrogen ligand 1,3-bis(4-pyridil)propane. Complexes (2) and (3) had their structures determined by single crystal X-ray analysis. Complex (2) is homobimetallic were two Cu(II) centers in a distorted square-piramide geometry, connected by a BPP ligand in the bridging mode. On the other hand, compound (3) presents an anionic moiety, formed by a Co(II) center and two pyridinedicarboxylate anions and a cationic polymeric chain, formed by Co(II) ions and bridging BPP ligands. In both cases, a 3-D supramolecular array is generated through hydrogen bondings. The analytical and spectroscopic data for compound (4) suggest the formation of an ionic complex, in which the anionic moiety contains two 2,6-pyridinedicarboxylate anions coordinated to the Zn(II) center in the tridentate (ONO) fashion. The nitrogen ligand BPP is protonated, (H2BPP2+) estabilizing the anionic unit. This type of structure is well supported by several examples from literature. Chapter 4 describes the characterization of the complexes containing the rigid nitrogen ligand 4,4’-bipyridine (BIPY). Complexes (5) and (6) have had their structures determined by single crystal X-ray diffraction analysis. Complex (5) is homobinuclear in which the nitrogen ligand BIPY bridges two Co(II) sites that are also coordinated by 2,6-pyridinedicarboxylate anion in the tridentate mode as well as by two water molecules, in an distorted octahedral geometry. The 3-D supramolecular nature of the system is achievied through O – H…O hydrogen bondings. In compound (6) it can be noticed that each metal center adopts the distorted square-pyramide geometry in which the base is formed by the oxygen atoms from the carboxylate groups and the apical positions is occupied by nitrogen atom from BIPY ligand. The BIPY ligands bridge the Cu(II) sites, generating a one-dimensional polymeric chain. This work shows a great interest in the study of Supramolecular Chemistry, covering important content in Supramolecular Inorganic Chemistry proposing different synthetic routes to obtain of the supramolecular structures.

No description available.

Two series of stable palladium and silver complexes ligated to hemilabile ligands were prepared. The stability and applicability of these well-defined complexes in promoting various reactions (cycloaddition, hydroamination, cross-coupling reactions, etc.) was investigated. Structure-activity studies with a series of related ligands led us to find a pronounced ligand effect on these reactions. The dichotomous reactivity of triethyl phosphonium hydrobromide salt with dialkyl acetals was used for the synthesis of alkoxy phosphonium salts. Reactivity and applications of these phosphonium salts were described for the synthesis of the biologically active cinnamyl triazoles and ethyl indole-2-carboxylates. Total synthesis of the natural product nostodione A, was developed in eight chemical steps and with 21.6% overall yield from ethyl-2-indolecarboxylates. The synthesis of a mini-panel of structural analogs allowed for the discovery of anti-parasitic biological activity of nostodione A and its analogues for the first time. / Thesis / Doctor of Science (PhD)

Dans ce travail de thèse, plusieurs approches ont été développées pour permettre une utilisation plus variée des carbènes N-hétérocycliques (NHCs) et des phosphines en tant que catalyseurs/activateurs organiques.Les précurseurs de NHCs étudiés dans un premier temps, c'est-à-dire les hydrogénocarbonates d’azolium, peuvent être synthétisés en une seule étape, à l’inverse des NHCs dont la synthèse et l’isolation sont souvent compliquées. Nous avons démontré que ces espèces sont stables à l’air et sont à l’équilibre en solution avec leurs homologues carboxylates d’azolium (adduits NHC-CO2). Leur utilisation permet donc de faciliter la manipulation des NHCs tout en conservant une activité catalytique satisfaisante tant en synthèse moléculaire qu’en chimie des polymères.Des paires de Lewis silane ou borane/NHC ont ensuite été employées afin d’augmenter le potentiel des NHCs pour des réactions “modèles” de chimie (macro)moléculaire par un effet de double assistance (acide/base de Lewis).Enfin, une phosphine commerciale a été utilisée pour catalyser la polymérisation par transfert de groupe des (méth)acrylates d’alkyle de façon “vivante/contrôlée”. / In this thesis work, some points are adressed in order to broaden the scope of the application of N-heterocyclic carbenes (NHCs) as organic catalysts/activators.The novel NHC precursors studied first, i.e. azolium hydrogen carbonates, are synthesized in a one-step undemanding process, in contrast to NHCs whose synthesis and isolation is often a tedious procedure. We then showed that these species are air-stable and are at the equilibrium, in solution, with their azolium-2-carboxylates homologues (NHC-CO2 adducts). The use of such precatalysts thus allows facilitating the manipulation of NHCs, while maintaining an efficient catalytic activity in molecular chemistry as well as in polymer synthesis.We then proposed to use NHCs in conjunction with organic Lewis acids (silanes or boranes) as a possible means to induce a cooperative dual activation mechanism (Lewis acid/base) in order to increase the potential of NHCs for “model” (macro)molecular reactions.Finally, a commercial phosphine was used to trigger the group transfer polymerization of alkyl (meth)acrylates in a “controlled/living” fashion.

La flottation des particules fines est un challenge technique que l’industrie minière doit relever pour pouvoir exploiter de manière optimale certains types de gisement dont les minerais présentent des textures particulièrement fines. Cette problématique revêt une importance particulière avec la diminution des ressources minérales considérées comme conventionnelles du point de vue de la maille de libération des minéraux d’intérêt. Il existe deux manières d’optimiser les procédés de flottation pour un minerai, la recherche des paramètres de fonctionnement optimaux des équipements de flottation existants et l'élaboration de nouveaux réactifs de flottation. Les travaux des dernières décennies ont mis en évidence qu’en raison de leurs hauts régimes hydrodynamiques favorisant le contact entre les bulles et les particules, les techniques de flottation intensive étaient beaucoup plus adaptées pour le traitement des fines que les dispositifs de flottation mécanique. Cependant, en raison du temps de résidence très court au sein de ces dispositifs de flottation, il est nécessaire que la surface des minéraux d’intérêts soit rendue particulièrement hydrophobe. En ce sens, l’amélioration des performances de flottation, pour les minerais à granularité réduite, par des techniques de flottation intensive requiert l’élaboration de réactifs de flottation plus efficaces et plus sélectifs. L’objet d’étude qui a été choisi est un résidu fin produit à l’issue des différentes étapes nécessaires à l’extraction de l’or et du tellure à partir du minerai de la mine de Kankberg en Suède. Ce résidu à granularité fine possède une faible teneur en terres rares présentes sous la forme de monazite, un minéral de type phosphate. Les travaux de thèse présentés dans ce manuscrit consistaient à développer un réactif permettant d’améliorer l’adsorption d’un collecteur sur la surface de la monazite pour faciliter sa récupération lors de la flottation intensive. Il ressort de ces études que les ions lanthane peuvent améliorer significativement l’adsorption des collecteurs de type carboxylate sur la surface de la monazite et donc améliorer la flottabilité de cette dernière. Les connaissances actuelles concernant les propriétés de surface de la monazite et les mécanismes d’adsorption des collecteurs anioniques sur la surface de ce minéral sont relativement limitées. Il paraissait donc judicieux de contribuer au cours de cette thèse à l’amélioration de ces connaissances. Une étude a été menée pour évaluer l’hydroxylation de surface de la monazite qui est largement considérée dans la littérature comme influençant l’adsorption du collecteur. La manipulation de monazite peut conduire à une exposition aux radiations en raison de la radioactivité émise par la chaîne de désintégration des actinides souvent présents en quantité significative dans le réseau cristallin de la monazite. Au cours de ce projet doctoral, la synthèse de matériaux indurés analogues à la monazite a également été étudiée dans le but de faciliter le déroulement des expérimentations qui nécessitent l’utilisation de monazite. Un protocole de synthèse de poudre de monazite suffisamment indurée pour être agitée a été développé. Des mesures de mobilité électrophorétiques ont par ailleurs montré que les propriétés de surface de ces monazites de synthèse sont identiques à celles d’une monazite naturelle à composition complexe démontrant par ailleurs que la présence de nombreuses substitutions atomiques dans le réseau cristallin de la monazite n’avait pas d’influence sur sa mobilité électrophorétique. / The flotation of fine particles is a technical challenge that the mining industry must address to efficiently exploit certain types of deposit whose ores are finely textured. This issue is of particular importance with the depletion of mineral resources considered as “conventional” with regards to the liberation mesh of minerals of interest. There are two basic approaches to optimise the flotation process for a particular ore, the research for the best working parameters of existing flotation devices and the development of new flotation reagents. The research works in the past decades highlight that, owing to their high hydrodynamic regimes, intensive flotation technologies are more adapted to the treatment of fine particles than conventional mechanical flotation devices. However, due to the short residence time in intensive flotation cells, it is essential that the surface of the minerals of interest has been particularly hydrophobised. In this sense, the improvement of the flotation performance for fine grained ores implies both the use of new flotation technologies and the development of more efficient and more selective flotation reagents. The selected object of studies is a fine grained residue produced after the extraction of gold and tellurium out of the ore from the Kankberg mine which is located in Sweden. This fine material contains low amounts of rare earth elements, in the form of monazite, a phosphate mineral. The thesis works presented in this manuscript consists of developing a reagent that improves the adsorption of the collector on the surface of monazite to facilitate its recovery throughout intensive flotation. The conducted studies emphasise that lanthanum ions significantly promote the adsorption of carboxylate type collectors on the monazite surface thereby increasing the floatability of this mineral. Current knowledge regarding the surface properties of monazite and the mechanism of anionic collectors adsorption on the monazite surface are relatively limited. Therefore, it seems wise to contribute to improving this knowledge during this thesis. A study was carried out to assess the hydroxylation of the monazite surface which is largely considered in the literature as a phenomenon influencing the collector adsorption. The handling of monazite may cause radiation exposure because of the radioactive decay chains of the actinide elements naturally present in the monazite crystal lattice. During this thesis, the synthesis of indurated monazite analogue materials was also investigated to facilitate the conduct of experiments. A protocol of synthesis of monazite powder sufficiently indurated to be mechanically stirred has been developed. Electrophoretic mobility measurements highlight that the surface properties of the synthetic monazite materials were similar to those of natural monazite with complex chemistry showing, in addition, that the presence of several atom substitutions in the monazite crystal lattice has no influence on its electrophoretic mobility.

Compostos do tipo [M2(O2CR)4] com ligação múltipla direta entre os centros metálicos apresentam importância do ponto de vista teórico bem como da química aplicada a diversas áreas. Recentemente tem havido um grande interesse voltado, especialmente, para o design de novos materiais construídos com base nestas unidades dimetálicas. O principal objetivo deste trabalho é o estudo de complexos de rutênio que apresentam núcleos M2 de valência mista do tipo Ru2(lI,III) com ligantes dicarboxílicos. A partir do complexo [Ru2(OAc)4CI], foram sintetizados compostos com os ligantes dicarboxilatos -O2C-R-CO2-, em que R são cadeias carbônicas saturadas (succinato, adipato e dodecanodioato) ou anéis aromáticos (tereftalato e 4,4\'-bifenildicarboxilato). Modificando-se a metodologia de síntese, foi possível isolar dois tipos de compostos: [Ru2(O2C-R-CO2)2CI] (R = succ, adip, dode, tere e bife) e [Ru4(O2C-R-CO2)5(H2O) 2] (R = adip e dode). Todos os compostos apresentam bandas de absorção na região do visível, ao redor de 450 nm, e do infravermelho próximo, ao redor de 1100 nm, que podem ser atribuídas, respectivamente às transições eletrônicas π (Ru-O, Ru2) → π* (Ru2) e δ (Ru2) → δ* (Ru2). Estas transições são características de espécies de [Ru2]5+, comprovando a manutenção das ligações metal-metal nos derivados. Os valores dos momentos magnéticos efetivos (µeff), calculados com base em medidas de susceptibilidade magnética, estão na faixa de 3,8-4,4 M.B para os compostos [Ru2(O2C-R-CO2)2CI] (R = succ, adip e dode) e correspondem à configuração eletrônica do estado fundamental do tipo σ2 µ4 δ2 (µ*)2 (δ *)1, com três elétrons desemparelhados, que é observada para carboxilatos de dirutênio (lI,III). Valores de µeff um pouco mais altos foram obtidos para os demais compostos, provavelmente devido à existência de algum tipo de acoplamento magnético. Nos espectros vibracionais FT-IR, observam-se bandas na faixa de 1470 a 1390 cm-1, que é típica das frequências de estiramentos νa e νs dos grupos COO- de carboxilatos ligados em ponte. Bandas relativas às frequências de estiramento das ligações metal-metal, ν(Ru-Ru), são observadas nos espectros Raman ao redor de 330 cm-1. Estes dados indicam que os compostos apresentam estruturas do tipo gaiola em que os ligantes carboxilatos formam pontes equatoriais (via grupo COO-) entre dois íons metálicos, estabilizando a ligação múltipla Ru-Ru. Devido à presença de dois grupos COO- para cada íon dicarboxilato, ocorre também a formação de pontes equatoriais entre centros de [Ru2]5+, gerando espécies poliméricas constituídas por unidades [Ru2(O2C-R-CO2)2]+. As posições axiais são ocupadas pelos ânions cloreto ou carboxilato, respectivamente nos casos dos compostos [Ru2(O2C-R-CO2)2CI] e [Ru4(O2C-R-CO2)5(H2O)2], que também formam pontes entre unidades dimetálicas. As presenças das pontes axiais e das pontes equatoriais entre unidades de [Ru2]5+ gerando estruturas tridimensionais que apresentam dois tipos distintos de lamelas ou camadas foram comprovadas com base nos valores das distâncias interplanares calculadas a partir dos difratogramas de raios-X de pó dos compostos. Os compostos são termicamente estáveis até a temperatura de ~ 250°C, conforme verificado por meio de estudos de análise termogravimétrica. Acima desta temperatura, começam a ocorrer perdas de massa que correspondem às perdas totais dos ligantes equatoriais e axiais, considerando-se o RuO2 como produto final das decomposições térmicas. Os compostos [Ru2(adip)2CI], [Ru2(tere)2CI] e [Ru4(dode)5(H2O)2] apresentam áreas superficiais elevadas, aproximadamente iguais a 170, 100 e 40 m2/g, respectivamente, que podem estar relacionadas à formação de estruturas microporosas. Estes tipos de estruturas com poros podem atuar como adsorvedores de gases, por exemplo, o que torna os compostos bastante promissores para aplicação na área de novos materiais microporosos, especialmente o primeiro cuja área é cerca de duas vezes maior do que a do segundo, o qual está descrito na literatura como bom adsorvedor para N2, O2 e Ar. / Compounds containing dimetal units [M2(O2CR)4] which have metal-metal multiple bonds are of great interest in both theoretical and applied chemistry. Recently they have been investigated as important compounds for the design of new materiaIs. The main goal of this work is the study of mixed valent diruthenium carboxylates. Compounds formed by Ru2(II,III) centers and -O2C-R-CO2- dicarboxylate ligands, where R is a saturated carbon chain (succinate, adipate and dodecanodioate) or aromatic ring (terephthalate and 4,4\'-diphenyldicarboxylate), were synthesized. Two types of compounds were obtained depending on the synthetic methodology: [Ru2( O2C-R-CO2)2CI] (R = succ, adip, dode, tere and bife) and [Ru4(O2C-R-CO2)5(H2O) 2] (R = adip and dode). AlI compounds exhibit absorption bands in the visible region, around 450 nm, and in the near infrared, around 1100 nm, which can be ascribed respectively to the π (Ru-O, Ru2) → π* (Ru2) and δ (Ru2) → δ* (Ru2) electronic transitions. These are characteristic of [Ru2]5+ dimetal species, indicating that the metal-metal bonds are present in the derivatives. The effective magnetic moments (µeff) values calculated from magnetic susceptibilities data are in the range of 3.8 - 4.4 B.M. for the [Ru2(O2C-R-CO2)2CI] (R = succ, adip and dode) compounds, corresponding to the σ2 µ4 δ2 (µ*)2 (δ *)1 ground state electronic configuration, with three unpaired electrons, that is observed for diruthenium (II,III) carboxylates. Higher µeff values found for the other compounds can be due to some type of magnetic coupling. The FT-IR vibrational spectra show characteristic bands in the region of 1470 1390 cm-1 that is typical of symmetric and asymmetric bridging carboxylate stretching modes. The metal-metal stretching modes, ν (Ru-Ru), are observed in the Raman spectra around 330 cm-1. Based on these results, it can be proposed that the compounds exhibit \'lantern\' type structures where the carboxylate ligands bridge two metal ions equatorially by COO- groups, stabilizing the Ru-Ru multiple bound. Due to the presence of two COO- groups for each dicarboxylate ion, there is the occurrence of equatorial bridges between [Ru2]5+ centers too, generating polymeric species constituted by [Ru2(O2C-R-CO2)2]+ units. The chloride or the carboxylate anionic axial ligands, respectively in [Ru2(O2C-R-CO2)2CI] and [Ru4(O2C-R-CO2)5(H2O)2] compounds, can also bridge the dimetal units in the axial direction. The existence of these axial and equatorial bridges between [Ru2]5+ units generate tridimensional network structures that exhibit two different types of layers, as shown by the analysis of the interplanar distances calculated from powder X-ray diffiaction of the solids. The compounds are thermally stable up to 250°C as indicated by thermogravimetric analysis. Above this temperature, there are losses of mass that correspond to the total losses of the equatorial and the axial ligands considering the RuO2 as the product of thermal decomposition. The [Ru2(adip)2CI], [Ru2(tere)2CI] and [Ru4(dode)5(H2O)2] compounds exhibit large superficial areas, about 170, 100 and 40 m2/g respectively, which could be indicative of microporous structures. These kinds of porous structures can be used as adsorbents for gases, for example. It makes the compounds very interesting for application as new microporous materiaIs, specially for the former which has a superficial area twice as bigger as the second one that is described in the literature as good adsorbent for N2, O2e Ar.

Este trabalho investigou a influência de diferentes solventes na liberação fotoinduzida do monóxido de carbono a partir do complexo [Ru3O(CH3COO)6(CO)(dmpz)2] (dmpz = 2,6-dimetilpirazina),e o comportamento solvatocrômico deste mesmo complexo e dos análogos [Ru3O(CH3COO)6(ampy)2(CO)] (ampy = 4-aminopiridina) e [Ru3O(CH3COO)6(py)2(CO)] (py = piridina). O complexo [Ru3O(CH3COO)6(CO)(dmpz)2] foi irradiado com laser em 377 nm em soluções de hexano, diclorometano, acetonitrila, metanol, etanol, 1-butanol, acetona, dimetilsulfóxido, água e tampão tris (pH=7,4).Estas irradiações foram acompanhadas por espectroscopia na região do UV-visível e o rendimento quântico da liberação fotoinduzida de monóxido de carbono foi calculado por meio de actinometria química de tris oxalato ferrato (III) de potássio. Com este estudo notou-se que o fotoproduto obtido depende do solvente utilizado, porém o rendimento quântico de liberação de CO não variou de forma significativa nos diferentes meios, indicando um mecanismo dissociativo no processo. Cálculos de TD-DFT para o complexo supracitado mostraram que,embora o complexo seja neutro, seu estado fundamental é mais polar do que seu estado excitado de transferência de carga, porém a diferença de polaridade entre os estados não foi considerada extensa. Análises do comportamento solvatocrômico dos complexos [Ru3O(CH3COO)6(ampy)2(CO)], [Ru3O(CH3COO)6(CO)(dmpz)2] e [Ru3O(CH3COO)6(CO)(py)2] também foram realizadas. Observou-se que cada composto apresentou um comportamento diferente, indicando a influência dos grupos substituintes nos ligantes terminais nas propriedades destes compostos. O complexo [Ru3O(CH3COO)6(ampy)2(CO)] apresentou deslocamento batocrômico da banda de transferência de carga do cluster para ligante (TCCL) com o aumento da polaridade dos solventes devido as características básicas do ligante terminal. Além de mostrar dependência com os solventes próticos utilizados, por conta das ligações de hidrogênio formadas entre o grupo amina do ligante e os solventes, bem como solvatação preferencial por metanol em misturas contendo este solvente prótico. O composto [Ru3O(CH3COO)6(CO)(dmpz)2], por sua vez, apresentou deslocamento hipsocrômico da banda TCCL com o aumento da polaridade dos solventes por conta das propriedades ácidas do ligante terminal e não apresentou dependência com solventes próticos, devido o impedimento estérico existente do nitrogênio não coordenado do ligante. Como esperado, o complexo [Ru3O(CH3COO)6(CO)(py)2] apresentou comportamento intermediário, pelo fato do ligante apresentar natureza intermediária dentro da série utilizada e não conter nenhum grupo substituinte / This work investigated the influence of different solvents on the photoinduced release of carbon monoxide from the complex [Ru3O(CH3COO)6(CO)(dmpz)2] (dmpz= 2,6 dimethylpyrazine), and the solvatocromic behavior of this same complex and the analogs [Ru3O(CH3COO)6(ampy)2(CO)] (ampy = 4-aminopyridine) and [Ru3O(CH3COO)6((CO)(py)2] (py = pyridine). The complex [Ru3O(CH3COO)6(CO)(dmpz)2] was irradiated by a laser at 377 nm in hexane, dichloromethane, acetonitrile, methanol, ethanol, 1-butanol, acetone, dimethylsulfoxide, water and tris buffer (pH = 7,4).These irradiations were accompanied by spectroscopy in the UV-Vis region and the quantum yield of the photoinduced release of carbon monoxide was calculated by chemical actinometry of potassium ferroxalate. By this study, it was observed that the photoproduct depends on the solvent used, but the quantum yield of CO release did not vary significantly in the different media used, indicating a dissociative mechanism in the process. TD-DFT calculations for the aforementioned complex have shown that although the complex is neutral, its ground state is more polar than its excited state of charge transfer, however the polarity difference between the states was not considered extensive. Analysis of the solvatocromic behavior of the complexes [Ru3O(CH3COO)6(ampy)2(CO)], [Ru3O(CH3COO)6(CO)(dmpz)2] and [Ru3O(CH3COO)6(CO)(py)2] were also performed. It was observed that each compound had a different behavior, indicating the influence of the substituent groups on the terminal ligands on the properties of these compounds. The [Ru3O(CH3COO)6(ampy)2(CO)] complex exhibited bathochromic shift of the charge transfer transition (CT) with increasing solvent polarity due to the basic characteristic of the terminal ligand. It also showed dependence with the protic solvents used, due to the hydrogen bonds formed between the amine group of the ligand and the solvents, as well as preferential salvation by methanol in mixtures containing this protic solvent.The compound [Ru3O(CH3COO)6(CO)(dmpz)2], on the other hand, presented a hypochromic shift of the charge transfer band with the increase of the polarity of the solvents due to the acidic properties of the terminal ligand and no dependence on protic solvents due to the steric hindrance of the uncoordinated nitrogen of the ligand. As expected, the [Ru3O(CH3COO)(CO)(py)2] complex exhibited intermediate behavior because the ligand has an intermediate nature within the series used an does not contain any substituent groups

Este trabalho investigou a influência de diferentes solventes na liberação fotoinduzida do monóxido de carbono a partir do complexo [Ru3O(CH3COO)6(CO)(dmpz)2] (dmpz = 2,6-dimetilpirazina),e o comportamento solvatocrômico deste mesmo complexo e dos análogos [Ru3O(CH3COO)6(ampy)2(CO)] (ampy = 4-aminopiridina) e [Ru3O(CH3COO)6(py)2(CO)] (py = piridina). O complexo [Ru3O(CH3COO)6(CO)(dmpz)2] foi irradiado com laser em 377 nm em soluções de hexano, diclorometano, acetonitrila, metanol, etanol, 1-butanol, acetona, dimetilsulfóxido, água e tampão tris (pH=7,4).Estas irradiações foram acompanhadas por espectroscopia na região do UV-visível e o rendimento quântico da liberação fotoinduzida de monóxido de carbono foi calculado por meio de actinometria química de tris oxalato ferrato (III) de potássio. Com este estudo notou-se que o fotoproduto obtido depende do solvente utilizado, porém o rendimento quântico de liberação de CO não variou de forma significativa nos diferentes meios, indicando um mecanismo dissociativo no processo. Cálculos de TD-DFT para o complexo supracitado mostraram que,embora o complexo seja neutro, seu estado fundamental é mais polar do que seu estado excitado de transferência de carga, porém a diferença de polaridade entre os estados não foi considerada extensa. Análises do comportamento solvatocrômico dos complexos [Ru3O(CH3COO)6(ampy)2(CO)], [Ru3O(CH3COO)6(CO)(dmpz)2] e [Ru3O(CH3COO)6(CO)(py)2] também foram realizadas. Observou-se que cada composto apresentou um comportamento diferente, indicando a influência dos grupos substituintes nos ligantes terminais nas propriedades destes compostos. O complexo [Ru3O(CH3COO)6(ampy)2(CO)] apresentou deslocamento batocrômico da banda de transferência de carga do cluster para ligante (TCCL) com o aumento da polaridade dos solventes devido as características básicas do ligante terminal. Além de mostrar dependência com os solventes próticos utilizados, por conta das ligações de hidrogênio formadas entre o grupo amina do ligante e os solventes, bem como solvatação preferencial por metanol em misturas contendo este solvente prótico. O composto [Ru3O(CH3COO)6(CO)(dmpz)2], por sua vez, apresentou deslocamento hipsocrômico da banda TCCL com o aumento da polaridade dos solventes por conta das propriedades ácidas do ligante terminal e não apresentou dependência com solventes próticos, devido o impedimento estérico existente do nitrogênio não coordenado do ligante. Como esperado, o complexo [Ru3O(CH3COO)6(CO)(py)2] apresentou comportamento intermediário, pelo fato do ligante apresentar natureza intermediária dentro da série utilizada e não conter nenhum grupo substituinte / This work investigated the influence of different solvents on the photoinduced release of carbon monoxide from the complex [Ru3O(CH3COO)6(CO)(dmpz)2] (dmpz= 2,6 dimethylpyrazine), and the solvatocromic behavior of this same complex and the analogs [Ru3O(CH3COO)6(ampy)2(CO)] (ampy = 4-aminopyridine) and [Ru3O(CH3COO)6((CO)(py)2] (py = pyridine). The complex [Ru3O(CH3COO)6(CO)(dmpz)2] was irradiated by a laser at 377 nm in hexane, dichloromethane, acetonitrile, methanol, ethanol, 1-butanol, acetone, dimethylsulfoxide, water and tris buffer (pH = 7,4).These irradiations were accompanied by spectroscopy in the UV-Vis region and the quantum yield of the photoinduced release of carbon monoxide was calculated by chemical actinometry of potassium ferroxalate. By this study, it was observed that the photoproduct depends on the solvent used, but the quantum yield of CO release did not vary significantly in the different media used, indicating a dissociative mechanism in the process. TD-DFT calculations for the aforementioned complex have shown that although the complex is neutral, its ground state is more polar than its excited state of charge transfer, however the polarity difference between the states was not considered extensive. Analysis of the solvatocromic behavior of the complexes [Ru3O(CH3COO)6(ampy)2(CO)], [Ru3O(CH3COO)6(CO)(dmpz)2] and [Ru3O(CH3COO)6(CO)(py)2] were also performed. It was observed that each compound had a different behavior, indicating the influence of the substituent groups on the terminal ligands on the properties of these compounds. The [Ru3O(CH3COO)6(ampy)2(CO)] complex exhibited bathochromic shift of the charge transfer transition (CT) with increasing solvent polarity due to the basic characteristic of the terminal ligand. It also showed dependence with the protic solvents used, due to the hydrogen bonds formed between the amine group of the ligand and the solvents, as well as preferential salvation by methanol in mixtures containing this protic solvent.The compound [Ru3O(CH3COO)6(CO)(dmpz)2], on the other hand, presented a hypochromic shift of the charge transfer band with the increase of the polarity of the solvents due to the acidic properties of the terminal ligand and no dependence on protic solvents due to the steric hindrance of the uncoordinated nitrogen of the ligand. As expected, the [Ru3O(CH3COO)(CO)(py)2] complex exhibited intermediate behavior because the ligand has an intermediate nature within the series used an does not contain any substituent groups