Polyoxometalates (POMs) are a class of transition-metal oxide clusters with significant applications in material science as well as in the biomedical field. Recently, it has been reported that POMs exhibit antitumor activity. POMs containing molybdenum (Mo), tungsten (W), and vanadium (V) with oxygen are three types of POMs with different structural features introduced by our lab as a novel inorganic chemotherapeutic agent for cancer treatment. In this study, Vanadium polyoxometalate (V-POM), which exhibited highest cytotoxicity in 5 different cancer cell lines in in vitro experiment, will be incorporated with Gelatin type B through polymer modification in hopes of prolonging circulation time and avoiding undesired toxicity. The stability, cellular uptake, and cytotoxicity of the V6-POM/Gelatin nanoparticles will be investigated in vitro. The reported study indicates the feasibility of using V6-POM/gelatin nanoparicles for anticancer applications.

No description available.

Carbon materials are commonly studied as the electrode material for electrochemical double layer capacitance (EDLC) due to their high surface area. The present work aimed to leverage both EDLC and pseudocapacitance through chemical modification of multi-wall carbon nanotubes (MWCNTs) and onion-like carbon (OLC) with polyoxometalates (POMs) to further enhance the performance of these electrodes. Layer-by-layer (LbL) deposition of two commercially available POMs (PMo12O403- and SiMo12O404-) and three synthesized POMs (PMo11VO404-, PMo10V2O405- and PMo9V3O406-) has been investigated. A single-layer of POMs increased the area specific capacitance by approximately three-times, while superimposing of these POMs into two-layer coatings increased the capacitance by approximately five-times. The morphology and composition of these composite materials were investigated using Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS).

Carbon materials are commonly studied as the electrode material for electrochemical double layer capacitance (EDLC) due to their high surface area. The present work aimed to leverage both EDLC and pseudocapacitance through chemical modification of multi-wall carbon nanotubes (MWCNTs) and onion-like carbon (OLC) with polyoxometalates (POMs) to further enhance the performance of these electrodes. Layer-by-layer (LbL) deposition of two commercially available POMs (PMo12O403- and SiMo12O404-) and three synthesized POMs (PMo11VO404-, PMo10V2O405- and PMo9V3O406-) has been investigated. A single-layer of POMs increased the area specific capacitance by approximately three-times, while superimposing of these POMs into two-layer coatings increased the capacitance by approximately five-times. The morphology and composition of these composite materials were investigated using Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS).

Porous materials have exhibited some remarkable performances in wide range of applications such as in the field of catalysis, gas adsorption, water treatment, bio- imaging, drugs delivery and energy applications. This is due to the pore characteristic of these materials. In fact, their properties depend mainly on the pore size, pore morphology and pore size distribution. The knowledge of understanding the effect of chemical nature of porous materials on the heterogeneous catalysis has significantly increased since last decades resulting in the increase in the development of innovative porous nano-hybrid materials. Scientists have integrated inorganic and organic materials to generate new structures with unique properties. A significant enhancement in their properties have been observed compared to their single components. This research work focuses on the design and tailoring of innovative hybrid materials with intrinsic porosity based on well studied single components for catalysis and energy applications. The first example is represented by the impregnation technique of gold nanoclusters (Au NCs) inside the pores of mesoporous silica nanoparticles (MSNs). The performance of Au NCs/ MSN as catalyst was evaluated by the epoxidation reaction of styrene. It shows a remarkable catalytic activity, high selectivity towards styrene epoxide (74%) and high conversion of styrene (88%). We have also investigated the self-assembly of polyoxomolybdates (P2Mo5O23) and cyclodextrins (CDs) as molecular building blocks (MBBs) through the bridging effect of counter cations (Na+, K+, and Cs+). This assembly has resulted in the formation of seven different crystals to give seven crystal structures of POM-CD MOFs. These novel porous hybrid frameworks with intrinsic porosity and tunable porosity have been well studied and characterized using different techniques. Interestingly, one of these structures (K-PMo-γ-CD) was obtained in good yield (70 % based on γ-CD), and was therefore selected to further study the catalytic performance of this type of the hybrid organic-inorganic structures (POM-CD MOFs). The ketalization process of cyclohexanone with glycol using K-PMo-γ-CD as catalysts, have been chosed as module reaction for this study. Our results showed that the material give the best catalytic performance, which reached its maximum conversion of 99.94 %, at 100oC. Finally, the scope of our research have been extended by combining another porous macrocycle, a trianglamine (TA), with the metal cluster complex system (polyoxometalate). This hybrid framework (POM-TA) have been well designed and synthesized based on molecular recognition. A detailed characterization shows that the POM-TA material has high surface area that suggests that it can be suitable as catalyst for some industrial processes. Our research on such organic-inorganic hybrid frameworks represents a promising enrichment in the field of heterogeneous catalysis. This is largely due to the possibility of combining different molecular building blocks to form a hybrid framework with improved properties such as intrinsic porosity, large surface area, and tunable structural properties.

Complexes made by hosts that completely surround their guests provide a mean to stabilize reactive chemical intermediates, transfer biologically active cargo to a diseased cell, and construct molecular scale devices. By the virtue of inorganic host-guest self-assembly, the nucleation processes in the cavity of a {P8W48}-archetype phosphotungstate has afforded a nanoscale 16-GaIII-32-oxo cluster that contain the largest number of GaIII ions yet found in polyoxometalate chemistry. Catalytic activity via thus “Metal-Oxo Cluster within Cluster” Assembly has been preliminarily investigated. Besides, the hybrid aggregates composed of the inorganic {P8W48} and orgainc cyclic moiety has been studied.

Neste trabalho buscou-se produzir filmes de nanopartículas de dióxido de titânio e de nanopartículas de dióxido de titânio contendo o complexo sintetizado undecatungstofosfatomanganês(melamina) suportados em cela tubular de vidro borossiliacato e testar sua reatividade como fotocatalisadores frente à atrazina. Os ensaios de fotodegradação da atrazina foram realizados através de um reator fotocatalítico tendo como fonte de irradiação ultravioleta uma lâmpada de vapor de mercúrio de alta pressão de potência de 125 W desprovida do bulbo externo. A degradação da atrazina ocorrida nos experimentos de fotocatálise heterogênea foram acompanhados através da técnica de Espectroscopia de Absorção na Região do Ultravioleta e Visível (UV-vis) e para as amostras inicíais e finais de cada ensaio foram realizadas medidas de teor de Carbono Orgânico Total (TOC). Assim, foi possível estimar a porcentagem de degradação parcial e de mineralização da atrazina. As porcentagens de degradação obtidas para soluções contendo concentração inicial de 10 ppm de atrazina foram: no caso de filmes de nanopartículas de dióxido de titânio, obteve-se porcentagem de degradação parcial da atrazina de 42,2% a partir da análise de UV-vis e 21,8% de mineralização através da análise de TOC. Para o mesmo sistema após 72 horas, as porcentagens de degradação parcial chegaram a 71,5% a partir da análise de UV-vis e 55,5% de mineralização pela análise de TOC. Para o filme de nanopartículas de dióxido de titânio contendo undecatungstofosfatomanganês(melamina) através da técnica de UV-vis obteve-se uma degradação parcial da atrazina de 44,7% ao final de 12 horas e através da análise de TOC obteve-se 22,4% de mineralização. / In this work, films of titanium oxide nanoparticles and of titanium oxide nanoparticles containing the complex undecatungstophosphatemanganese(melamine) immobilized in a borosilicate glass cylindrical cell were prepared and their reactivity as photocatalyst for atrazine were tested. The photodegradation essays of atrazine were made in a phocatalytic reactor where the ultraviolet irradiation source was one mercury vapor lamp of 125 W without the external bulb. The atrazine degradation in heterogeneous photocatalysis experiments were checked by Ultraviolet and visible spectroscopy (UV-vis) and for first and last samples for each essay were made analysis of Total Organic Carbon (TOC). So, it was possible to estimate the percentage of the partial degradation and mineralization of atrazine. The partial degradation percentages obtained for solutions with initial concentration of 10 ppm of atrazine were: In the case for films of titanium oxide nanoparticles, the partial degradation percentage for atrazine was 42,2% in UV-vis analysis and 21,8% of mineralization obtained by TOC analysis. For the same system after 72 hours, the partial degradation percentages were 71,5% in UV-vis analysis and 55,5% of mineralization obtained by TOC analysis. For the film with titanium oxide nanoparticles containing the complex undecatungstophosphatemanganese(melamine), after 12 hours, the partial degradation of atrazine was 44,7% in UV-vis analysis and 22,4% of mineralization obtained by TOC analysis.

L'objectif de la thèse était la préparation et la caractérisation des catalyseurs hétérogènes à base de polyoxométalates. L'étude mécanistique d'oxydation du méthane jusqu'au méthanol a montré que sur des polyoxométalates supportés sur la silice l'activation C-H a lieu déjà à la température ambiante. L'adsorption du méthane-13C sur H4SiMo12O40 supporté, suivie par RMN solide a mis en évidence la création de l'espèce méthoxy [SiMo12O40(CH3)]3-. Le cycle catalytique est complété par l'hydrolyse de cette espèce - méthanol est formé et une molécule de l'eau recrée la structure du départ de polyoxométalate. L'adsorption du méthanol-13C sur des polyoxométalates a montré la création de deux types des espèces methoxy, localisées sur des atomes d'oxygènes terminaux ou pontants est caractérisées par deux signaux RMN distincts - à 58 et 77 ppm, respectivement. En greffant un complexe de platine PtMe2COD sur les sels de césium de polyoxometalates, le dégagement du méthane ou de la mélange du méthane et de l'éthane a été observé et expliqué par la séquence de l'addition oxydative du proton de polyoxometalate au centre métallique, couplage C-H ou C-C et finalement l'élimination réductrice et libération d'une molécule de gaz. Sels d'ammonium de l'acide phosphotungstique H3PW12O40 ont été montrées de catalyser l'isomérisation du n-butane a l'isobutane dans des conditions douces (225°C, 1 atm.). Composé du cuivre Cu(OTf)2 sur la surface des sels inorganiques des polyoxometalates donne des catalyseurs très actifs en insertion des carbènes aux liaisons C-H des éthers cycliques.

Giant Polyoxometalates : Dynamic Structure and Reactivity. In this thesis different methods were used to study several systems in which giant polyoxometalates are involved. The validity of the theoretical methods applied and the results obtained were always contrasted with the experimental evidence provided by the groups of Prof. Achim Müller (Bielefeld) and Prof. Marcella Bonchio (Padova). In certain cases the theoretical results provided an explanation for experimental observations and in other cases they had allowed prediction as main objective.Chapter IV presents the results regarding encapsulated water molecules inside the giant polyoxometalate cavities. Chapter V presents the results of the studies about ion pairing on polyoxometalates. Chapters VI and VII presents the results of two different polyoxometalates and their catalytic activity. Finally Chapter VIII presents a theoretical study on the effect of counterions on the growth of giant uranium polyperoxometalates. / Polioxometal·lats Gegants: Estructura Dinàmica i Reactivitat.En la present tesi diferents mètodes han estat utilitzats per estudiar diversos sistemes on els polyoxometalats gegants juguen un paper fonamental. La validesa dels mètodes computacionals utilitzats i dels resultats obtinguts han estat sempre contrastats amb les evidencies experimentals facilitades pels grups del Prof. Achim Müller (Bielefeld) i Prof. Marcella Bonchio (Padova). En alguns casos els resultats computacionals han permès explicar les observacions experimentals i en d'altres han permet fer prediccions com a principal objectiu.En el capítol IV es presenten els resultats referents a l'estructura de l'aigua encapsulada en les cavitats presents a polioxometal·lats gegants. El capítol V presenta els resultats dels estudis sobre ion pairing en polioxometal·lats. Els capítols VI i VII presenten els resultats de dos sistemes diferents i la seva activitat com a catalitzadors. Finalment, el capítol VIII presenta un estudi teòric sobre l'efecte dels contraions en el creixement de poliperoxometal·lats gegants d'urani.

Neste trabalho buscou-se produzir filmes de nanopartículas de dióxido de titânio e de nanopartículas de dióxido de titânio contendo o complexo sintetizado undecatungstofosfatomanganês(melamina) suportados em cela tubular de vidro borossiliacato e testar sua reatividade como fotocatalisadores frente à atrazina. Os ensaios de fotodegradação da atrazina foram realizados através de um reator fotocatalítico tendo como fonte de irradiação ultravioleta uma lâmpada de vapor de mercúrio de alta pressão de potência de 125 W desprovida do bulbo externo. A degradação da atrazina ocorrida nos experimentos de fotocatálise heterogênea foram acompanhados através da técnica de Espectroscopia de Absorção na Região do Ultravioleta e Visível (UV-vis) e para as amostras inicíais e finais de cada ensaio foram realizadas medidas de teor de Carbono Orgânico Total (TOC). Assim, foi possível estimar a porcentagem de degradação parcial e de mineralização da atrazina. As porcentagens de degradação obtidas para soluções contendo concentração inicial de 10 ppm de atrazina foram: no caso de filmes de nanopartículas de dióxido de titânio, obteve-se porcentagem de degradação parcial da atrazina de 42,2% a partir da análise de UV-vis e 21,8% de mineralização através da análise de TOC. Para o mesmo sistema após 72 horas, as porcentagens de degradação parcial chegaram a 71,5% a partir da análise de UV-vis e 55,5% de mineralização pela análise de TOC. Para o filme de nanopartículas de dióxido de titânio contendo undecatungstofosfatomanganês(melamina) através da técnica de UV-vis obteve-se uma degradação parcial da atrazina de 44,7% ao final de 12 horas e através da análise de TOC obteve-se 22,4% de mineralização. / In this work, films of titanium oxide nanoparticles and of titanium oxide nanoparticles containing the complex undecatungstophosphatemanganese(melamine) immobilized in a borosilicate glass cylindrical cell were prepared and their reactivity as photocatalyst for atrazine were tested. The photodegradation essays of atrazine were made in a phocatalytic reactor where the ultraviolet irradiation source was one mercury vapor lamp of 125 W without the external bulb. The atrazine degradation in heterogeneous photocatalysis experiments were checked by Ultraviolet and visible spectroscopy (UV-vis) and for first and last samples for each essay were made analysis of Total Organic Carbon (TOC). So, it was possible to estimate the percentage of the partial degradation and mineralization of atrazine. The partial degradation percentages obtained for solutions with initial concentration of 10 ppm of atrazine were: In the case for films of titanium oxide nanoparticles, the partial degradation percentage for atrazine was 42,2% in UV-vis analysis and 21,8% of mineralization obtained by TOC analysis. For the same system after 72 hours, the partial degradation percentages were 71,5% in UV-vis analysis and 55,5% of mineralization obtained by TOC analysis. For the film with titanium oxide nanoparticles containing the complex undecatungstophosphatemanganese(melamine), after 12 hours, the partial degradation of atrazine was 44,7% in UV-vis analysis and 22,4% of mineralization obtained by TOC analysis.