Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-06-14T19:53:37Z No. of bitstreams: 1 AnaKarinaPereiraLeite_DISSERT.pdf: 3134726 bytes, checksum: 98310bd9f7d887f28ee1f7167205ada0 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-06-15T22:28:23Z (GMT) No. of bitstreams: 1 AnaKarinaPereiraLeite_DISSERT.pdf: 3134726 bytes, checksum: 98310bd9f7d887f28ee1f7167205ada0 (MD5) / Made available in DSpace on 2016-06-15T22:28:23Z (GMT). No. of bitstreams: 1 AnaKarinaPereiraLeite_DISSERT.pdf: 3134726 bytes, checksum: 98310bd9f7d887f28ee1f7167205ada0 (MD5) Previous issue date: 2014-01-24 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / As redes metalorg?nicas (MOFs) s?o h?bridos, normalmente cristalinos, constitu?dos de subunidades inorg?nicas, metais ou clusters met?licos, conectados por ligantes org?nicos polit?picos de forma repetitiva originando estruturas em duas ou tr?s dimens?es, geralmente porosas. Neste trabalho foram sintetizadas MOFs com ?ons lantan?deos (La3+ e Gd3+) e ligantes tipo dicarboxilatos (?cidos isoft?lico e o tereft?lico) pelos m?todos hidrot?rmico, solvot?rmico e hidro(solvo)t?rmico. Os efeitos da rota sint?tica sobre a estrutura e propriedades das MOFs foram estudados, bem como do tipo de aquecimento, convencional ou por microondas. As amostras obtidas na forma de p?s foram caracterizadas por difra??o de raios-X, espectroscopia de infravermelho, analises t?rmicas e microscopia eletr?nica de varredura. Os resultados sugerem a necessidade de uma base, org?nica ou inorg?nica, para promover a desprotona??o do ligante, uma vez que nas amostras preparadas pelo m?todo hidrot?rmico, sem o aux?lio de uma base, n?o houve forma??o de uma rede metalorg?nica. Por outro lado, a presen?a de DMF, como solvente ou co-solvente, proporcionou a desprotona??o do ligante com consequente forma??o das MOFs. Pelo menos duas estruturas cristalinas diferentes foram identificadas para as amostras preparadas com ?cido tereft?lico. Estas amostras apresentam isoestruturas semelhantes ?s reportadas para as fases Eu(1,4-BDC)DMF e Tb(1,4-BDC)H2O. A presen?a de ?gua no meio reacional, m?todo hidro(solvo)t?rmico, direcionou o crescimento da estrutura de maneira diferente da observada quando em sua aus?ncia. Isto pode ser justificado pela diferen?a na forma de coordena??o dos ?ons lantan?deos por ?gua e por DMF. Apesar de n?o terem sido identificadas por DRX, as amostras preparadas com ?cido isoft?lico tamb?m apresentam estruturas metalorg?nicas, confirmadas pelo deslocamento da banda referente ao estiramento do grupo carbonila em rela??o a ligante puro, nos espectros de infravermelho. Este deslocamento tamb?m foi observado nas amostras preparadas com ?cido tereft?lico. As analises de microscopia eletr?nica de varredura sugerem que a morfologia dos p?s e significativamente dependente do tipo de aquecimento usado, convencional ou micro-ondas. / Metal Organic Frameworks (MOFs) are hybrids materials, often crystalline, consisting of metal or metal clusters, connected by polytopic organic ligands repetitively, leading to structures, usually porous. In this work, MOFs based on lanthanide ions (La3+ and Gd3+) and dicarboxylate type of ligands (isophthalic and terephthalic acids), were synthesized by hydrothermal, solvothermal and hydro(solvo)thermal methods. The effects of the synthetic route as well as the type of heating, conventional or by microwave, on the structure and properties of MOFs were studied. The powder samples obtained were characterized by X-ray diffraction, infrared spectroscopy, thermal analysis and scanning electron microscopy. The results suggest that the addition of an organic or inorganic base is needed to promote the deprotonation of the ligand, since in the samples prepared by the hydrothermal method, without the use of a base, no formation of the metalorganic framework was observed. On the other hand, the presence of DMF as solvent or cosolvent, afforded the deprotonation of the ligand with the consequent formation of MOFs. At least two different crystalline structures were identified for the samples prepared with terephthalic acid. These samples are isostructural with those reported for phases Eu(1,3-BDC)DMF, Eu2(1,4-BDC)3 (DMF)2 and Tb(1,4-BDC)H2O. The presence of water in the reaction medium in the hydro(solvo)thermal method, provoked the growth of the structure different from that observed in the absence of water. This can be explained by the difference in the coordination mode of water and DMF to lanthanide ions. Although not identified by XRD, the samples prepared with isophthalic acid, also present metalorganic structures, which was confirmed by the presence of the characteristic displacement of the carbonyl group band in their infrared spectra, compared to the spectrum of the pure ligand. This shift was also observed in the samples prepared with terephthalic acid. Thermal analisys shows that the metal organic frameworks do not collapse occurs at a temperature below 430?C.The analysis of scanning electron microscopy suggests that the morphology of powders is highly dependent on the type of heating used, conventional or by microwave.

Made available in DSpace on 2014-12-17T15:42:25Z (GMT). No. of bitstreams: 1 VivianeOC_DISSERT.pdf: 3402531 bytes, checksum: e2e7a469bf001a9ef16d573773ea7bda (MD5) Previous issue date: 2014-01-24 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Metal Organic Frameworks (MOFs) are supramolecular structures consisted of ions or metal clusters coordinated to organic ligands which are repeated in two or three dimensions. These structures have atracted much attention due to their properties such as low density, high specific surface area and large volume of pores. In this work, MOFs consisted of zinc clusters connected by ditopic ligands, terephthalic acid (1,4- H2BDC) or isophthalic acid (1,3-H2BDC) were synthesized. To obtain the proposed materials, different routes and synthetic parameters were tested, such as the molar ratio of the precursors, the addition of template molecules, the type of solvente, the addition of organic base or the type of a counter-ion of Zn salt. It was found that the variation of these parameters led to the formation of different metalorganic structures. The solids obtained were characterized by XRD, SEM and IR. For the samples identified as MOF- 5, it was verified that the structure was composed of both interpenetrated and non interpenetrated structures. These samples showed a low stability, becoming totally transformed into another structure within less than 72 hours. The addition of the nickel and/or cobalt was found to be a promissing method for increasing the stability of MOF- 5, which in this case, still remained unconverted to another structure even after 15 days of exposure to air. The samples prepared from 1,3-H2BDC were probably new, still unknown Metal Organic Frameworks / Redes Metalorg?nicas (MOFs) s?o estruturas supramoleculares constitu?das de ?ons ou clusters met?licos coordenados com ligantes org?nicos que se repetem em duas (2D) ou tr?s (3D) dimens?es. Essas estruturas t?m atra?do muita aten??o devido ?s suas propriedades, como por exemplo, baixa densidade, elevada ?rea superficial espec?fica e elevado volume de poro livre. Neste trabalho foram sintetizadas MOFs formadas por clusters met?licos de zinco conectados por ligantes dit?picos, ?cido tereft?lico (1,4- H2BDC) ou isoft?lico (1,3-H2BDC). Para a obten??o dos materiais propostos foram testadas diferentes rotas e par?metros de s?ntese, tais como, raz?o molar dos precursores, adi??o de mol?culas de molde, tipo de solvente, adi??o de base org?nica ou do contra-?on do sal de Zn. Constatou-se que a varia??o destes par?metros pode conduzir a forma??o de diferentes estruturas metalorg?nicas. Os s?lidos obtidos foram caracterizados por DRX, MEV e IV e TG. Para as amostras onde foi identificada a rede metalorg?nica MOF-5 verificou-se a exist?ncia de por??es de estrutura interpenetrada, assim como de estrutura n?o interpenetrada. Estas amostras apresentaram baixa estabilidade, convertendo-se totalmente em outra estrutura num per?odo de tempo inferior a 72 h. A adi??o de n?quel e/ou cobalto mostrou-se promissora para o aumento de estabilidade da MOF-5, a qual foi identificada mesmo ap?s 15 dias de exposi??o ao ar. Dentre as amostras preparadas com 1,3-H2BDC apenas uma estrutura foi identificada, com base nos bancos de dados de estruturas conhecidas, levando a crer que tr?s redes metalorg?nicas obtidas apresentam estruturas in?ditas