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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Síntese e investigações estruturais de arranjos supramoleculares formados por metaloporfirinas e metaloftalocianinas / Syntheses and structural investigations of supramolecular arrays formed by metalloporphyrins and metallophthalocyanines.

Melo, Cristiane Cabral de 29 June 2012 (has links)
Made available in DSpace on 2016-06-02T20:34:37Z (GMT). No. of bitstreams: 1 4600.pdf: 3262099 bytes, checksum: 1b7e10bcd82d9c791f13376725a1f80f (MD5) Previous issue date: 2012-06-29 / Universidade Federal de Minas Gerais / This thesis involves the syntheses and characterization of four heterotriads formed by metallotetraphenylporphyrins (CoTPP and NiTPP) and metallophthalocyanines (CoPc and NiPc) using pyrazine (pz) and trans-1,2-bis(4-pyridyl)ethylene (bpe) as spacer ligands. The following sequences: NiPc(pz)CoTPP(pz)NiPc, NiTPP(pz)CoPc(pz)NiTPP, NiTPP(bpe)CoPc(bpe)NiTPP and CoTPP(bpe)CoPc(bpe)CoTPP were investigated. All triads were analyzed by infrared and ultraviolet-visible spectroscopy and some of them were characterized by elemental analysis, termogravimetry and differential thermal analysis. The infrared and electronic spectra of the triads showed characteristic absorption bands of the two macrocycles. The elemental data are in a good agreement with the proposed stoichiometry of these arrays. The triad NiTPP(pz)CoPc(pz)NiTPP had its stoichiometry confirmed via thermogravimetry and elemental analysis. Besides these results, this thesis also reports the crystal structure of a new pseudopolymorph of cobalt tetraphenylporphyrin (CoTPP) obtained by single-crystal X-ray diffraction. This non-stoichiometric solvate crystallized in the space group Pī with unit cell parameters distinct from the non-solvated CoTPP, which in general, like others metallotetraphenylporphyrins, tends to crystallize in the tetragonal space group I42d. The triclinic and tetragonal forms differ with respect to the conformation adopted by the macrocycle and also in the phenyl orientation. Crystal packing analysis of this pseudopolymorph revealed the presence of infinite channels along the a axis that are filled by dichloromethane solvent molecules, which represents therefore the first clathrate of CoTPP reported in the literature. / Essa tese envolve a síntese e a caracterização de quatro heterotríades constituídas por metalotetrafenilporfirinas (CoTPP e NiTPP) e metaloftalocianinas (CoPc e NiPc) usando pirazina (pz) e trans-1,2-bis(4-piridil)etileno (bpe) como ligantes espaçadores. As seguintes sequências foram investigadas: NiPc(pz)CoTPP(pz)NiPc, NiTPP(pz)CoPc(pz)NiTPP, NiTPP(bpe)CoPc(bpe)NiTPP e CoTPP(bpe)CoPc(bpe)CoTPP. Todas as tríades foram caracterizadas por espectroscopia no infravermelho e no ultravioleta-visível. Algumas delas foram analisadas por termogravimetria, análise térmica diferencial e análise elementar. Os espectros no ultravioleta-visível e no infravermelho das tríades mostraram bandas de absorção características dos dois macrociclos. Os dados da análise elementar exibiram uma boa correlação com a estequiometria proposta para esses arranjos. A tríade NiTPP(pz)CoPc(pz)NiTPP teve a sua estequiometria confirmada por análise elementar e termogravimétrica. Além desses resultados, essa tese também reporta a estrutura cristalográfica de um novo pseudopolimorfo da cobaltotetrafenilporfirina (CoTPP) obtido por difração de raios X por monocristal. Esse solvato não estequiométrico cristalizou no grupo espacial Pī com parâmetros de cela distintos da forma não solvatada da CoTPP, a qual em geral, assim como outras metalotetrafenilporfirinas, tendem a cristalizar no grupo espacial tetragonal I42d. Além das diferenças conformacionais adotadas pelo macrociclo, as formas triclínica e tetragonal da CoTPP também diferem em relação a orientação das fenilas. A análise do empacotamento cristalino desse pseudopolimorfo revelou a formação de infinitos canais paralelos ao eixo a, preenchidos por moléculas do solvente diclorometano, constituindo o primeiro clatrato de CoTPP reportado na literatura.

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