Síntese e caracterização de compostos de ferro com ligantes heterocíclicos nitrogenados

• Autor(a) principal: Vilela Filho, Nilton Caetano
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFMT
• Texto Completo: http://ri.ufmt.br/handle/1/1457
• topic: .; CNPQ::CIENCIAS EXATAS E DA TERRA; .

In this present work, the route of synthesis and characterization of Fe (II) compounds coordinated ligands N-heterocyclic (pyridine, isonicotinamide, phenanthroline) with the possibility of application as sensitizing dyes in solar cells of the type (DSSC). The compounds were characterized by IR and UV-Vis spectroscopy, elemental analysis, thermal analysis and X-ray diffraction and, in general, the UV-visible spectra obtained for the three complexes revealed the presence of Load Transfer Ligand Metal bands (MLCT) in 418 nm (isn complex), 420 nm (py complex) and 422 nm (phen complex) corresponding to the interaction among the ligands and the transition metal Fe (II). Is also observed a number of bands between 200 and 300 nm that can be attributed to internal transition of the ligands (→*),to pyridine, isonicotinamide, phenanthroline and cyanide. The structural characterization performed by spectroscopy in the mid-infrared region shows a decrease in the peak cyanide 2250 cm-1, assigned to the symmetric vibration of the cyanide group νs(CN). For the spectrum obtained with pyridine complex is observed characteristic peaks of pyridine ligand in 1400 -1600 cm-1, attributed to symmetric and asymmetric vibrations of the group (C=C). Furthermore also shows a corresponding peak symmetric vibration of the group CH (pyridine ring at 3075 cm-1). To the obtained compound with the ligand isonicotinamide, characteristic bands are observed (C=O), in the range of 1680 cm-1, NH2 bands in the range 3475-3150 cm-1, as well as the CN bands presence in 2250 cm-1. The characteristic symmetric and asymmetric vibrational modes of the phenanthroline ligand were also observed in the groups as (C=C) 1106 - 1707 cm-1, (C=H) 3062 cm-1 symmetric vibration, (C=N) at 726 cm-1 of angular deformation of the pyridine ring. Similarly to the other complex, it is also possible to realize in the spectrum of this compound the presence of symmetric vibration of the CN group in 2250 cm-1. Elemental analysis allowed to determine the stoichiometry of the K3[Fe(CN)5(py)].4KCN and K3[Fe(CN)5(isn)] compounds, although it was not possible to determine the molecular formula of the synthesized complex with the ligand phen. Through thermal analysis identified the oxidation state of the metal center in compounds which have been formed. The future prospects, with regard to this study are to produce important information for the development of alternative compounds of power generation to assist the already installed, thus decreasing the risk of a collapse in the supply system.