Moura, Maria de Fátima Vitória deCarvalho, Genickson Borges de2017-03-102017-03-102016-07-29CARVALHO, Genickson Borges de. Síntese, caracterização e investigação da fotoluminescência de complexos da pirazinacarboxamida com íons lantânio e lantanídeos. 2016. 233f. Tese (Doutorado em Química) - Centro de Ciências Exatas e da Terra, Universidade Federal do Rio Grande do Norte, Natal, 2016.https://repositorio.ufrn.br/jspui/handle/123456789/22210This present work describes the synthesis and characterization of coordination compounds between lanthanide nitrate (III) and pyrazinecarboxamide (PyZ), intending a possible functional application of these new compounds as molecular light conversion devices. The obtained compounds were characterized by various analytical techniques, of which we highlight: elemental analysis, molar electrolytic conductivity, thermogravimetry (TG) and differential thermal analysis (DTA) simultaneous, differential scanning calorimetry (DSC), absorption spectroscopy in mid infrared (FT-IR) spectroscopy by energy dispersive Xray (EDS), diffraction X-ray (XRD) by the powder method spectroscopy electronic absorption (UV-Vis) at 298 K and luminescence spectroscopy at 298 K. From the results of elemental analysis, thermogravimetry and molar electrolytic conductivity, it was possible to propose the following molecular formulas: [Ln(PyZ)2(NO3)2]NO3.2H2O (Ln3+ = La-Eu) and [Ln(PyZ)2 (NO3)2]NO3.H2O (Ln3+ = Gd-Dy). The TG-DTA and DSC curves provided information about dehydration, degradation, stability and nature of thermal events related to decomposition processes. The conductivity data, both nitromethane and acetonitrile, suggested an electrolyte behavior 1:1 for all compounds, reinforcing the results of the absorption spectra in the middle infrared region, which indicated the presence of nitrate is not coordinated to the metal ions. Regarding the electronic spectra UV-Vis, it was observed displacement of the absorption bands of the studied complexes, when compared to the free ligand bands, suggesting the coordination of the central metal ion with the binder pyrazinecarboxamide. The analysis of absorption spectra in the infrared (FT-IR) leads to stabilish that sites of coordination with the PyZ binder metal ion are carbonyl oxygen and nitrogen α pyrazine ring. The interpretation of X-ray diffraction revealed the existence of three isomorphic series: the first comprises those compounds of La3+ and Ce3+, the second compounds of the Pr3+, Tb3+ and Dy3+ to the third compound. The study of hipersensitivas bands of neodymium complex in the solid state at 298 K allowed the determination of spectroscopic parameters, numerical values which indicate that metal-ligand interaction is essentially electrostatic. The oscillator strength (P) was calculated from the electronic spectra in acetonitrile solution and ethanol. The P values suggest a greater influence of ethanol in coordination ion Nd3+ ball. The emission spectrum of the gadolinium complex showed that the energy of the excited triplet state PyZ binder is between the emitting level of the Tb ions and I, which favors the process of metal-ligand energy transfer. Based on the analysis of the europium compound emission spectrum in the solid state at 298 K, it was possible to assign a microssimetria approximately D2d, consistent with the geometry of a distorted dodecahedron for the compound. Luminescence analysis suggests that the complexes of Eu3+, Tb3+, Sm3+ and Dy3+ display characteristic emissions in the region of lanthanide ions, however, when in acetonitrile solution, only samarium complex showed no emission in the visible region, probaly because a suppression of luminescence by the presence of the solvent.Acesso AbertoComplexosLuminescênciaPirazinacarboxamidaLantanídeosdoctoralThesisCNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA