Síntese, caracterização e estudo fotofísico de complexos de 4,4- diaminoestilbeno-2,2-dissulfonato com íons lantanídeos
This is a work involving fundamental studies of chemistry where the synthesis and structural characterization, as well as a possible future application of these new compounds as luminescent sensors or sunscreen agents, complexes with 4,4 diaminostilbene-2,2-disulfonic (DSD) and trivalent lanthanide...
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Formato: | doctoralThesis |
Idioma: | por |
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Universidade Federal do Rio Grande do Norte
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Endereço do item: | https://repositorio.ufrn.br/jspui/handle/123456789/17788 |
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Resumo: | This is a work involving fundamental studies of chemistry where the synthesis
and structural characterization, as well as a possible future application of these new
compounds as luminescent sensors or sunscreen agents, complexes with 4,4
diaminostilbene-2,2-disulfonic (DSD) and trivalent lanthanide ions La3+, Nd3+, Eu3+,
Gd3+ and Yb3+, were synthesized in the ratio of 3 mmol: 1 mmol (DSD: lanthanides).
The complexes obtained with these ions were present in powder form and were
characterized by complexometric titration with EDTA CHN Elemental analysis,
molecular absorption spectroscopy in the ultraviolet region, the absorption spectroscopy
in the infrared, thermal analysis (TG / DTG), Nuclear Magnetic Resonance - NMR 1H
and Luminescence Spectroscopy. The complexometric titration and CHN analysis,
confirmed the TG / DTG which suggest that these complexes have the following
general chemical formulas:
[La2(C14H12S2O6N2)2(H2O)2Cl2].7H2O,[Nd2(C14H12S2O6N2)2(H2O)2Cl2].6H2O,[Eu2(C14
H12S2O6N2)2(H2O)2Cl2].7H2O,[Gd2(C14H12S2O6N2)2(H2O)2Cl2].4H2O e
[Yb2(C14H12S2O6N2)2(H2O)2].6H2O. The disappearance of the bands in the infrared
spectrum at 2921 cm-1 and 2623 cm-1 and the displacement of the bands in the spectra of
the amine complex indicate that the lanthanide ion is coordinated to the oxygen atoms
and the sulfonate groups of the nitrogens amines, suggesting the formation of the dimer.
The disappearance of the signal and the displacement signal SO3H amines in the 1H
NMR spectrum of this complex are also indicative coordination and dimer formation.
The Thermogravimetry indicates that the DSD is thermally stable in the range of 40º to
385°C and their complexes with lanthanide ions exhibit weight loss between 4 and 5
stages. The Uv-visible spectra indicated that the DSD and complexes exhibit cis
isomers. The analysis of luminescence indicates that the complexes do not exhibit
emission in the region of the lanthanides but an intense emission part of the binder. This
is related to the triplet states of the ligand, which are in the lowest energy state emitting
lanthanide ions, and also the formation of the dimer that suppress the luminescence of
ion Eu3+. The formation of dimer was also confirmed by calculating the europium
complex structure using the model Hamiltonian PM6 and Sparkle |
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