Ressonância paramagnética eletrônica no estudo de estruturas porfirínicas

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

03/08/2009

RESUMO

Corboxyphenylporphyrins metal: TcPPM, M = H2, Fe, Co, Ni, Cu e Zn, free and anchored on TiO2 was synthesized and characterized by EPR spectroscopy. The EPR spectra were measured in X- (9 GHz), Q- (34 GHz) and W bands (94 GHz), at room temperature as well at 77 K. The TcPPH2, TcPPCo, TcPPNi and TcPPZn RPE spectra showed only one line which is due to free radicals, while in the TcPPM anchored on TiO2 (TcPPM/TiO2) the signal showed lower intensity than the free porphyrins (about of 300 times less intense) , which is in agreement with the molecule number esteem in the free and anchored porphyrins. The EPR spectra of TcPPCu and TcPPFe exhibited resolved lines of Cu and Fe species respectively, besides Mn2+ species was detected in TcPPFe as impurities. For TcPPCu spectroscopic parameters were accurately determined: g//=2,186 and g┴=2,049 and A// =178 Gauss e A┴=8 Gauss and A’Cu-N~16 Gauss. The RPE spectra have indicated that the bonding between the carboxyl functional group in the meso position of the porphyrins and TiO2 did not have influence on the radical free signal.

ASSUNTO(S)

ressonância paramagnética eletrônica porfirina e compostos de porfirina porphyrins electron spin resonance

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