TITLE:
Syntheses and Co-Fluorescence of Complexes of Eu (III)/Gd (III) with Thienyltrifluoroacetonate, Terephthalic Acid and Phenanthroline
AUTHORS:
Xuehui Zhao, Zhongliang Hu, Haiyun Jiang, Feipeng Jiao, Zhengxiang Wang
KEYWORDS:
Co-Fluorescence, Europium, Terephthalic Acid, 2-Thienyltrifluoroacetonate, Silica Gel
JOURNAL NAME:
American Journal of Analytical Chemistry,
Vol.5 No.17,
December
29,
2014
ABSTRACT: A
series of complexes of europium (III)/gadolinium (III) with 2-thienyltrifluoroacetonate
(HTTA), terephthalic acid (TPA) and phenanthroline (Phen) were synthesized by
coprecipitation. The resulting complexes including Eu2(TPA)(TTA)4Phen2,
Eu1.4Gd0.6(TPA)(TTA)4Phen2, Eu1.0Gd1.0(TPA)(TTA)4Phen2 and Eu0.8Gd1.2(TPA)(TTA)4Phen2 were characterized by elemental analysis, IR spectroscopy and thermal stability analysis. The results of analysis indicate that the complexes obtained have similar binuclear structure with each other. The thermal stability analysis
indicates that the complexes Eu2(TPA)(TTA)4Phen2and
Eu1.0Gd1.0(TPA)(TTA)4Phen2 possess
good thermal stability, which melt at ~241°C and decompose at ~370°C - 430°C corresponding
to the formation of the complexes. The fluorescence spectra of Eu2(1-x)Gd2x(TPA)(TTA)4Phen2 (x = 0 - 1) complex powders and their doped silica gels were studied. The co-fluorescence effect of Gd3+ ions in complex powders is different from that of
their doped silica gels. The optimum concentration of Gd3+ for
complex powders and their doped silica gels is 0.5 and 0.3 (molar fraction), respectively.
The co-fluorescence distinction of Gd3+ ions for complex powders and
their doped silica gels is preferably
interpreted from the proposed binuclear structure together with monomolecular
compositions of the complexes for the first time. Both intermolecular
energy transfer and intra molecular energy transfer in cross binuclear monomolecular
EuGd(TPA)(TTA)4Phen2 are thought to be responsible for
the co-fluorescence effect of the complex powders; yet only the latter is
thought to be responsible for the co-fluorescence effect in silica gels, for
the complex molecules in this case are isolated from each other.