[Study on the synthesis, characterization of structure and fluorescence properties of the solid complex of europium ion with 1,10-phenanthroline and 2-thiopheneglyoxylic acid].

The complex of europium with 1,10-phenanthroline and 2-thiopheneglyoxylic acid (HL) was synthesized. Its chemical formula was determined to be [EuL2 x phen x (H2O)3]NO3 by elemental analysis, electrical conductivity, IR and 1H NMR. It was found that the europium ion coordinated to the O atoms of 2-thiopheneglyoxylic acid and H2O, and to the N atoms of 1,10-phenanthroline. Its fluorescence property was determined by the excitation and emission spectra at room temperature, the emission peaks at 592 and 618 nm were assigned to the 5D0-7F1 and 5D0-7F2, respectively. It was also observed that the title complex emits strong red fluorescence under ultraviolet light at room temperature. In the IR spectrum, the characteristic absorption nu(C=O) (1719 cm(-1)), nu(C-O) (1232 cm(-1)), delta(O-H) (909 cm(-1)) of 2-thiopheneglyoxylic acid disappeared in the complex, the nu(as) and nu(s) of -COO- appeared at 1642 and 1408 cm(-1) in the complex respectively. In 1H NMR, the signals of 2-thiopheneglyoxylic acid were shifted upfield, and those of 1,10-phenanthroline downfield. It is proved by the TG curve that the complex is stable from ambient temperature to 250 degrees C.