Luminescence properties of the co-luminescence groups of Sm-La-pyridyl carboxylic acids

A novel ligand, N,N＇-（2,6-pyridinedicarbonyl）bis[N-（carboxymethyl）] （Lj） was designed and synthesized starting from pyri- dine-2,6-dicarboxylic acid （I）. The ligand （L0 and ititermediate product （3） were characterized by 1H nuclear magnetic resonance （NMR）, Fourier transform infrared spectrometer （FT-IR） spectra and elemental analysis. Besides, four novel co-luminescence systems of Sm-La-pyridyl carboxylic acids： K4Sm（1-x）Lax（L1）C13T1H20, K12Sm2（1-x）La2x（L2）3 C16y2H2O, K6Sm20 xyLa2x（L3）C16-y3H：O and K4Sm（1-x）Lax（L4）Cl3y4H20 （x was the mole fraction of La（III） in the mixed ions, the value was 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, respectively; Yl, Y2, Y3, Y4 were plus integer） were studied, and the mechanism of fluorescence enhancement effect was discussed detailedly.