论文部分内容阅读
Some binuclear lanthanide complexes with the general formula [Ln(2,3-DClBA)3bipy]2 (Ln = Sm(l), Eu(2), Tb(3), Dy(4) and Ho(5); 2,3-DClBA=2,3-dichlorobenzoate; bipy = 2,2-bipyridine) were synthesized and characterized by elemental analysis, molar conductance, infrared, ultraviolet, luminescent spectroscopy, thermogravimetry and different thermogravimetry (TG-DTG) techniques. The single crystals of the complexes have been obtained except the complex 2 and their structures have been determined by single-crystal X-ray diffraction. The four complexes are iso-structural and the rare earth ions are all nine coordinated. The two rare earth ions in each complex are linked by two bridging bidentate and two chelating-bridging tridentate carboxylate groups. Under ultraviolet light excitation, the europium and terbium complexes exhibited characteristic red fluorescence of Eu3+ ion and green fluorescence of Tb3+ ion at room temperature. The non-isothermal kinetics was investigated by using the integral isoconversional non-linear (NL-INT) and the Popescu methods. The mechanism functions of the first decomposition step of the complexes 3-5 were determined. Meanwhile, the thermodynamic parameters (△G≠, △H≠ and △S≠) at DTG peak temperatures were also calculated.