Synthesis, crystal structures, and thermodynamic properties of two new lanthanide complexes

Two new complexes [Tb(2,3-DClBA)(3)(5,5'-dmebipy)(H2O)](2) and [Er(2,3-DClBA)(3)(5,5'-dmebipy)(H2O)](2) (2,3-DClBA = 2,3-dichlorobenzoate; 5,5'-dmebipy = 5,5'-dimethylbipyridine) were prepared and characterized by single crystal X-ray diffraction, elemental analysis, IR spectra, and TG/DSC technology. Single crystal X-ray diffraction data show that the two complexes are isomorphous. The complex is a binuclear molecular. Each Ln(3+) center is coordinated by six oxygen atoms and two nitrogen atoms to form a distorted square antiprism geometry. The supramolecular architecture of the complex is constructed by H bond and halogen-halogen interactions. The thermal decomposition mechanism of the two complexes has been studied by TG/DSC technology. The low-temperature heat capacities of the complexes have been measured using a physical property measurement system in the temperature range from 10 to 302 K. The heat capacities were fitted to the polynomial equations by a least square method, and the thermodynamic functions were calculated based on the curve fitting.