Synthesis, Crystal Structure, and Thermal Decomposition Kinetics of the Complex of Dysprosium Benzoate with 2,2 '-Bipyridine

The complex [Dy(BA)(3)bipy](2) (BA = benzoate; bipy = 2,2'-bipyridine) was obtained and characterized by elemental analysis, molar conductance, infrared spectra (IR), ultraviolet spectra (UV), single-crystal X-ray diffraction, thermogravimetry, and differential thermogravimetry (TG-DTG) techniques. The crystal is monoclinic with space group P2(1)/n. The unit cell parameters are: a = 14.1114(8) angstrom, b = 15.3743(9) angstrom, c = 25.8887(14) angstrom, a = 90 degrees, beta = 103.4410(10)degrees, y = 90 degrees. Two Dy3+ ions are connected by four carboxylic groups through a bridging bidentate mode. The thermal decomposition behavior of the title complex under a static air atmosphere was studied using the TG-DTG, scanning electron microscopy (SEM), and IR techniques. The nonisothermal kinetics was investigated by using the double equal-double steps method and the Starink method. The mechanism function of the first decomposition step was determined. The thermodynamic parameters (Delta H-not equal, Delta G(not equal), and Delta S-not equal) and kinetic parameters (activation energy E and the pre-exponential factor A) were also calculated.