Synthesis, Crystal Structure, and Thermal Decomposition Kinetics of the Complex of Ho 2,4-Dichlorobenzoic Acid and 2,2′-Bipyridine

Abstract

The complex [Ho(2,4-DClBA)3bipy]2 (2,4-DClBA = 2,4-dichlorobenzoate; bipy = 2,2′-bipyridine) was synthesized and characterized by elemental analysis, infrared spectra, ultraviolet spectra, single-crystal X-ray diffraction, thermogravimetry, and differential thermogravimetry (TG-DTG) techniques. The crystal is monoclinic with space group P2(1)/n. The coordination number of the Ho3+ ion is nine. Two Ho3+ ions are connected via two bidentate bridging and two bidentate chelating−bridging modes. The thermal decomposition behavior of the title complex under a nitrogenous atmosphere was studied using the TG-DTG and IR techniques. The nonisothermal kinetics was investigated by using the Popescu method and the integral isoconversional nonlinear method (NL-INT). The mechanism function of the first decomposition step was determined. The thermodynamic parameters (ΔG⧧, ΔH⧧, and ΔS⧧) were also calculated, and kinetic parameters (activation energy E and the pre-exponential factor A) were also obtained.