Synthesis, crystal structure and thermal decomposition kinetics of the complex [Sm(BA) 3bipy] 2

Abstract

The complex of [Sm(BA) 3bipy] 2 (BA = benzoic acid; bipy = 2,2′-bipyridine) was obtained and characterized by elemental analysis, molar conductance, IR spectra, UV spectra, single crystal X-ray diffraction and TG–DTG techniques. The crystal is monoclinic with space group P2(1)/ n. The unit cell parameters are: a = 14.157(2) Å, b = 15.416(3) Å, c = 26.079(4) Å, β = 103.445(2)°. Two Sm 3+ ions are connected by four carboxylic groups through bridging bidentate mode. Each center Sm 3+ is eight-coordinated with a trigondodecahedron. The thermal decomposition behaviors of the title complex in a static air atmosphere were discussed by TG–DTG and IR techniques. The non-isothermal kinetics was investigated by using double equal-double step method and nonlinear integral isoconversional method. The mechanism function of the first decomposition step was determined. Meanwhile, the thermodynamic parameters (Δ H ≠, Δ G ≠ and Δ S ≠) and kinetic parameters (activation energy E and pre-exponential factor A) were also calculated. The lifetime equation at mass-loss of 10% was deduced as ln τ = −34.56 + 19299.15/ T by isothermal thermogravimetric analysis. The title complex can be used in many areas such as extraction, separation, germicide, catalysis and functional materials and so on.