2-氯-6-氟苯甲酸钆配合物的晶体结构及热分解反应动力学和热力学研究

Crystal Structure,Thermal Decomposition Kinetics and Thermodynamic Properties of Gadolinium Complex with 2-chloro-6-fluorobenzoicacid

采用超声法合成了钆的三元配合物[Gd(2-Cl-6-FBA)_(3)(4-OH-terpy)(CH_(3)CH_(2)O)]·0.75CH_(3)CH_(2)OH(BA=苯甲酸,terpy=2,2′:6′,2″-三联吡啶).通过元素分析、红外光谱(IR)、拉曼光谱(R)、单晶X射线衍射(SXRD)以及X射线粉末衍射(PXRD)等手段对配合物进行了表征.晶体结构分析表明,该配合物为单核分子,属于单斜晶系,P2_(1)/c空间群,中心金属离子配位数为9.研究了配合物在不同升温速率下的热分解反应机理,并采用非线性等转化率积分(NL-INT)法和迭代Ozawa法分别求得了配合物在第1步热分解过程中的活化能,2者结果基本一致.采用差示扫描量热(DSC)技术测定了配合物的摩尔热容,利用最小二乘法将平均摩尔热容与折合温度进行拟合得到多项式方程,通过多项式方程和热力学方程计算得到配合物的舒平摩尔热容和热力学函数值.

A ternary gadolinium complex,[Gd(2-Cl-6-FBA)_(3)(4-OH-terpy)(CH_(3)CH_(2)O)]·0.75CH_(3)CH_(2)OH(BA=benzoicacid,terpy=2,2′:6′,2″-terpyridine) was synthesized by ultrasonic method.The complex was characterized by elemental analysis,Infrared spectroscopy(IR),Raman spectroscopy(R),single crystal X-ray diffraction(SXRD) and X-ray powder diffraction(PXRD).The crystal structure analysis showed that the complex consisted of a single nuclear molecule,belonging to monoclinic crystal system,P2_(1)/c space group.The coordination number of the central metal ion was 9.The thermal decomposition reaction mechanisms of the complex under different heating rates were studied,and the activation energy of the complex in the first step of thermal decomposition was calculated by integral iso-conversional nonlinear(NL-INT) method and iterative Ozawa method.The molar heat capacity of the complex was measured by a DSC instrument,and the polynomial equation was obtained by fitting the average molar heat capacity to the equivalent temperature by the least square method.And then the smoothed molar heat capacity and thermodynamic functions of the complex were calculated by polynomial equation and thermodynamic equation,respectively.