稀土-天冬氨酸-咪唑配合物Sm_2(Asp)_2(Im)_6(ClO_4)_6·6H_2O的特殊低温相变和热力学性质  

Special Phase Transition under Low Temperature and Thermodynamic Properties of Rare Earth Complex Sm_2(Asp)_2(Im)_6(ClO_4)_6·6H_2O

作　　者：王凯[1] 高肖汉[1] 吕雪川[1] 谭志诚[2] 曹慧[1] 

机构地区：[1]辽宁石油化工大学化学化工与环境学部化学与材料科学学院,抚顺113001 [2]中国科学院大连化学物理研究所热化学实验室,大连116023

出　　处：《化学通报》2016年第2期141-146,共6页Chemistry

基　　金：国家自然科学青年基金项目(21103078;21003069)资助

摘　　要：合成了标题配合物,测定了其晶体在80 ～ 385 K温度范围的等压摩尔热容,低温区间的绝热量热和差示扫描量热均发现配合物在220K和245K附近存在固-固相转变,推测其机理可能是配合物中高氯酸根的重取向运动不同阶段所造成;根据实验热容数据和热力学公式,计算出配合物在80～385 K温度区域内相对于298.15K的标准热力学函数[HT-H298.15]和[ST-S298.15],根据热容测定数据计算出该相变的焓变和熵变.用热重法检测了配合物的热稳定性并推测其热分解机理.这两个低温区相变过程的发现,使开发此类配合物作为新低温相变材料成为可能.A ternary complex of rare earth ion, Sm2 （Asp） 2 （Ira） 6 （ ClO4 ） 6 · 6H2O, was synthesized and its thermodynamic properties were studied. Molar heat capacities at constant pressure （ Cp.m ） of the complex were measured with a high-precision automatic adiabatic calorimeter over the temperature range from 80 to 390 K, and the thermodynamic functions （H T-H298.15 and S T-S298.15 ） were derived from the heat capacity data with temperature interval of 5 K. The phase transitions of the new complex around 220 K and 245 K were discovered both by adiabatic calorimetry and differential scanning calorimetry （ DSC ）. The thermodynamic data of the phase transitions were calculated and the mechanism of phase transitions was deduced to be the reorientation process of perchlorate ions in the complex. Thermal stability of the complex was tested by thermogravimetric （TG） technique and a possible mechanism for the decomposition was suggested.

关 键 词：稀土配合物 固-固相转变 热稳定性 绝热量热法 热容 热力学函数 

分 类 号：O641.4[理学—物理化学]