【作者】 王晓玲；

【导师】 高胜利； 陈三平；

【作者基本信息】 西北大学 ， 无机化学， 2010， 博士

【摘要】 基于电子结构的规律性,稀土配合物的结构随原子序数的变化呈现相应的规律性；稀土配合物的热力学性质随原子序数的增加同样呈现了规律性的变化。进行物质的热力学性质研究,通过其与结构的有效关联,是实现该类配合物定向调控和制备的基础。本文选择5-硝基间苯二甲酸作为有机配体与稀土金属离子作用,系统地探索了稀土配合物晶体结构和热力学性质的规律性及其关联。主要研究内容及结论如下：(1)以5-硝基间苯二甲酸为配体,在水溶液中制备了系列稀土配合物(1)-(15)。通过单晶衍射、化学分析、元素分析、红外等手段对配合物进行了表征。确定了它们的结构并对其结构、配位模式进行了比较。结构分析表明,15个配合物中,配合物[RE4(5-NO2-bdc)6(H2O)10]·7H2O (RE=La, Ce)为同构化合物；配合物[RE3(5-NO2bdc)4(5-NO2-Hbdc)(H2O)7]·nH2O(RE=Pr,Nd,Sm,Eu)为同构化合物；配合物[RE2(5-NO2-bdc)3(H2O)5]·5H20 (RE=Gd,Tb)为同构化合物；配合物[RE2(5-NO2-Hbdc)2(5-NO2bdc)2(H2O)8]·4H2O(RE=Dy,Ho,Y)为同构化合物；配合物[RE2(5-NO2-bdc)4(H2O)6][RE2(5-NO2-bdc)2(H2O)8]·nH2O(RE=Er,Tm,Yb,Lu)为同构化合物,显示“五分组”效应。(2)用微量热法测量了稀土硝酸盐的溶解焓,5-硝基间苯二甲酸与稀土离子的液相反应焓变；针对反应过程设计了合理的热化学循环,并根据热化学循环计算了系列配合物固相生成反应焓变及配合物的标准摩尔生成焓。分别以配合物液相、固相反应焓变与镧系元素原子系数作图,配合物的标准摩尔生成焓与镧系元素原子系数作图,呈现“五分组”效应。分组结果与上述配合物晶体结构的分组现象相一致。钇配合物属第四组,与镝配合物和钬配合物同组。(3)通过全自动精密自动绝热量热计测得稀土配合物在78～380 K温区的低温摩尔热容,对热容数据进行了处理和归纳。从每种配合物的热容曲线可知,它们在78～380 K温区没有任何熔解、分解、缔合等热异常现象发生,配合物在此温区内稳定。将配合物的低温热容数据对折合温度进行拟合,得到了各配合物摩尔热容对温度的多项式方程。利用此多项式方程进行数值积分,得到了配合物每隔5 K的舒平热容值和各种热力学函数值。以298.15 K温度下的热容、300 K时的两种热力学函数(HT-H298.15 K)和(ST-S298.15 K)对镧系元素原子序数作图,均呈现“五分组”效应。分组结果与上述配合物晶体结构的分组现象相一致。钇配合物属第四组,与镝配合物和钬配合物同组。更多还原

【Abstract】 The structures of lanthanide carboxylate complexes exhibit good regularity with increasing atomic number based on the electron configuration of lanthanides, while the thermodynamic properties of the complexes also present a regular change with increasing atomic number. It is of signifance for oriental regulating and preparation of the complex to explore the investigation of the thermodynamics and summarize the relationship of the thermodynamics with the structures for the complexes. In this dissertation,5-nitroisophthalic acid was selected as the ligand to interact with lanthanide ions. The regularity of crystal structures and thermodynamics of the lanthanide coordination polymers and their relationship were investigated. The contents and conclusion were described as follows:(1) A series of lanthanide coordination polymers (1)～(15) were synthesized by reaction of 5-nitroisophthalic acid with lanthanide ions in aqueous solution and characterized by X-ray single crystal diffraction, chemical analysis, element analysis, and infrared spectrum. Their structures were determined and the coordination modes were compared. The results showed that the complexes could be divided into five groups according to the structure and composition: [RE4(5-N02-bdc)6(H20)10]·7H20 (RE=La, Ce); [RE3(5-NO2bdc)4(5-NO2-Hbdc)(H2O)7]·nH2O (RE=Pr, Nd, Sm, Eu); [RE2(5-NO2-bdc)3(H2O)5]·5H2O (RE=Gd, Tb); [RE2(5-NO2-Hbdc)2 (5-NO2bdc)2(H2O)8]-4H2O (RE=Dy, Ho, Y) and [RE(5-NO2-bdc)4(H2O)6][RE2(5-NO2-bdc)2 (H2O)8]·nH2O (RE=Er, Tm, Yb, Lu). The complexes in the same series are isomorphism with quintuple effect.(2) The enthalpy of solution for the lanthanides nitrate hydrate and the enthalpy changes of the liquid phase formation reaction for the complexes were measured by a microcalorimetry. A series of rational thermochemical cycles were designed for the reaction process. The enthalpy changes of formation reactions of the solid complexes, as well as the standard molar enthalpy, were calculated through the thermochemical cycles. The plots of the enthalpy changes, the standard molar enthalpy of the liquid and solid phase for formation complexes against the lanthanide atomic numbers revealed quintuple effect, which was consistent with that of the crystal structure of the series complexes. The yttrium complex was attributed to the fourth group, which is same as dysprosium and holmium complexes.(3) Low-temperature heat capacities of the complexes were determined by a precision automated adiabatic calorimeter from 78 to 398 K. The heat capacity curves showed that no any changes, such as phase change, association, and thermal decomposition occurred during measurement. This result revealed that the compound is stable from 78 K to 398 K. Having Fitted the experimental points by means of the least-squares method, a polynomial equation of the experimental molar heat capacities (Cp,m) versus reduced temperature could be obtained. The smoothed molar heat capacities of the complexes and the thermodynamic functions with 5K temperature intervals were calculated by the fitted polynomial equation. The plots of the experimental molar heat capacities (Cp,m) at 298.15 K, the data of thermodynamic functions (HT-H298.15k) and (ST-S398.15k) at 300K, against the lanthanide atom numbers exhibited quintuple effect, which is consistent with that of the crystal structure of the series complexes. The yttrium complex attributed to the forth group, which is same as dysprosium and holmium complexes.更多还原