新型三元配合物[RE(C_7H_5O_3)_2(C_6H_4NO_2)·H_2O](RE=La,Ce,Nd)的合成、光谱特性和热化学性质  

Synthesis, spectral and thermochemical properties of three novel ternary complexes [RE(C_7H_5O_3)_2(C_6H_4NO_2)·H_2O](RE=La,Ce,Nd)

作　　者：肖圣雄[1,2] 蒋建宏[1,2] 李旭[1,2] 郑小芳[2] 熊维维[2] 李传华[1,2] 叶丽娟[1,2] 李强国[1,2] 

机构地区：[1]湘南稀贵金属化合物及其应用湖南省重点实验室,郴州423043 [2]湘南学院化学与生命科学系,郴州423043

出　　处：《中国科学：化学》2014年第6期1058-1066,共9页SCIENTIA SINICA Chimica

基　　金：国家自然科学基金(21273190);湖南省科技计划项目(2012TP4021-6);"湘南稀贵金属配合物及其应用"湖南省重点实验室开放课题重点项目(2012XGJSZD03);"应用化学"湖南省重点学科;湖南省普通高校"十二五"专业综合改革试点项目(湘教通[2012]266号);湖南省普通高校实践教学建设项目(湘教通[2013]295号)资助

摘　　要：采用均匀沉淀法,在20%的乙醇水溶液中,用水杨酸、维生素B3与稀土硝酸盐合成了一类新的稀土三元配合物.通过元素分析、化学分析、摩尔电导、红外光谱、紫外光谱、热重-微分热重分析等手段对配合物的结构和性质进行表征,确定了它们的组成通式为[RE(C7H5O3)2(C6H4NO2)·H2O](RE=La,Ce,Nd).维生素B3吡啶环上的N原子和水杨酸的酚羟基均未参与配位,两种配体均是脱质子后以羧酸根与RE3+离子配位,且成键以离子性为主,兼有部分共价性.在298.15 K,用精密的溶解-反应热量计分别测量了配位反应相关各物质的溶解焓,根据盖斯(Hess)定律求得合成反应的标准摩尔反应焓r mHФ分别为:(180.61±0.72)、(187.25±0.68)和(185.61±0.26)kJ/mol.进而求出配合物的标准摩尔生成焓为:f mHФ[La(C7H5O3)2(C6H4NO2)·H2O(s),298.15 K]=-(2493.9±2.9)、f mHФ[Ce(C7H5O3)2(C6H4NO2)·H2O(s),298.15 K]=-(2441.0±2.8)和f mHФ[Nd(C7H5O3)2(C6H4NO2)·H2O(s),298.15 K]=-(2463.1±2.9)kJ/mol.A new class of ternary rare earth complexes, [RE（C7H5O3）2（C6H4NO2）·H2O] （RE = La, Ce, Nd）, were synthesized from salicylic acid, vitamin B3 with rare earth nitrate by homogeneous precipitation method in a 20% aqueous ethanol. Their compositions and structures were characterized by elemental analysis, chemical analysis, molar conductance, UV spectra, IR spectra and thermogravimetric analysis. Two ligands of C6H5NO2 and C7H6O3 were bidentate-coordinated with RE3＋ ion by removing the proton from the hydroxyl group, the coordination of rare earth was priority to the ionic bond, both part of covalency. The nitrogen atom of pyridine ring and the phenolic hydroxyl oxygen were not involved in coordination. At a constant temperature of 298.15 K, the dissolution enthalpies of the reactants and products of the RE3＋ coordination reactions in the optimal calorimetric solvent were determined by an advanced solution-reaction isoperibol microcalorimeter. According to Hess＇s law, the thermochemical cycle was designed and the standard molar enthalpies of reaction of the RE3＋ complexes were determined to be： （180.61 ± 0.72）, （187.25 ± 0.68）, （185.54 ± 0.76） kJ/mol. And then, the standard molar enthalpies of formation of the RE3＋ complexes were calculated to be： ΔfHmθ[La（C7H5O3）2（C6H4NO2）·H2O（s）, 298.15 K] = -（2493.9 ± 2.9）, ΔfHmθ[Ce（C7H5O3）2（C6H4NO2）·H2O（s）, 298.15 K] = -（2441.0 ± 2.8）, ΔfHmθ[Nd（C7H5O3）2（C6H4NO2）·H2O（s）, 298.15 K] = -（2463.1 ± 2.9） kJ/mol.

关 键 词：均匀沉淀法 稀土配合物 芳香羧酸 光谱特性 标准摩尔生成焓 

分 类 号：O641.4[理学—物理化学]