水溶性N,N-二烷基二甘酰胺酸与U(Ⅵ)的配位化学  

Coordination Chemistry of Water-Soluble N,N-Dialkyl-Diglycolamic Acid With U(Ⅵ)

作　　者：高成琪 全葳 杨琪 张燕[1] 杨雅婷 徐超 柳倩 郝轩 杨素亮[1] 田国新[1,4] GAO Cheng-qi;QUAN Wei;YANG Qi;ZHANG Yan;YANG Ya-ting;XU Chao;LIU Qian;HAO Xuan;YANG Su-liang;TIAN Guo-xin(China Institute of Atomic Energy,P.O.Box 275(26),Beijing 102413,China;Nuclear and Radiation Safety Center,Beijing 100082,China;College of Nuclear Science and Technology,Harbin Engineering University,Harbin 150001,China;Institute of Nuclear and New Energy Technology,Tsinghua University,Beijing 100084,China)

机构地区：[1]中国原子能科学研究院放射化学研究所,北京102413 [2]生态环境部核与辐射安全中心,北京100082 [3]哈尔滨工程大学核科学与技术学院,黑龙江哈尔滨150001 [4]清华大学核能与新能源技术研究院,北京100084

出　　处：《核化学与放射化学》2024年第4期325-333,I0002,共10页Journal of Nuclear and Radiochemistry

摘　　要：研究了两种结构相似小分子配体N,N-二甲基二甘酰胺酸(HDMDGA,HL^(Ⅰ))和N,N-二乙基二甘酰胺酸(HDEDGA,HL^(Ⅱ))与铀酰离子的配位化学。在1.0 mol/L NaClO_(4)介质中,分别用电位滴定法和吸收光谱滴定法测定了两种配体的质子化常数以及UO_(2)L^(+)、UO_(2)L_(2)(L=L^(Ⅰ)、L^(Ⅱ))的配合物稳定常数,并解析获得各物种的标准摩尔吸收谱。结合拉曼光谱滴定方法,获得了各配合物物种的相对标准拉曼光谱。室温条件下利用缓慢挥发法培养了UO_(2)L_(2)^(Ⅱ)晶体,单晶X射线衍射分析结果表明该晶体属单斜晶系,空间点群为P2_(1)/c。具体结构参数为:a=15.5096(6)?(1?=0.1 nm),b=7.7934(3)?,c=11.3732(4)?,α=90°,β=97.388(4)°,γ=90°,Z=2。水溶液中配合物稳定常数以及晶体中U-O键长比较的结果均表明,虽然两种配体的结构相似,质子化常数也几乎相同,但与UO_(2)^(2+)的配位能力存在一定差异,HDEDGA与UO_(2)^(2+)形成的配合物稳定性更高。与UO_(2)L_(2)^(Ⅰ)配合物晶体相似,UO_(2)L_(2)^(Ⅱ)晶体中L^(Ⅱ-)同样以三齿模式与UO_(2)^(2+)形成配合物,3个氧原子(酰胺氧、醚氧和羧酸氧)均在赤道平面与线性的UO_(2)^(2+)配位。UO_(2)L_(2)^(Ⅱ)晶体漫反射光谱的特征与水溶液中相应组成配合物的吸收光谱有显著差异;且对于两种配体,水溶液中水合铀酰离子与1:1配合物(金属:配体)的铀酰离子特征拉曼光谱峰位移的差值,均显著大于1:1配合物与1:2配合物的差值。因此可推断,水溶液中1:2配合物的结构应不同于配合物晶体。In this work,the coordination chemistry of the uranyl ion(UO_(2)^(2+)) with N,N-dimethyldiglycolamic acid(HDMDGA,HL^(Ⅰ)) and N,N-diethyl-diglycolamic acid(HDEDGA,HL^(Ⅱ)) has been systematically studied through thermodynamic and structural analysis,by means of both potentiometric and spectroscopic titration,as well as Raman spectroscopy and X-ray diffractometry.The protonation constants of L~-(L=L^(Ⅰ),L^(Ⅱ)) and the stability constants of the uranyl complexes were determined by potentiometric and spectroscopic titrations in 1.0 mol/L NaClO_(4),with the molar absorption spectra of all species deconvoluted in the process of the latter titration.Besides,the standard Raman spectra of various complexes were confirmed by Raman spectroscopic titration.Furthermore,the single crystal of compound UO_(2)L_(2)^(Ⅱ) was obtained by slow evaporation of aqueous solution containing uranyl ion and L^(Ⅱ) ligands at room temperature.X-ray diffraction analysis shows a monoclinic crystal system in P2_1/c space group,with lattice parameters:a=15.5096(6) A(1 A=0.1 nm),b=7.7934(3) A,c=11.373 2(4) A,α=90°,β=97.388(4)°,γ=90°and Z=2.Although both ligands show a similar structure and protonation constant,the different values of stability constant in aqueous solution and the different bond length of U-O in two complexes indicate the distinct coordination ability for two ligands with UO_(2)^(2+),where HDEDGA performs better.Like the crystal structure of UO_(2)L_(2)^(Ⅰ),the ligand L^(Ⅱ) in the UO_(2)L_(2)^(Ⅱ) complex coordinates with UO_(2)^(2+) in a tridentate manner,with three oxygen atoms(amide oxygen,ether oxygen and carboxylic acid oxygen) coordinating with the linear UO_(2)^(2+) at the equatorial plane.In addition,the diffuse reflectance spectra of the UO_(2)L_(2)^(Ⅱ) crystal show characteristics significantly different from the absorption spectra of the corresponding complex in the aqueous solution.Meanwhile,the Raman shift of the characteristic peak of uranyl ion between hydrated uranyl ion and the 1:1 complex(U

关 键 词：UO_(2)^(2+) N N-二烷基二甘酰胺酸 配位稳定常数 晶体结构 拉曼光谱 

分 类 号：TL12[核科学技术—核能科学] O615.11[理学—无机化学]