摘要
本文研究了新型锕系元素多价整合剂——N,N′,N″-三(2,3-二羟基-5-磺酸基苯甲酰)1,5,10-三氮杂癸烷(简写为3,4-LICAMS)及其与U(Ⅳ),U(Ⅵ)体系的溶液化学行为。对配体质子解离过程、紫外可见的电子吸收光谱、溶液反应机理、配合物的组成、生成条件、配位原子的位置及配合物的稳定常数测定等方面进行了探讨。结果表明3,4-LICAMS通过它的六个酚羟基中的氧原子,在生理pH(7.4)条件下能强烈地与U(Ⅳ),U(Ⅵ)配合,生成一系列稳定的配合物。
This paper reports the solution chemistry behavior of N,N' ,N'-tris (2, 3-dihydroxy-5-sulfoben-zoyl)-1,5,10-triazadecane(3, 4-LICAMS)with U( IV )and U( VI) using potentiometric titration and spectrophotometric titration methods.The titration curve of the free tricatechol ligand, 3,4-LICAMS shows an inflection at m = 3 (m is moles base added per mole ligand or metal ion) and pH=9. 2. This represents the dissociation of the three phenolic hydrogens ortho to the carbonyl. The ligand protonation constants are calculated by nonlinear least square BETA programme, CDC CYBER 170/825 computer. The electron absorption spectra of benzen,catechol and 3,4-LICAMS are compared.At high pH the six phenolic oxygens derived from catecholate group in 3,4-LICAMS form a high-spin octahedral complex around U(IV) or U(VI). The titration curve of one to one 3,4-LICAMS to U( IV ) shows slow solution equilibrium at m = 4, pH = 3. 8 and a break at m = 5, pH = 5. 9. This curve is lower than the curve of free ligand (3, 4-LICAMS). The precipitation of (U(OH)4) x is not produced even at pH= 10. 5. It indicates that 3, 4-LICAMS can strongly combine with U( IV ) . The electron absorption spectra of the system of one to one 3,4-LICAMS to U( IV ) are shifted to long wave side with the increase of pH. All of the spectra coincide in △λ= 250-350 nm at pH = 3. 8, then separate from each other at pH= 3. 8 (at pH= 5. 8 for free ligand, 3, 4-LICAMS) and finally coincide again at pH=8. 78-10. 2. There are two isosbestic points at 374 and 485nm,pH=5. 96-9. 31,corresponding to the equilibrium, (UL)5- +H + (UHL)4-. The formation constants of (UL)5-, (UHL)4-,(UH2L)3-are calculated to be lgβ110 =43. 40,lgβ111 =46. 51 and lgβ112 =50. 23.3,4-LICAMS can strongly coordinate with U( VI) too,but the stability of complexes are less than that of U (IV ) . The titration curve of ratio 1:1 of 3,4-LICAMS to U( VI ) shows a slight break at m = 3 pH=5. 01 and a big break at m =5, pH = 8. 70. The spectra are separated from each other at pH = 4. 53 in △λ=250-350nm.
出处
《核化学与放射化学》
CAS
CSCD
北大核心
1992年第1期8-16,共9页
Journal of Nuclear and Radiochemistry
关键词
锕系元素
螯合剂
溶液化学
Actinide, Complex, Solution chemistry.
