Ramírez Flor de María, Varbanov Sabi, Padilla Juan, Bünzli Jean-Claude G
Departamento de Quimica, Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca S/N. La Marquesa, Ocoyoacac. C.P. 52750, Mexico.
J Phys Chem B. 2008 Sep 4;112(35):10976-88. doi: 10.1021/jp710848m. Epub 2008 Aug 8.
The coordination ability of the hexaphosphinoylated p-tert-butylcalix[6]arene B6bL6 toward actinides is established, as well as its good separation ability of the actinide ions UO2 2+ and Th(IV) over trivalent rare earths such as La(III), Eu(III), and Y(III). Spectrophotometric titration of uranyl with B6bL6 in CH 3CN yields log beta 11 = 7.1 and log beta 12 = 12.5 for the 1:1 and 1:2 (UO2 2+/B 6bL6) species, respectively. Actinide complexes with 1:1 and 1:2 (M/L) stoichiometries are isolated and characterized by elemental analysis, IR, and UV-vis. Compounds 1 and 3 fulfill their CN = 8 just with B 6bL (6), while compounds 2 and 4 require coordinated nitrates and/or water molecules. The luminescence spectra of the uranyl complexes and the parameters such as FWMH, vibronic spacing (upsilon sp), and the U-O bond length, as well as the luminescence lifetimes, permit the understanding of the coordination chemistry of these actinide calixarene complexes. Energy transfer from the B6bL6 ligand to the uranyl ion is demonstrated to be relevant in compound 1 with Q abs = 2.0%. The uranyl complex emission reveals a biexponential decay with tau s from 210 to 220 micros and tau L from 490 to 650 micros for compounds 1 and 3, respectively. The liquid-liquid extraction results demonstrate the good extraction capability of B 6bL (6) toward actinides but not for rare earths at room temperature. The extracted species keeps the 1(cation)/1(calixarene) ratio for the UO2 2+, Th 4+, and Eu 3+ ions. A good capacity of B6bL 6 toward Th4+ ions using aqueous phase 2 containing even up to 0.3 M thorium nitrate and an organic phase of 2.47 x 10 (-4) M B6bL6 in chloroform is found. The spectroscopic properties of the isolated uranyl complexes and the extraction studies reveal a uranophilic nature of B6bL6. The molecular modeling results are in good agreement with the experimental findings.
已证实六磷酰化对叔丁基杯[6]芳烃B6bL6对锕系元素的配位能力，以及其对锕系离子UO2 2+和Th(IV)相对于三价稀土元素如La(III)、Eu(III)和Y(III)的良好分离能力。在乙腈中用B6bL6对铀酰进行分光光度滴定，对于1:1和1:2（UO2 2+/B6bL6）物种，分别得到logβ11 = 7.1和logβ12 = 12.5。分离出化学计量比为1:1和1:2（M/L）的锕系配合物，并通过元素分析、红外光谱和紫外可见光谱进行表征。化合物1和3仅与B6bL(6)形成八配位，而化合物2和4需要配位的硝酸根和/或水分子。铀酰配合物的发光光谱以及诸如半高宽、振动间距（υsp）和U-O键长等参数，以及发光寿命，有助于理解这些锕系杯芳烃配合物的配位化学。在化合物1中，已证明从B6bL6配体到铀酰离子的能量转移是相关的，Qabs = 2.0%。对于化合物1和3，铀酰配合物发射分别显示出双指数衰减，τs为210至220微秒，τL为490至650微秒。液液萃取结果表明，在室温下B6bL(6)对锕系元素具有良好的萃取能力，但对稀土元素则不然。对于UO2 2+、Th 4+和Eu 3+离子，萃取物种保持1（阳离子）/1（杯芳烃）的比例。发现在含有高达0.3 M硝酸钍的水相2和氯仿中2.47×10(-4) M B6bL6的有机相条件下，B6bL6对Th4+离子具有良好的容量。分离出的铀酰配合物的光谱性质和萃取研究揭示了B6bL6的亲铀性质。分子模拟结果与实验结果高度吻合。
