Yang Qi, Liu Tingting, Tan Jiwen, Zhu Liyang, Liu Qian, Yang Suliang, Tian Guoxin
Department of Radiochemistry, China Institute of Atomic Energy, Beijing 102413, China.
Nuclear Chemical Engineering Department, Harbin Engineering University, Harbin 150001, China.
Inorg Chem. 2022 Jun 27;61(25):9381-9384. doi: 10.1021/acs.inorgchem.2c00808. Epub 2022 May 31.
The complexation of uranium(VI) [U(VI)] with dipicolinic acid was revisited with respect to the missing protonated complex species existing in acidic solutions. For the first time, the presence of the protonated complex, UOHL, in aqueous solutions was confirmed and the stability constant was determined by fluorescence spectroscopy. Considering the protonated species, which was missing in previous investigations, the overestimated stability constants of the two known complexes, UOL and UOL, were carefully reevaluated with potentiometry using -(2-hydroxyethyl)ethylenediamine-,','-triacetic acid as a competing ligand. While a single crystal of the solid compound UO(HL)(HO) with two monoprotonated HL bonding UO in a tridentate mode was successfully grown from aqueous solutions, the corresponding complex species UO(HL)(aq) could not yet be clearly identified and characterized.
针对酸性溶液中缺失的质子化络合物物种，对铀（VI）[U(VI)]与二吡啶甲酸的络合作用进行了重新研究。首次证实了水溶液中质子化络合物UOHL的存在，并通过荧光光谱法测定了其稳定常数。考虑到先前研究中缺失的质子化物种，使用-(2-羟乙基)乙二胺-N,N,N',N'-四乙酸作为竞争配体，通过电位滴定法仔细重新评估了两种已知络合物UOL和UOL被高估的稳定常数。虽然成功地从水溶液中生长出了固体化合物UO(HL)(H₂O)的单晶，其中两个单质子化的HL以三齿模式键合UO，但相应的络合物物种UO(HL)(aq)尚未得到明确鉴定和表征。
