Koban A, Bernhard G
Forschungszentrum Dresden-Rossendorf e.V., Institute of Radiochemistry, P.O. Box 510119, D-01314 Dresden, Germany.
J Inorg Biochem. 2007 May;101(5):750-7. doi: 10.1016/j.jinorgbio.2007.01.001. Epub 2007 Jan 17.
We present the complex formation of the uranyl ion (UO(2)(2+)) in the aqueous system with phosphocholine, O-phosphoethanolamine and O-phosphoserine. These phosphonates (R-O-PO(3)(2-)) represent the hydrophilic head groups of phospholipids. The complexation was investigated by time-resolved laser-induced fluorescence spectroscopy (TRLFS) at pH=2-6. An increase of the fluorescence intensity, connected with a strong red-shift of about 8 nm compared to the free uranyl ion, indicates a complex formation between UO(2)(2+) and the phosphonates already at pH=2. Even at pH=6 these complexes prevail over the uranyl hydroxide and carbonate species, which are generated naturally at this pH. At pH=4 and higher a 1:2 complex between uranyl and O-phosphoserine was found. Complexes with a metal-to-ligand ratio of 1:1 were observed for all other ligands. Fluorescence lifetimes, emission maxima and complex stability constants at T=22+/-1 degrees C are reported. The TRLFS spectra of uranyl complexes with two phosphatidic acids (1,2-dimyristoyl-sn-glycero-3-phosphate and 1,2-dipalmitoyl-sn-glycero-3-phosphate), which represent the apolaric site of phospholipids, show in each case two different species.
我们展示了在水体系中铀酰离子（UO₂²⁺）与磷酸胆碱、O-磷酸乙醇胺和O-磷酸丝氨酸形成的络合物。这些膦酸盐（R - O - PO₃²⁻）代表磷脂的亲水头部基团。通过时间分辨激光诱导荧光光谱法（TRLFS）在pH = 2 - 6范围内研究了络合作用。荧光强度的增加，与游离铀酰离子相比有大约8 nm的强烈红移，表明在pH = 2时UO₂²⁺与膦酸盐之间就已形成络合物。即使在pH = 6时，这些络合物也比在此pH下自然生成的氢氧化铀酰和碳酸铀酰物种占优势。在pH = 4及更高时，发现铀酰与O-磷酸丝氨酸形成1:2的络合物。对于所有其他配体，观察到金属与配体比例为1:1的络合物。报告了在T = 22 ± 1℃时的荧光寿命、发射最大值和络合物稳定性常数。铀酰与两种磷脂酸（1,2-二肉豆蔻酰-sn-甘油-3-磷酸和1,2-二棕榈酰-sn-甘油-3-磷酸）形成的络合物的TRLFS光谱，这两种磷脂酸代表磷脂的非极性部位，每种情况下都显示出两种不同的物种。
