Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, H-4032 Debrecen, Hungary.
Department of Inorganic and Analytical Chemistry, Faculty of Science and Technology, University of Debrecen, H-4032 Debrecen, Hungary.
Inorg Chem. 2021 Sep 20;60(18):14253-14262. doi: 10.1021/acs.inorgchem.1c01765. Epub 2021 Aug 31.
In recent years Auger electron emitters have been suggested as promising candidates for radiotherapy with no side effects in cancer treatment. In this work we report a detailed coordination chemistry study of [Sb(PCTA)] (PCTA: 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene-3,6,9-triacetic acid), a macrocyclic aminopolycarboxylate-type complex of antimony(III), whose Sb isotope could be a suitable low-energy electron emitter for radiotherapy. The thermodynamic stability of the chelate obtained by pH-potentiometry and UV-vis spectrophotometry is high enough (log = 23.2(1)) to prevent the hydrolysis of the metal ion near physiological pH. The formation of [Sb(PCTA)] is confirmed by NMR and electrospray ionization mass spectrometry measurements in solution; furthermore, the structure of [Sb(PCTA)]·NaCl·3HO and [Sb(PCTA)]·HCl·3HO is described by X-ray and density functional theory calculations. Consequently, the [Sb(PCTA)] is the first thermodynamically stable antimony(III) complex bearing polyamino-polycarboxylate macrocyclic platform. Our results demonstrate the potential of rigid (pyclen derivative) ligands as chelators for future applications of Sb(III) in a targeted radiotherapy based on the Sb isotope.
近年来，Auger 电子发射器被认为是一种有前途的候选者，可以在癌症治疗中实现无副作用的放射治疗。在这项工作中，我们报告了对[ Sb(PCTA)]（PCTA：3,6,9,15-四氮杂环十五烷-3,6,9-三乙酸）的详细配位化学研究，[ Sb(PCTA)]是一种三价锑的大环多氨基多羧酸型配合物，其 Sb 同位素可以作为放射治疗的合适低能电子发射器。通过 pH 电位滴定和紫外可见分光光度法获得的螯合物的热力学稳定性足够高（log = 23.2(1)），可以防止金属离子在生理 pH 附近发生水解。通过 NMR 和电喷雾电离质谱测量在溶液中证实了[ Sb(PCTA)]的形成；此外，还通过 X 射线和密度泛函理论计算描述了[ Sb(PCTA)]·NaCl·3HO 和[ Sb(PCTA)]·HCl·3HO 的结构。因此，[ Sb(PCTA)]是第一个热力学稳定的含有多氨基多羧酸大环平台的三价锑配合物。我们的结果表明，刚性（pclen 衍生物）配体作为螯合剂在基于 Sb 同位素的靶向放射治疗中具有应用潜力。
