期刊
INORGANIC CHEMISTRY
卷 49, 期 23, 页码 10960-10969出版社
AMER CHEMICAL SOC
DOI: 10.1021/ic101378s
关键词
-
资金
- Grant Agency of the Czech Republic [203/09/1056]
- Ministry of Education of the Czech Republic [MSM0021620857]
- Hungarian Science Foundation [OTKA K69098, TAMOP-4.2.1/B-09/1/KONV-2010-0007]
- ANR, France
Given the practical advantages of the Ga-68 isotope in positron emission tomography applications, gallium complexes are gaining increasing importance in biomedical imaging. However, the strong tendency of Ga3+ to hydrolyze and the slow formation and very high stability of macrocyclic complexes altogether render Ga3+ coordination chemistry difficult and explain why stability and kinetic data on Ga3+ complexes are rather scarce. Here we report solution and solid-state studies of Ga3+ complexes formed with the macrocyclic ligand 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid, (DOTA)(4-), and its mono(n-butylamide) derivative, (DO3AM(Bu))(3-). Thermodynamic stability constants, log K(GaDOTA) = 26.05 and log K(GaDO3AM(Bu)) = 24.64, were determined by out-of-cell pH-potentiometric titrations. Due to the very slow formation and dissociation of the complexes, equilibration times of up to similar to 4 weeks were necessary. The kinetics of complex dissociation were followed by Ga-71 NMR under both acidic and alkaline conditions. The GaDOTA complex is significantly more inert (tau(1/2) similar to 12.2 d at pH = 0 and tau(1/2) similar to 6.2 h at pH = 10) than the GaDO3AM(Bu) analogue (tau(1/2) similar to 2.7 d at pH = 0 and tau(1/2) similar to 0.7 h at pH = 10). Nevertheless, the kinetic inertness of both chelates is extremely high and approves the application of Ga3+ complexes of such DOTA-like ligands in molecular imaging. The solid-state structure of the GaDOTA complex, crystallized from a strongly acidic solution (pH < 1), evidenced a diprotonated form with protons localized on the free carboxylate pendants.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据