Regueiro-Figueroa Martín, Gündüz Serhat, Patinec Véronique, Logothetis Nikos K, Esteban-Gómez David, Tripier Raphaël, Angelovski Goran, Platas-Iglesias Carlos
Grupo QUICOOR, Centro de Investigaciones Científicas Avanzadas (CICA) and Departamento de Química Fundamental, Universidade da Coruña , Campus da Zapateira, Rúa da Fraga 10, 15008 A Coruña, Spain.
MR Neuroimaging Agents, Max Planck Institute for Biological Cybernetics , Spemannstr. 41, 72076 Tübingen, Germany.
Inorg Chem. 2015 Nov 2;54(21):10342-50. doi: 10.1021/acs.inorgchem.5b01719. Epub 2015 Oct 15.
We report the heteroditopic ligand H5L, which contains a DO3A unit for Gd(3+) complexation connected to an NO2A moiety through a N-propylacetamide linker. The synthesis of the ligand followed a convergent route that involved the preparation of 1,4-bis(tert-butoxycarbonylmethyl)-1,4,7-triazacyclononane following the orthoamide strategy. The luminescence lifetimes of the Tb((5)D4) excited state measured for the TbL complex point to the absence of coordinated water molecules. Density functional theory calculations and (1)H NMR studies indicate that the EuL complex presents a square antiprismatic coordination in aqueous solution, where eight coordination is provided by the seven donor atoms of the DO3A unit and the amide oxygen atom of the N-propylacetamide linker. Addition of Zn(2+) to aqueous solutions of the TbL complex provokes a decrease of the emission intensity as the emission lifetime becomes shorter, which is a consequence of the coordination of a water molecule to the Tb(3+) ion upon Zn(2+) binding to the NO2A moiety. The relaxivity of the GdL complex recorded at 7 T (25 °C) increases by almost 150% in the presence of 1 equiv of Zn(2+), while Ca(2+) and Mg(2+) induced very small relaxivity changes. In vitro magnetic resonance imaging experiments confirmed the ability of GdL to provide response to the presence of Zn(2+).
我们报道了异双齿配体H5L，它含有一个用于与Gd(3+)络合的DO3A单元，通过N-丙基乙酰胺连接基与一个NO2A部分相连。该配体的合成采用了一种汇聚路线，其中涉及按照原酰胺策略制备1,4-双(叔丁氧羰基甲基)-1,4,7-三氮杂环壬烷。对TbL络合物测量的Tb((5)D4)激发态的发光寿命表明不存在配位水分子。密度泛函理论计算和(1)H NMR研究表明，EuL络合物在水溶液中呈现出方形反棱柱配位，其中DO3A单元的七个供体原子和N-丙基乙酰胺连接基的酰胺氧原子提供了八配位。向TbL络合物的水溶液中加入Zn(2+)会导致发射强度降低，因为发射寿命变短，这是由于Zn(2+)与NO2A部分结合时水分子与Tb(3+)离子配位的结果。在7 T（25°C）下记录的GdL络合物的弛豫率在存在1当量Zn(2+)的情况下增加了近两倍，而Ca(2+)和Mg(2+)引起的弛豫率变化非常小。体外磁共振成像实验证实了GdL对Zn(2+)存在做出响应的能力。
