Laboratoire de Reconnaissance Ionique et Chimie de Coordination, SCIB, UMR-E CEA/UJF-Grenoble 1, INAC, CEA-Grenoble, 17 rue des Martyrs, Grenoble, F-38054, France.
Inorg Chem. 2013 Jun 17;52(12):7078-86. doi: 10.1021/ic4006218. Epub 2013 Jun 4.
The synthesis, structure, and reactivity of a new complex of U(IV) with the tridentate Schiff base ligand Menaphtquinolen are reported. The reduction of the bis-ligand complexes [UX2((Me)naphtquinolen)2] (X = Cl, (1-Cl) ; I (1-I)) with potassium metal affords the U(IV) complex of the new tetranionic hexadentate ligand μ-bis-(Me)naphtquinolen formed through the intramolecular reductive coupling of the imino groups of each (Me)naphtquinolen unit. The solid state structure of the [U(μ-bis-(Me)naphtquinolen)]2 dimer 2 isolated from toluene confirms the presence of a U(IV) complex of the reduced ligand. Reactivity studies with molecular oxygen and 9,10-phenanthrenequinone show that complex 2 can act as a multielectron reducing agent releasing two electrons through the cleavage of the C-C bond to restore the original imino function of the ligand. In the resulting U(IV) and U(VI) complexes [U(9,10-phenanthrenediol)((Me)naphtquinolen)2], 3, and [UO2((Me)naphtquinolen)2], 4, the restored tridentate Schiff base allows for the coordination of the reduced substrate to the metal. Electrochemical studies of complex 2 show the presence of irreversible ligand centered reduction processes and of a reversible U(IV)/U(III) couple.
报告了一种新型 U(IV)配合物与三齿席夫碱配体 Menaphtquinolen 的合成、结构和反应性。双配体配合物 [UX2((Me)naphtquinolen)2]（X = Cl，（1-Cl）；I（1-I））与钾金属的还原得到了新的四阴离子六齿配体 μ-双-（Me）naphtquinolen 的 U(IV)配合物，该配体通过每个（Me）naphtquinolen 单元的亚氨基的分子内还原偶联形成。从甲苯中分离出的 [U(μ-bis-(Me)naphtquinolen)]2 二聚体 2 的固态结构证实了还原配体的存在。与分子氧和 9,10-菲醌的反应性研究表明，配合物 2 可以作为多电子还原剂，通过 C-C 键的断裂释放两个电子，从而恢复配体的原始亚氨基功能。在生成的 U(IV)和 U(VI)配合物 [U(9,10-phenanthrenediol)((Me)naphtquinolen)2]，3 和 [UO2((Me)naphtquinolen)2]，4 中，恢复的三齿席夫碱允许还原的底物与金属配位。配合物 2 的电化学研究表明存在不可逆的配体中心还原过程和可逆的 U(IV)/U(III)偶。
