López Isidoro, Cao Rui, Quist David A, Karlin Kenneth D, Le Poul Nicolas
UMR CNRS 6521, Université de Bretagne Occidentale, 6 Avenue Le Gorgeu, CS 93837, 29238, Brest Cedex 3, France.
Department of Chemistry, Johns Hopkins University, Baltimore, Maryland, 21218, USA.
Chemistry. 2017 Dec 22;23(72):18314-18319. doi: 10.1002/chem.201705066. Epub 2017 Nov 30.
Direct experimental determination of redox properties of superoxo (O ) and peroxo (O ) embedded in dicopper complexes bearing an unsymmetrical binucleating ligand was achieved using cryo-electrochemistry and cryo-spectroelectrochemistry in dichloromethane. Cyclic voltammetry for dicopper(I) (1 ) oxidation to a Cu Cu mixed-valent species (1 ) under inert atmosphere at 193 K reveals slow heterogeneous electron-transfer kinetics, indicative of a large reorganization energy. Oxygenation of the dicuprous complex 1 gives the bridged peroxo dicopper(II) species 3 , which is reversibly oxidized to the superoxo complex 2 at E =0.11 V (vs. SCE) with a small inner sphere electron-transfer reorganization energy, λ =0.54 eV, determined from variable temperature electrochemical impedance spectroscopy. The data suggest that the O /O redox process occurs directly on the O -derived core.
在二氯甲烷中，通过低温电化学和低温光谱电化学方法，直接实验测定了含有不对称双核配体的二铜配合物中嵌入的超氧（O ）和过氧（O ）的氧化还原性质。在193K的惰性气氛下，对二价铜（I）（1 ）氧化为Cu Cu混合价态物种（1 ）进行循环伏安法研究，结果显示其异相电子转移动力学缓慢，这表明存在较大的重组能。二价铜配合物1的氧化反应生成桥连过氧二价铜（II）物种3 ，该物种在E =0.11V（相对于饱和甘汞电极）时可逆氧化为超氧配合物2 ，通过变温电化学阻抗谱测定其具有较小的内球电子转移重组能，λ =0.54eV。数据表明，O /O氧化还原过程直接发生在O衍生的核心上。
