化学
分子内力
未成对电子
位阻效应
铜
结晶学
反离子
分子
接受者
金属
电化学
电子受体
立体化学
光化学
离子
有机化学
物理化学
电极
物理
凝聚态物理
作者
Sławomir Domagała,Agnieszka Więckowska,J. Kowalski,Agnieszka Rogowska,Jadwiga Szydłowska,Bohdan Korybut‐Daszkiewicz,Renata Bilewicz,Krzysztof Woźniak
标识
DOI:10.1002/chem.200500777
摘要
Abstract N ‐Methylated bismacrocyclic Cu and Ni complexes were synthesised and structurally characterised in the solid state. Their properties in solution were analysed by using NMR and ESR spectroscopies and electrochemical methods. Face‐to‐face biscyclidenes linked through polymethylene chains form rectangular boxlike cations. These moieties can host some small guest molecules (water, π‐electron donating compounds) and are stabilised by a shell of neighbouring counterions. For the bismacrocyclic dinuclear complexes containing two nickel or two copper ions, the intramolecular interactions between the metallic centres are strengthened through methylation of the macrocyclic components, as compared with the nonmethylated species. We report the electron coupling created by two unpaired electrons coming from two copper centres observed by ESR spectroscopy. Methylation weakens the electron‐acceptor properties of the complexes, which leads to less effective binding of the π‐electron‐donating guests. It also increases the stability of the lower oxidation states. In the case of the copper complexes, both Cu II /Cu I and Cu II /Cu III reversible one‐electron transfers are seen in the voltammograms. These changes in properties are interpreted as the consequences of steric repulsion between the methyl substituents and the macrocyclic ring.
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