A Fully Charge-Delocalized Two-Dimensional Porphyrin System with Two Different Class III States

详细信息    查看全文

• 作者：Kentaro Mishiba ; Masanori Ono ; Dr. Yuya Tanaka and Prof. Dr. Munetaka Akita
• 刊名：Chemistry - A European Journal
• 出版年：2017
• 出版时间：February 10, 2017
• 年：2017
• 卷：23
• 期：9
• 页码：2067-2076
• 全文大小：4531K
• ISSN：1521-3765

文摘

Understanding of charge-delocalization over two-dimensional (2D) frameworks is a further step in the path towards the development of molecular nanodevices and nanomaterials. Here, we report a porphyrin–nickel complex with four peripheral redox-active ruthenium pendants (1). A cyclic voltammogram of compound 1 displays reversible five-electron, four redox waves with large potential separations, suggesting that one-electron- (1⁺) and two-electron-oxidized species (1²⁺) are thermodynamically stable with respect to disproportionation. The paramagnetic one-electron-oxidized species 1⁺ prepared by a comproportionation reaction of compounds 1 and 1²⁺, turns out to be a highly charge-delocalized two-dimensional class III compound as clearly indicated by its characteristic intervalence charge-transfer (IVCT) band as is further supported by IR and ESR spectroscopy as well as DFT and time-dependent (TD) DFT calculations. Furthermore, the diamagnetic dicationic species 1²⁺ has a spin-paired electronic structure with a fully charge-averaged class III character. The substantial contribution of the cumulenic structures to compound 1²⁺ is confirmed by ¹³C NMR and IR spectroscopy as well as X-ray structure analyses. Such unique electronic features of the 2D systems provide a clue to development of nanoscale molecular devices.