title: A Fully Charge-Delocalized Two-Dimensional Porphyrin System with Two Different Class III States.
abstract: 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 by13C 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.
authors: Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta Midori-ku, Yokohama, 226-8503, Japan.
authors: Kentaro
authors: K
authors: Mishiba
authors: Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta Midori-ku, Yokohama, 226-8503, Japan.
authors: Masanori
authors: M
authors: Ono
authors: Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta Midori-ku, Yokohama, 226-8503, Japan.
authors: Yuya
authors: http://orcid.org/0000-0002-0674-660X
authors: Y
authors: Tanaka
authors: Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta Midori-ku, Yokohama, 226-8503, Japan.
authors: Munetaka
authors: http://orcid.org/0000-0001-7007-9621
authors: M
authors: Akita
keywords: charge delocalization; metal acetylide; mixed-valence compound; porphyrinoids; ruthenium