title: Redox modulation of para-phenylenediamine by substituted nitronyl nitroxide groups and their spin states.
abstract: Three kinds of para-phenylenediamine (PDA) derivatives bearing nitronyl nitroxide (NN) groups were prepared and characterized on the basis of the electrochemical, electron spin resonance (ESR) spectroscopic, absorption spectroscopic, and magnetic susceptibility measurements. It was clarified that the oxidation potential of the central PDA unit is strongly influenced by the numbers of substituted electron-withdrawing NN groups. In addition, the intervalence charge transfer in the central PDA unit was detected in the monocationic states of the PDAs with two NN groups, indicating the coexistence of the localized spins and the delocalized spin on theses molecules. Moreover, pulsed ESR measurements confirmed that the delocalized spin on the central PDA unit and the localized two spins on the NN groups were ferromagnetically coupled in the monocationic states.
authors.affiliation: Department of Molecular Engineering, Graduate School of Engineering, Kyoto University , Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Ito
authors.forename: Ryohei
authors.initials: R
authors.lastname: Kurata
authors.forename: Daisuke
authors.initials: D
authors.lastname: Sakamaki
authors.forename: Soichiro
authors.initials: S
authors.lastname: Yano
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Kono
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Nakano
authors.forename: Ko
authors.initials: K
authors.lastname: Furukawa
authors.forename: Tatsuhisa
authors.initials: T
authors.lastname: Kato
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Tanaka