title: An amphoteric reactivity of a mixed-valent bis(μ-oxo)dimanganese(III,IV) complex acting as an electrophile and a nucleophile.
abstract: A mixed-valent bis(μ-oxo)dimanganese(III,IV) complex, [(dpaq)Mn(III)(O)2Mn(IV)(dpaq)](+) (1), was prepared by reacting a hydroxomanganese(III) complex, [(dpaq)Mn(III)(OH)](+), with hydrogen peroxide in the presence of triethylamine. The mixed-valent bis(μ-oxo)dimanganese(III,IV) complex (1) was well characterised by UV-vis, EPR and CSI-MS techniques. The electrophilic reactivity of 1 was investigated in the oxidation of 2,6-di-tert-butylphenol derivatives by 1, in which the relative rate afforded a good Hammett correlation with a ρ value of -1.0. The nucleophilic character of 1 was then investigated in aldehyde deformylation reactions, using 2-phenylpropionaldehyde (2-PPA) and benzaldehyde derivatives as substrates. In contrast to the case of the reaction of 1 with 2,6-di-tert-butylphenol derivatives, a positive ρ value of 0.89 was obtained in the Hammett plot, demonstrating that the bis(μ-oxo)-dimanganese(III,IV) complex is an active nucleophilic oxidant. Thus, 1 exhibited an amphoteric reactivity in both electrophilic and nucleophilic oxidative reactions.
authors.affiliation: Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea. wwnam@ewha.ac.kr.
authors.forename: Muniyandi
authors.initials: M
authors.lastname: Sankaralingam
authors.affiliation: Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea. wwnam@ewha.ac.kr.
authors.forename: So Hyun
authors.initials: SH
authors.lastname: Jeon
authors.affiliation: Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea. wwnam@ewha.ac.kr.
authors.forename: Yong-Min
authors.initials: YM
authors.lastname: Lee
authors.affiliation: Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea. wwnam@ewha.ac.kr.
authors.forename: Mi Sook
authors.initials: MS
authors.lastname: Seo
authors.affiliation: Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea. wwnam@ewha.ac.kr and Department of Material and Life Science, Graduate School of Engineering, Osaka University, ALCA and SENTAN, Japan Science and Technology Agency (JST), 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan. fukuzumi@chem.eng.osaka-u.ac.jp.
authors.forename: Kei
authors.initials: K
authors.lastname: Ohkubo
authors.affiliation: Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea. wwnam@ewha.ac.kr and Department of Material and Life Science, Graduate School of Engineering, Osaka University, ALCA and SENTAN, Japan Science and Technology Agency (JST), 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan. fukuzumi@chem.eng.osaka-u.ac.jp.
authors.forename: Shunichi
authors.initials: S
authors.lastname: Fukuzumi
authors.affiliation: Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea. wwnam@ewha.ac.kr.
authors.forename: Wonwoo
authors.initials: W
authors.lastname: Nam