title: Preparation and magnetic properties of metal-complexes from N-t-butyl-N-oxidanyl-2-amino-(nitronyl nitroxide).
abstract: Metal complexation reactions of N-t-butyl-N-oxidanyl-2-amino(nitronyl nitroxide) diradical (1) with M(hfac)2 (M: Mn or Cu) were investigated. These reactions were found to be very sensitive to the type of metal ion employed. Complex [Mn(hfac)2·1], consisting of Mn(hfac)2 and diradical 1, was readily prepared by mixing the components. However, the reaction of Cu(hfac)2 with 1 or N-t-butyl-N-oxidanyl-2-amino(iminonitroxide) diradical (2) involved the reduction of the diradical to the N-t-butyl-N-oxidanide-2-amino(iminonitroxide) radical anion (3) and finally produced the polymer-chain complex [Cu2(hfac)2·32·Cu(hfac)2]n. The structures of these complexes were elucidated by X-ray analysis, and their magnetic properties were investigated in detail. The temperature dependence of χpT (χp: magnetic susceptibility) for [Mn(hfac)2·1] exhibited a strong antiferromagnetic interaction (H = -2JS1·S2, J/kB = -217 K) between the Mn(II) spin (S = 5/2) and the diradical 1 spin (S = 1). However, the χpT-T plots for [Cu2(hfac)2·32·Cu(hfac)2]n indicated the presence of several magnetic interactions: a large ferromagnetic interaction (J/kB = 510 K) between iminonitroxide 3 and the imino-coordinating Cu(II) atom, a moderately large ferromagnetic interaction (J/kB = 58 K) between the iminonitroxide and (iminonitroxide oxygen)-coordinating Cu(hfac)2, and a weak antiferromagnetic interaction (J/kB = -1.4 K) between the two Cu(hfac)-3 moieties within a Cu2O2 square.
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka City University , Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Furui
authors.forename: Shuichi
authors.initials: S
authors.lastname: Suzuki
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Kozaki
authors.forename: Daisuke
authors.initials: D
authors.lastname: Shiomi
authors.forename: Kazunobu
authors.initials: K
authors.lastname: Sato
authors.forename: Takeji
authors.initials: T
authors.lastname: Takui
authors.forename: Keiji
authors.initials: K
authors.lastname: Okada
authors.forename: Evgeny V
authors.initials: EV
authors.lastname: Tretyakov
authors.forename: Svyatoslav E
authors.initials: SE
authors.lastname: Tolstikov
authors.forename: Galina V
authors.initials: GV
authors.lastname: Romanenko
authors.forename: Victor I
authors.initials: VI
authors.lastname: Ovcharenko