title: Strongest Ferromagnetic Coupling in Designed Gadolinium(III)-Nitroxide Coordination Compounds.
abstract: Three novel gadolinium(III)-radical complexes [Gd(III)(hfac)3(H2O)(L)] [Gd-L; L = tert-butyl phenyl nitroxide (phNO) and its derivatives (tert-butyl 3-tolyl nitroxide and tert-butyl 4-tert-butylphenyl nitroxide)] were synthesized, and all compounds showed ferromagnetic coupling, obeying the empirical relation: out-of-plane coordination of the Gd ion from the radical π system favors ferromagnetic coupling. In particular, Gd-phNO has a considerably large torsion angle around Gd-O-N-Csp(2) (69.8(9)° on average) and the largest ferromagnetic coupling parameter (2J/kB = +18.0(4) K) in Gd-nitroxide compounds ever known. The validity of our molecular design was assessed on the basis of the magneto-structure relation analysis with many literature data including various paramagnetic ligating groups.
authors.affiliation: Department of Engineering Science, The University of Electro-Communications , Chofu, Tokyo 182-8585, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Kanetomo
authors.affiliation: Department of Engineering Science, The University of Electro-Communications , Chofu, Tokyo 182-8585, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Yoshitake
authors.affiliation: Department of Engineering Science, The University of Electro-Communications , Chofu, Tokyo 182-8585, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Ishida