title: Gd2@C79N: isolation, characterization, and monoadduct formation of a very stable heterofullerene with a magnetic spin state of S = 15/2.
abstract: The dimetallic endohedral heterofullerene (EHF), Gd(2)@C(79)N, was prepared and isolated in a relatively high yield when compared with the earlier reported heterofullerene, Y(2)@C(79)N. Computational (DFT), chemical reactivity, Raman, and electrochemical studies all suggest that the purified Gd(2)@C(79)N, with the heterofullerene cage, (C(79)N)(5-) has comparable stability with other better known isoelectronic metallofullerene (C(80))(6-) cage species (e.g., Gd(3)N@C(80)). These results describe an exceptionally stable paramagnetic molecule with low chemical reactivity with the unpaired electron spin density localized on the internal diatomic gadolinium cluster and not on the heterofullerene cage. EPR studies confirm that the spin state of Gd(2)@C(79)N is characterized by a half-integer spin quantum number of S = 15/2. The spin (S = ½) on the N atom of the fullerene cage and two octet spins (S = 7/2) of two encapsulated gadoliniums are coupled with each other in a ferromagnetic manner with a small zero-field splitting parameter D. Because the central line of Gd(2)@C(79)N is due to the Kramer's doublet with a half-integer spin quantum number of S = 15/2, this relatively sharp line is prominent and the anisotropic nature of the line is weak. Interestingly, in contrast with most Gd(3+) ion environments, the central EPR line (g = 1.978) is observable even at room temperature in a toluene solution. Finally, we report the first EHF derivative, a diethyl bromomalonate monoadduct of Gd(2)@C(79)N, which was prepared and isolated via a modified Bingel-Hirsch reaction.
authors.affiliation: Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA.
authors.forename: Wujun
authors.initials: W
authors.lastname: Fu
authors.forename: Jianyuan
authors.initials: J
authors.lastname: Zhang
authors.forename: Tim
authors.initials: T
authors.lastname: Fuhrer
authors.forename: Hunter
authors.initials: H
authors.lastname: Champion
authors.forename: Ko
authors.initials: K
authors.lastname: Furukawa
authors.forename: Tatsuhisa
authors.initials: T
authors.lastname: Kato
authors.forename: James E
authors.initials: JE
authors.lastname: Mahaney
authors.forename: Brian G
authors.initials: BG
authors.lastname: Burke
authors.forename: Keith A
authors.initials: KA
authors.lastname: Williams
authors.forename: Kenneth
authors.initials: K
authors.lastname: Walker
authors.forename: Caitlyn
authors.initials: C
authors.lastname: Dixon
authors.forename: Jiechao
authors.initials: J
authors.lastname: Ge
authors.forename: Chunying
authors.initials: C
authors.lastname: Shu
authors.forename: Kim
authors.initials: K
authors.lastname: Harich
authors.forename: Harry C
authors.initials: HC
authors.lastname: Dorn
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D037741:Fullerenes / Q000737:chemistry*; D005682:Gadolinium; D008280:Magnetics
chemical_list: D037741:Fullerenes; D005682:Gadolinium