title: Cyanide-bridged [Fe8M6] clusters displaying single-molecule magnetism (M=Ni) and electron-transfer-coupled spin transitions (M=Co).
abstract: Cyanide-bridged metal complexes of [Fe(8)M(6)(μ-CN)(14)(CN)(10)(tp)(8)(HL)(10)(CH(3)CN)(2)][PF(6)](4)⋅n CH(3)CN⋅m H(2)O (HL=3-(2-pyridyl)-5-[4-(diphenylamino)phenyl]-1H-pyrazole), tp(-) =hydrotris(pyrazolylborate), 1: M=Ni with n=11 and m=7, and 2: M=Co with n=14 and m=5) were prepared. Complexes 1 and 2 are isomorphous, and crystallized in the monoclinic space group P2(1)/n. They have tetradecanuclear cores composed of eight low-spin (LS) Fe(III) and six high-spin (HS) M(II) ions (M=Ni and Co), all of which are bridged by cyanide ions, to form a crown-like core structure. Magnetic susceptibility measurements revealed that intramolecular ferro- and antiferromagnetic interactions are operative in 1 and in a fresh sample of 2, respectively. Ac magnetic susceptibility measurements of 1 showed frequency-dependent in- and out-of-phase signals, characteristic of single-molecule magnetism (SMM), while desolvated samples of 2 showed thermal- and photoinduced intramolecular electron-transfer-coupled spin transition (ETCST) between the [(LS-Fe(II))(3) (LS-Fe(III))(5)(HS-Co(II))(3)(LS-Co(III))(3)] and the [(LS-Fe(III))(8)(HS-Co(II))(6)] states.
authors.affiliation: Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Japan.
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Mitsumoto
authors.forename: Emiko
authors.initials: E
authors.lastname: Oshiro
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nishikawa
authors.forename: Takuya
authors.initials: T
authors.lastname: Shiga
authors.forename: Yasuhisa
authors.initials: Y
authors.lastname: Yamamura
authors.forename: Kazuya
authors.initials: K
authors.lastname: Saito
authors.forename: Hiroki
authors.initials: H
authors.lastname: Oshio