title: Photoinduced magnetization in copper octacyanomolybdate.
abstract: This article describes the studies of a photomagnetic cyanide-bridged Cu-Mo bimetallic assembly, Cu(II)(2)[Mo(IV)(CN)(8)].8H(2)O (Cu(II), S = (1)/(2); Mo(IV), S = 0) (1), which has an intervalence transfer (IT) band from Mo(IV)-CN-Cu(II) to Mo(V)-CN-Cu(I) around 480 nm. Wide-angle X-ray scattering and X-ray spectroscopic studies provide precise information about the 3D connectivity and the local environment of the transition metal ions. Irradiating with blue light causes solid 1 to exhibit a spontaneous magnetization (Curie temperature = 25 K). The thermal reversibility is carefully studied and shows the long-time stability of the photoinduced state up to 100 K. Photoreversibility is also observed; i.e., the magnetization is induced by irradiation with light below 520 nm, while the magnetization is reduced by irradiation with light above 520 nm. The UV-vis absorption spectrum after irradiation shows a decrease of the IT band and the appearance of the reverse-IT band in the region of 600-900 nm (lambda(max) = 710 nm). This UV-vis absorption spectrum is recovered to the original spectrum by irradiation with 658-, 785-, and 840-nm light. In this photomagnetic effect, the excitation of the IT band causes an electron transfer from Mo(IV) to Cu(II), producing a ferromagnetic mixed-valence isomer of Cu(I)Cu(II)[Mo(V)(CN)(8)].8H(2)O (Cu(I), S = 0; Cu(II), S = (1)/(2); Mo(V), S = (1)/(2)) (1'). 1' returns to 1 by irradiation of the reverse-IT band, which obeys the scheme for the potential energy surface in mixed-valence class II compounds.
authors.affiliation: Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan. ohkoshi@light.t.u-tokyo.ac.jp
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Ohkoshi
authors.forename: Hiroko
authors.initials: H
authors.lastname: Tokoro
authors.forename: Toshiya
authors.initials: T
authors.lastname: Hozumi
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhang
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Hashimoto
authors.forename: Corine
authors.initials: C
authors.lastname: Mathonière
authors.forename: Isabelle
authors.initials: I
authors.lastname: Bord
authors.forename: Guillaume
authors.initials: G
authors.lastname: Rombaut
authors.forename: Marc
authors.initials: M
authors.lastname: Verelst
authors.forename: Christophe
authors.initials: C
authors.lastname: Cartier dit Moulin
authors.forename: Françoise
authors.initials: F
authors.lastname: Villain