title: Switching of spin states triggered by a phase transition: spin-crossover properties of self-assembled iron(II) complexes with alkyl-tethered triazole ligands.
abstract: Iron(II) complexes of triazole derivatives having two C12 and C16 long alkyl chains, (C12trz)FeII and (C16trz)FeII, serve as novel spin-crossover materials, which display a spin-state transition in response to a phase transition. In contrast, a triazole complex with two C8 alkyl chains ((C8trz)FeII) exhibits only a poor response. EXAFS and XRD analyses of (C16trz)FeII indicate an interdigitating self-assembled structure of polynuclear iron(II) species. According to DSC, VT-IR, and VT-XRD profiles, the spin-state transition is triggered by melting of the interdigitating alkyl chains, which is likely responsible for the "lock-and-release" feature of the spin state. By virtue of the thermoreversibility of the phase transition, the spin crossover could be repeated without deterioration.
authors.affiliation: Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Tsuyohiko
authors.initials: T
authors.lastname: Fujigaya
authors.forename: Dong-Lin
authors.initials: DL
authors.lastname: Jiang
authors.forename: Takuzo
authors.initials: T
authors.lastname: Aida