title: A switchable molecular rotator: neutron spectroscopy study on a polymeric spin-crossover compound.
abstract: A quasielastic neutron scattering and solid-state (2)H NMR spectroscopy study of the polymeric spin-crossover compound {Fe(pyrazine)[Pt(CN)(4)]} shows that the switching of the rotation of a molecular fragment--the pyrazine ligand--occurs in association with the change of spin state. The rotation switching was examined on a wide time scale (10(-13)-10(-3) s) by both techniques, which clearly demonstrated the combination between molecular rotation and spin-crossover transition under external stimuli (temperature and chemical). The pyrazine rings are seen to perform a 4-fold jump motion about the coordinating nitrogen axis in the high-spin state. In the low-spin state, however, the motion is suppressed, while when the system incorporates benzene guest molecules, the movements of the system are even more restricted.
authors.affiliation: Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain. jarv@unizar.es
authors.forename: J Alberto
authors.initials: JA
authors.lastname: Rodríguez-Velamazán
authors.forename: Miguel A
authors.initials: MA
authors.lastname: González
authors.forename: José A
authors.initials: JA
authors.lastname: Real
authors.forename: Miguel
authors.initials: M
authors.lastname: Castro
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Muñoz
authors.forename: Ana B
authors.initials: AB
authors.lastname: Gaspar
authors.forename: Ryo
authors.initials: R
authors.lastname: Ohtani
authors.forename: Masaaki
authors.initials: M
authors.lastname: Ohba
authors.forename: Ko
authors.initials: K
authors.lastname: Yoneda
authors.forename: Yuh
authors.initials: Y
authors.lastname: Hijikata
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Yanai
authors.forename: Motohiro
authors.initials: M
authors.lastname: Mizuno
authors.forename: Hideo
authors.initials: H
authors.lastname: Ando
authors.forename: Susumu
authors.initials: S
authors.lastname: Kitagawa