title: Counterion effect on the spin-transition properties of the cation [Fe(btzx)3]2+ (btzx=m-Xylylenebis(tetrazole)).
abstract: The influence of the counteranion on the structure and the spin-transition properties of original 1D bis(tetrazole) Fe(II) systems, namely [Fe(btzx)(3)]X(2) (X=PF(6) (-) (1), CF(3)SO(3) (-) (2) and ClO(4) (-) (3); btzx=m-xylylenebis(tetrazole)) is studied. The X-ray crystal structures of compounds 1 and 2 are described in detail. These structures present a solvent molecule encapsulated within pockets formed by btzx ligands along the 1D coordination chains. Compound 2 is shown to be the first structurally characterised alternating HS-LS 1D spin-transition system (HS=high spin, LS=low spin). The magnetic susceptibility measurements of all three compounds are compared. The degree of completion and the transition temperature are both drastically influenced by the counterion used, while surprisingly, the cooperative nature of the transition is not affected by the choice of counterion. Compounds 1 and 2 are further studied by Mössbauer spectroscopy and their distinct LIESST properties are compared.
authors.affiliation: Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Leiden, The Netherlands.
authors.forename: Manuel
authors.initials: M
authors.lastname: Quesada
authors.forename: Ferry
authors.initials: F
authors.lastname: Prins
authors.forename: Eckhard
authors.initials: E
authors.lastname: Bill
authors.forename: Huub
authors.initials: H
authors.lastname: Kooijman
authors.forename: Patrick
authors.initials: P
authors.lastname: Gamez
authors.forename: Olivier
authors.initials: O
authors.lastname: Roubeau
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Spek
authors.forename: Jaap G
authors.initials: JG
authors.lastname: Haasnoot
authors.forename: Jan
authors.initials: J
authors.lastname: Reedijk
mesh_terms: D002412:Cations; D005290:Ferric Compounds / Q000737:chemistry*; D008280:Magnetics; D008958:Models, Molecular; D015204:Spectroscopy, Mossbauer; D013777:Tetrazoles / Q000737:chemistry*
chemical_list: D002412:Cations; D005290:Ferric Compounds; D013777:Tetrazoles