title: Reversible Guest Binding in a Non-Porous Fe(II) Coordination Polymer Host Toggles Spin Crossover.
abstract: Formation of either a dimetallic compound or a 1 D coordination polymer of adiponitrile adducts of [Fe(bpte)](2+) (bpte=[1,2-bis(pyridin-2-ylmethyl)thio]ethane) can be controlled by the choice of counteranion. The iron(II) atoms of the bis(adiponitrile)-bridged dimeric complex [Fe2 (bpte)2 (μ2 -(NC(CH2 )4 CN)2 ](SbF6 )4 (2) are low spin at room temperature, as are those in the polymeric adiponitrile-linked acetone solvate polymer {[Fe(bpte)(μ2 -NC(CH2 )4 CN)](BPh4 )2 ⋅Me2 CO} (3⋅Me2 CO). On heating 3⋅Me2 CO to 80 °C, the acetone is abruptly removed with an accompanying purple to dull lavender colour change corresponding to a conversion to a high-spin compound. Cooling reveals that the desolvate 3 shows hysteretic and abrupt spin crossover (SCO) S=0↔S=2 behaviour centred at 205 K. Non-porous 3 can reversibly absorb one equivalent of acetone per iron centre to regenerate the same crystalline phase of 3⋅Me2 CO concurrently reinstating a low-spin state.
authors.affiliation: Current address: Department of Chemistry and Chemical Engineering, Chalmers Univeristy of Technology, 41296 Gothenburg (Sweden).|Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M (Denmark).
authors.forename: Anders
authors.initials: A
authors.lastname: Lennartson
authors.affiliation: School of Chemistry, The University of Sydney, NSW 2006, Sydney (Australia).
authors.forename: Peter
authors.initials: P
authors.lastname: Southon
authors.affiliation: School of Chemistry, The University of Sydney, NSW 2006, Sydney (Australia).
authors.forename: Natasha F
authors.initials: NF
authors.lastname: Sciortino
authors.affiliation: School of Chemistry, The University of Sydney, NSW 2006, Sydney (Australia).
authors.forename: Cameron J
authors.initials: CJ
authors.lastname: Kepert
authors.affiliation: Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby (Denmark).
authors.forename: Cathrine
authors.initials: C
authors.lastname: Frandsen
authors.affiliation: Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby (Denmark).
authors.forename: Steen
authors.initials: S
authors.lastname: Mørup
authors.affiliation: Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen (Denmark).
authors.forename: Stergios
authors.initials: S
authors.lastname: Piligkos
authors.affiliation: Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M (Denmark). mckenzie@sdu.dk.
authors.forename: Christine J
authors.initials: CJ
authors.lastname: McKenzie
keywords: coordination polymers; host-guest systems; iron; sorption; spin crossover