title: Exploiting Pressure To Induce a "Guest-Blocked" Spin Transition in a Framework Material.
abstract: A new functionalized 1,2,4-triazole ligand, 4-[(E)-2-(5-methyl-2-thienyl)vinyl]-1,2,4-triazole (thiome), was prepared to assess the broad applicability of strategically producing multistep spin transitions in two-dimensional Hofmann-type materials of the type [FeIIPd(CN)4(R-1,2,4-trz)2]·nH2O (R-1,2,4-trz = a 4-functionalized 1,2,4-triazole ligand). A variety of structural and magnetic investigations on the resultant framework material [FeIIPd(CN)4(thiome)2]·2H2O (A·2H2O) reveal that a high-spin (HS) to low-spin (LS) transition is inhibited in A·2H2O due to a combination of guest and ligand steric bulk effects. The water molecules can be reversibly removed with retention of the porous host framework and result in the emergence of an abrupt and hysteretic one-step spin transition due to the removal of guest internal pressure. A spin transition can, furthermore, be induced in A·2H2O (0-0.68 GPa) under hydrostatic pressure, as evidenced by variable-pressure structure and magnetic studies, resulting in a two-step spin transition at ambient temperatures at 0.68 GPa. The presence of a two-step spin crossover (SCO) in A·2H2O under hydrostatic pressure compared to a one-step SCO in A at ambient pressure is discussed in terms of the relative ability of each phase to accommodate mixed HS/LS states according to differing lattice flexibilities.
authors.affiliation: School of Chemistry, The University of Sydney , Sydney, New South Wales 2006, Australia.
authors.forename: Natasha F
authors.initials: NF
authors.lastname: Sciortino
authors.affiliation: School of Chemistry, The University of Sydney , Sydney, New South Wales 2006, Australia.
authors.forename: Florence
authors.initials: F
authors.lastname: Ragon
authors.affiliation: School of Chemistry, The University of Sydney , Sydney, New South Wales 2006, Australia.
authors.forename: Katrina A
authors.initials: KA
authors.lastname: Zenere
authors.affiliation: School of Chemistry, The University of Sydney , Sydney, New South Wales 2006, Australia.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Southon
authors.affiliation: X-ray Science Division, Advanced Photon Source (APS), Argonne National Laboratory , Lemont, Illinois 60439, United States.
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Halder
authors.affiliation: X-ray Science Division, Advanced Photon Source (APS), Argonne National Laboratory , Lemont, Illinois 60439, United States.
authors.forename: Karena W
authors.initials: KW
authors.lastname: Chapman
authors.affiliation: Institut the Ciencia Molecular, Universitat de València , 46980 Paterna, València, Spain.
authors.forename: Lucía
authors.initials: L
authors.lastname: Piñeiro-López
authors.affiliation: Institut the Ciencia Molecular, Universitat de València , 46980 Paterna, València, Spain.
authors.forename: José A
authors.initials: JA
authors.lastname: Real
authors.affiliation: School of Chemistry, The University of Sydney , Sydney, New South Wales 2006, Australia.
authors.forename: Cameron J
authors.initials: CJ
authors.lastname: Kepert
authors.affiliation: School of Chemistry, The University of Sydney , Sydney, New South Wales 2006, Australia.
authors.forename: Suzanne M
authors.initials: SM
authors.lastname: Neville