title: Influence of HF2- geometry on magnetic interactions elucidated from polymorphs of the metal-organic framework [Ni(HF2)(pyz)2]PF6 (pyz = pyrazine).
abstract: A tetragonal polymorph of [Ni(HF(2))(pyz)(2)]PF(6) (designated β) is isomorphic to its SbF(6)-congener at 295 K and features linear Ni-FHF-Ni pillars. Enhancements in the spin exchange (J(FHF) = 7.7 K), Néel temperature (T(N) = 7 K), and critical field (B(c) = 24 T) were found relative to monoclinic α-PF(6). DFT reveals that the HF(2)(-) bridges are significantly better mediators of magnetic exchange than pyz (J(pyz)), where J(FHF) ≈ 3J(pyz), thus leading to quasi-1D behavior. Spin density resides on all atoms of the HF(2)(-) bridge whereas N-donor atoms of the pyz ring bear most of the density.
authors.affiliation: Department of Chemistry and Biochemistry, Eastern Washington University, 226 Science, Cheney, WA 99004, USA. jmanson@ewu.edu
authors.forename: Jamie L
authors.initials: JL
authors.lastname: Manson
authors.forename: Kimberly E
authors.initials: KE
authors.lastname: Carreiro
authors.forename: Saul H
authors.initials: SH
authors.lastname: Lapidus
authors.forename: Peter W
authors.initials: PW
authors.lastname: Stephens
authors.forename: Paul A
authors.initials: PA
authors.lastname: Goddard
authors.forename: Rico E
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authors.lastname: Del Sesto
authors.forename: Jesper
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authors.lastname: Bendix
authors.forename: Saman
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authors.lastname: Ghannadzadeh
authors.forename: Isabel
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authors.lastname: Franke
authors.forename: John
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authors.lastname: Singleton
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authors.lastname: Lancaster
authors.forename: Johannes S
authors.initials: JS
authors.lastname: Möller
authors.forename: Peter J
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authors.lastname: Baker
authors.forename: Francis L
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authors.lastname: Pratt
authors.forename: Stephen J
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authors.lastname: Blundell
authors.forename: Jinhee
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authors.lastname: Kang
authors.forename: Changhoon
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authors.lastname: Lee
authors.forename: Myung-Hwan
authors.initials: MH
authors.lastname: Whangbo