Effects of structural order on magnetic properties of S = 1 [Ni(HF2)(pyz)2]PF6 (pyz = pyrazine)

We have discovered a third polymorph in the [Ni(HF₂)(pyz)₂]PF₆ family of coordination polymers. As compared to the previously published structures that possess structurally ordered frameworks, a new example features a disordered, monoclinic unit cell. This new variant allows us to examine the effects of structural order and disorder on superexchange pathways, specifically along the Ni-FHF-Ni and Ni-pyz-Ni directions. We consider the local distortions to the Ni(II) coordination sphere and the geometries afforded by the ligands. This presentation will address the possible discrepancies in magnetic properties for these polymorphs as gleaned by examination of their structures.

NSF DMR-1703003 (EWU), DMR-1157490 (MagLab), DoE, FL, ERC, EPSRC.