Department of Chemistry and Biochemistry, Eastern Washington University, 226 Science, Cheney, WA 99004, USA.
Dalton Trans. 2012 Jun 28;41(24):7235-43. doi: 10.1039/c2dt30113j. Epub 2012 May 8.
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.
[Ni(HF(2))(pyz)(2)]PF(6)（标记为β）的四方多晶型物与 SbF(6)同构，在 295 K 时具有线性 Ni-FHF-Ni 支柱。与单斜α-PF(6)相比，自旋交换（J(FHF) = 7.7 K）、尼尔温度（T(N) = 7 K）和临界场（B(c) = 24 T）都得到了增强。DFT 表明，HF(2)(-)桥是比 pyz（J(pyz)）更好的磁交换介质，其中 J(FHF) ≈ 3J(pyz)，从而导致准一维行为。自旋密度存在于 HF(2)(-)桥的所有原子上，而 pyz 环的 N-供体原子承载大部分密度。
