Fakultät für Chemie und Biochemie , Ruhr-Universität Bochum , Universitätsstraße 150 , D-44780 Bochum , Germany.
Leibniz-Institute for Solid State and Materials Research Dresden , Helmholtzstraße 20 , 01069 Dresden , Germany.
Inorg Chem. 2019 Oct 7;58(19):13203-13212. doi: 10.1021/acs.inorgchem.9b02028. Epub 2019 Sep 20.
A set of different open framework iron phosphates have been synthesized ionothermally using a task-specific ionic liquid, 1-butyl-4-methylpyridinium hexafluorophosphate, that acts in the synthesis as the reaction medium and mineralizer: (NH)Fe(HPO)(PO)ClF () and KFe(HPO)(PO)ClF () exhibit similar composition and closely related structural features. Both structures consist of {Fe(HPO)(PO)ClF} macroanions and charge balancing ammonium or potassium cations. Their open framework structure contains layers and chains of corner-linked {Fe(1)OCl} and {Fe(2)FO} octahedra, respectively, interconnected by PO tetrahedra forming 10-ring channels. KFe(POF)F () is built up by {Fe[(POF)F]}{Fe(POF)FF} layers separated by K cations. Chains of alternating {FeFO} and {FeOF} octahedra, which are linear for but undulated for , are linked to each other via corner-sharing {POF} tetrahedra with the fluorine pointing into the interlayer space. The compounds were characterized by means of single crystal and powder X-ray diffraction, infrared spectroscopy, and magnetic measurements. reveals a strong ground state spin anisotropy with a spin 5/2 state and a magnetic moment of 5.3 μ/Fe. Specific heat and magnetic data unveil three magnetic transitions at 95, 50, and 3.6 K. Compound has a very similar crystal structure as compared to but exhibits a different magnetic behavior: a slightly lower magnetic moment of 4.7 μ/Fe and a magnetic transition to a canted antiferromagnetic state below 90 K. Compound exhibits typical paramagnetic behavior close to room-temperature (5.71 μ/Fe). There are no clear indications for a phase transition down to 2 K despite strong antiferromagnetic spin-spin interactions; only a magnetic anomaly appears at 50 K in the zero-field cooled data.
已通过离子热合成方法使用功能化离子液体 1-丁基-4-甲基吡啶六氟磷酸盐合成了一组不同的开放式铁磷酸盐：(NH4)Fe(HPO4)(PO4)ClF()和 KFe(HPO4)(PO4)ClF()具有相似的组成和密切相关的结构特征。这两种结构都由{Fe(HPO4)(PO4)ClF}大分子阴离子和平衡电荷的铵或钾阳离子组成。它们的开放式骨架结构包含由角连接的{Fe(1)OCl}和{Fe(2)FO}八面体层和链，分别由 PO4 四面体连接形成 10 元环通道。KFe(PO4F)F()由{Fe[(PO4F)F]}{Fe(PO4F)FF}层组成，层之间由 K 阳离子隔开。交替的{FeFO}和{FeOF}八面体链通过角共享{POF}四面体相互连接，对于 而言，氟原子指向层间空间。这些化合物通过单晶和粉末 X 射线衍射、红外光谱和磁性测量进行了表征。揭示了一个强的基态自旋各向异性，具有自旋 5/2 态和 5.3 μB/Fe 的磁矩。比热和磁数据揭示了在 95、50 和 3.6 K 时的三个磁转变。与化合物相比，化合物具有非常相似的晶体结构，但表现出不同的磁行为：磁矩略低（4.7 μB/Fe），在 90 K 以下转变为倾斜反铁磁态。化合物在接近室温（5.71 μB/Fe）时表现出典型的顺磁行为。尽管存在强烈的反铁磁自旋-自旋相互作用，但在 2 K 以下没有明显的相转变迹象；在零场冷却数据中仅在 50 K 出现磁异常。
