Synthesis, Crystal Structure, Polymorphism, and Magnetism of Eu(CN3H4)2 and First Evidence of EuC(NH)3
Synthesis, Crystal Structure, Polymorphism, and Magnetism of Eu(CN3H4)2 and First Evidence of EuC(NH)3
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DOI：
10.3390/inorganics5010010
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发表时间：
2017-03-01
期刊：
影响因子：
2.9
通讯作者：
Dronskowski, Richard
中科院分区：
文献类型：
--
作者：
Goerne, Arno L.;George, Janine;Dronskowski, Richard
我们报道了第一个磁耦合胍，-Eu(CN3H4)(2)（单斜晶系，P2(1)，a = 5.8494(3)埃，b = 14.0007(8)埃，c = 8.4887(4)埃，= 91.075(6)度，V = 695.07(6)埃(3)，Z = 4)。其合成、多晶型、晶体结构和性质均得到密度泛函理论（DFT）计算的补充和支持。 Eu(CN3H4)(2) 的 -、- 和 - 多晶型物在粉末 XRD 中有所不同，而 - 相随着时间的推移转变为 - 形式。在-Eu(CN3H4)(2)中，Eu是八面体配位的并且位于一维链中；胍酸根阴离子显示出氢键网络。理论上预测不同的胍酸根阴离子将采用顺式、反式和全反式构象。磁测量证明了铁磁相互作用，推测是沿着铕链。最后，引入EuC(NH)(3)（与SrC(NH)(3)和YbC(NH)(3)同构，六方晶系，P6(3)/m，a = 5.1634(7)埃，c = 7.1993(9)埃，V = 166.23(4)埃(3)，Z = 2）作为可能的铁磁体。
We report the first magnetically coupled guanidinate, -Eu(CN3H4)(2) (monoclinic, P2(1), a = 5.8494(3) angstrom, b = 14.0007(8) angstrom, c = 8.4887(4) angstrom, = 91.075(6)degrees, V = 695.07(6) angstrom(3), Z = 4). Its synthesis, polymorphism, crystal structure, and properties are complemented and supported by density-functional theory (DFT) calculations. The -, - and -polymorphs of Eu(CN3H4)(2) differ in powder XRD, while the -phase transforms into the -form over time. In -Eu(CN3H4)(2), Eu is octahedrally coordinated and sits in one-dimensional chains; the guanidinate anions show a hydrogen-bonding network. The different guanidinate anions are theoretically predicted to adopt syn-, anti- and all-trans-conformations. Magnetic measurements evidence ferromagnetic interactions, presumably along the Eu chains. Finally, EuC(NH)(3) (isostructural to SrC(NH)(3) and YbC(NH)(3), hexagonal, P6(3)/m, a = 5.1634(7) angstrom, c = 7.1993(9) angstrom, V = 166.23(4) angstrom(3), Z = 2) is introduced as a possible ferromagnet.