Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.
Angew Chem Int Ed Engl. 2016 Feb 5;55(6):2097-100. doi: 10.1002/anie.201510024. Epub 2015 Dec 28.
The compound [CH3 CH2 NH3][Cu(HCOO)3] undergoes a phase transition at 357 K, from a perovskite to a diamond structure, by heating. The backward transition can be driven by pressure at room temperature but not cooling under ambient or lower pressure. The rearrangement of one long copper-formate bond, the switch of bridging-chelating mode of the formate, the alternation of N-H⋅⋅⋅O H-bonds, and the flipping of ethylammonium are involved in the transition. The strong N-H⋅⋅⋅O H-bonding probably locks the metastable diamond phase. The two phases display magnetic and electric orderings of different characters.
化合物 [CH3 CH2 NH3][Cu(HCOO)3] 在 357 K 时通过加热从钙钛矿结构转变为金刚石结构。在室温下，通过加压可以驱动反向转变，但在环境压力或更低压力下冷却则不行。转变涉及到一条长的铜甲酸盐键的重排、甲酸盐桥联螯合模式的切换、N-H···O 氢键的交替以及乙基铵的翻转。强的 N-H···O 氢键可能锁定亚稳的金刚石相。这两种相显示出不同性质的磁有序和电有序。
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