Supramolecular cations of the m-fluoroanilinium(dibenzo[18]crown-6) in ferromagnetic salt
Supramolecular cations of the m-fluoroanilinium(dibenzo[18]crown-6) in ferromagnetic salt
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铁磁盐中间氟苯铵(二苯并[18]冠-6)的超分子阳离子
DOI：
10.1039/c0dt01140a
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
Takayoshi Nakamura
中科院分区：
文献类型：
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作者：
Toru Endo;Tomoyuki Akutagawa;Shin-ichiro Noro;Takayoshi Nakamura
在铁磁性[MnCr（草酸盐）3]-盐中引入超分子阳离子（m-FAni+）（DB[18]冠-6）作为抗衡阳离子，其中m-FAni+和DB[18]冠-6分别表示间氟苯胺鎓 +和二苯并[18]冠-6，其是在（m-FAni+）（DB[18]冠-6）[Ni（dmit）2]-铁电晶体中旋转的极性单元。（m-FAni+）（DB[18]crown-6）[MnCr（oxalate）3]−（CH 3OH）（CH 3CN）（1）的晶体结构由[MnCr（oxalate）3]−和（m-FAni+）（DB[18]crown-6）超分子阳离子的二维蜂窝层交替构成。阴离子层是由MnII和CrIII离子与S = 5/2和S = 3/2自旋，分别由草酸根阴离子，这显示铁磁有序在5.5 K桥接。超分子结构通过m-FAni+阳离子的铵氢原子与DB[18]冠-6空腔的氧原子之间形成氢键而形成。在我们的X-射线结构分析中没有观察到氟原子的取向无序，这表明在盐中没有发生m-FAni+阳离子的双重翻转运动。盐中m-FAni+阳离子的旋转自由度受到相邻DB[18]冠-6分子的空间位阻的限制。基于超分子阳离子在晶胞中所占的体积，讨论了盐中旋转的设计策略。
A supramolecular cation of (m-FAni+)(DB[18]crown-6), where m-FAni+ and DB[18]crown-6 denote m-fluoroanilinium+ and dibenzo[18]crown-6, respectively, which is the polar unit rotating in the ferroelectric crystal of (m-FAni+)(DB[18]crown-6)[Ni(dmit)2]−, was introduced into a ferromagnetic [MnCr(oxalate)3]− salt as the counter cation. The crystal structure of (m-FAni+)(DB[18]crown-6)[MnCr(oxalate)3]−(CH3OH)(CH3CN) (1) is constructed from alternating layers of a two-dimensional honeycomb layer of [MnCr(oxalate)3]− and (m-FAni+)(DB[18]crown-6) supramolecular cations. The anionic layer is composed of MnII and CrIII ions with S = 5/2 and S = 3/2 spins, respectively, bridged by the oxalate anions, which show ferromagnetic ordering at 5.5 K. The supramolecular structure is formed through the formation of hydrogen bonds between the ammonium hydrogen atoms of the m-FAni+ cations and the oxygen atoms of the DB[18]crown-6 cavity. No orientational disorder of the fluorine atoms was observed in our X-ray structural analysis, suggesting that a two-fold flip-flop motion of the m-FAni+ cations does not occur in the salt. The rotational freedom of the m-FAni+ cations in the salt is restricted by the steric hindrance from neighbouring DB[18]crown-6 molecules. A design strategy for the rotation in a salt is discussed, based on the volume that the supramolecular cations occupy in the unit cell.