Effects of Molecular Structure on Phase Transitions of Ionic Plastic Crystals Containing Cationic Sandwich Complexes
Effects of Molecular Structure on Phase Transitions of Ionic Plastic Crystals Containing Cationic Sandwich Complexes
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DOI：
10.1021/acs.cgd.8b01390
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发表时间：
2018-12-01
影响因子：
3.8
通讯作者：
Mochida, Tomoyuki
中科院分区：
文献类型：
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作者：
Kimata, Hironori;Mochida, Tomoyuki
夹心配合物的盐在高温下通常表现出塑性相。为了确定可以在较低温度下实现塑性相的分子设计，我们合成了具有各种阴离子（X =单碳-闭合-十二硼酸根（CB 11 H12-：）、B（CN）（4）（-）、CF 3BF 3-、OTf（-）、BF 4-、C（CN）（3）（-）和三（五氟乙基）三氟磷酸根（FAP（-））的[CoCp 2][X]和[Ru（Cp）（C6 H6）][X]（Cp = C5 H5），并研究了它们的相行为。除了C（CN）（3）和FAP盐外，所有的盐都表现出塑性相。随着阴离子尺寸的减小，到塑性相的相变温度趋于降低。这种趋势与在八甲基和十甲基二茂铁盐中观察到的相反。虽然大多数盐的相变温度都很高，但[CoCp 2] [CF 3BF 3]、[Ru（Cp）（C6 H6）][CF 3BF 3]和[Ru（Cp）（C6 H6）][BF 4]的相变温度低于300 K。盐的塑性相具有CsCl型结构。低温下的晶体结构测定表明，大多数盐中的阳离子和阴离子交替排列。然而，C（CN）（3）盐显示出阳离子的堆叠排列，这是不存在塑性相的原因。
Salts of sandwich complexes often exhibit a plastic phase at high temperatures. To determine a molecular design that can achieve a plastic phase at lower temperatures, we synthesized [CoCp2][X] and [Ru(Cp)(C6H6)][X] (Cp = C5H5) with various anions (X = monocarba-closo-dodecaborate (CB11H12-:), B(CN)(4)(-), CF3BF3-, OTf (-), BF4-, C(CN)(3)(-), and tris(pentafluoroethyl)trifluorophosphate (FAP(-))) and investigated their phase behaviors. All of the salts except the C(CN)(3) and FAP salts exhibited a plastic phase. The phase transition temperature to the plastic phase tended to decrease with decreasing anion size. This tendency contrasts that observed in octamethyl- and decamethylferrocenium salts. Although the phase transition temperatures of most salts were high, those of [CoCp2] [CF3BF3], [Ru(Cp)(C6H6)][CF3BF3], and [Ru(Cp)(C6H6)][BF4] were below 300 K. The plastic phases of the salts had a CsCl-type structure. Crystal structure determinations at low temperatures revealed that the cations and anions were arranged alternately in most of the salts. However, the C(CN)(3) salts exhibited a stacking arrangement of the cations, which is responsible for the absence of a plastic phase.