马来二腈基二硫烯镍(Ⅱ)配合物展现了介电反常和弛豫 |
A Bis(maleonitriledithiolato)nickelate Ion-Pair Compound Exhibiting Dielectric Anomaly and Relaxation |
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摘要: 合成并用X-射线单晶衍射表征了一个离子对化合物1,7-bis(1-methylimidazolium)heptane bis(maleonitriodithiolato)nickelate (1)的结构.沿着晶体学c轴方向, 化合物1中的阴、阳离子分别排列形成波浪形的链.变温介电性质研究表明, 化合物1在90 ℃ 左右展现了介电态转变.我们将此转变归于化合物1中平衡阳离子的有序到无序转变.在低频区, 化合物1出现了明显的介电弛豫过程, 这与阳离子偶极运动有关.此外, DSC研究表明, 在第二个升温过程中, 化合物1在66 ℃ 和130 ℃ 左右出现两步冷结晶.此种冷结晶现象在小分子化合物中很罕见, 这与化合物1的较大粘度以及测试过程中的较快降温速率有关. |
关键词: 金属二硫烯配合物 介电反常 介电弛豫 晶体结构 |
基金项目: 国家自然科学基金(No.21201103,21301093)资助项目. |
Abstract: An ion-pair compound, 1,7-bis(1-methylimidazolium)heptane bis(maleonitriodithiolato)nickelate (1), was synthesized and single crystal structurally characterized. The bis(maleonitriodithiolato)nickelate anions and dication formed the wave-shape anion chain along c-axis direction, respectively. 1 undergoes a tunable transition at about 90 ℃ between high and low dielectric states at variable temperature, which probably arises from the order-to-disorder transformation of alkyl chains. The dielectric relaxation process in low-frequency region, attributed to the orientation polarization of the molecules dipoles, was observed and discussed. Furthermore, 1 exhibits cold crystallization around 66 ℃ and 130 ℃ during the second heating scan, and originated from fast cooling rate and the large viscosity. Such study provides a possible strategy to explore switchable dielectric material. CCDC: 1015809. |
Keywords: Metal-bis-dithiolene complex dielectric anomaly dielectric relaxation crystal structure |
投稿时间:2014-08-20 修订日期:2014-09-17 |
摘要点击次数: 1512 |
全文下载次数: 1981 |
段海宝,于姗姗,周宏.马来二腈基二硫烯镍(Ⅱ)配合物展现了介电反常和弛豫[J].无机化学学报,2014,30(12):2872-2878. |
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