摘要
采用密度泛函方法在(U)B3LYP/6-3 1+G(d,p)水平上对含咪唑与TEMPO单元的离子液体(TEMPO-IL)及其得失电子后的情况进行理论研究。通过设计氧化还原反应、利用吉布斯自由能变,计算了不同型体组成电对的电势数值,用以阐明型体结构与其属性的关系。结果表明:(1)TEMPO-IL得一个电子后的三线态Triplet-Ⅱ比单线态Singlet-Ⅱ稳定;(2)TEMPO-IL得一个电子的过程明显影响了咪唑端的键长与自然电荷布居:继续得一个电子后,受到明显影响的是自由基端。另一方面,当TEMPO-IL失去一个电子时,仍然是自由基端发生明显变化:(3)TEMPO-IL的正电荷布居在C2上,而非人们通常认为的N3上:(4)计算得到的TEMPO-IL不同型体的氧化还原电对的电势数值分别为-5.51V、-0.32V、4.19V,利用电势数值可对实验中存储装置测得的写电压(-6V)、读电压(-1V)、擦电压(5V)进行合理解释,这些计算结果表明存储装置的读、擦、写电压与TEMPO-IL得失电子的型体结构变化有直接关系。这些计算结果可为开发新型存储材料提供有用的理论参考。
A theoretical study on the properties of the ionic liquid containing imidazole and TEMPO units （TEMPO-IL） and its conformations losing or getting electrons has been carried out using the density functional theory （DFT） at the （U）B3LYP/6-31 ＋G（d,p） level. Moreover, based on designing the redox-reactions and applying the Gibbs free-energy change, the electric potentials for the three-confignrations pairs were also calculated, and hereby the relation between the configuration and the property was reasonably revealed. The results show the following： （1） The Triplet-II as triplet states is more stable than the Singlet-II as singlet state while TEMPO-IL gets an electron. （2） When TEMPO-IL gets an electron, the bond lengths and natural populations of imidazole head are obviously influenced. However, when it gets two electrons, the configuration of the free radical head is seriously influenced and changed. On the other hand, when TEMPO-IL loses an electron, the greater change happens still on the configuration of the free radical head. （3） The positive charge is mainly populated on C2 not on N3 as usually expected. （4） In particular, the electric potentials of three redox-pairs for TEMPO-IL eunflgnrations have been calculated to be -5.51 V, -0.32 V and 4.19 V, respectively. They can be used to explain the experimental results reported to be the written voltage （-6 V）, the read voltage （-1 V）and the erased voltage （5 V）. It clearly show that the voltages of writing, reading and erasing are closely correlative with the changes of TEMPO-IL configuration during the process of getting or losing electrons. These calculated results can offer some useful theoretical references for developing new memory device.
出处
《计算机与应用化学》
CAS
CSCD
北大核心
2014年第3期293-297,共5页
Computers and Applied Chemistry
基金
广东省自然科学基金(S2011040000131)
仲恺农业工程学院科研基金(G3072708)
关键词
密度泛函
TEMPO
离子液体
存储器
电压
the density functional theory （DFT）
TEMPO
ionic liquid
memory device
voltage
