新型Zn^(2+)基金属有机框架结构的温度依赖的导电、发光性能及理论计算(英文)  

Temperature-Dependent Conductivity,Luminescence and Theoretical Calculations of a Novel Zn(Ⅱ)-Based Metal-Organic Framework

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作  者:高义粉 庄桂林[1] 柏家奇 钟兴[1] 王建国[1] 

机构地区:[1]浙江工业大学化学工程学院,杭州310032

出  处:《物理化学学报》2017年第1期242-248,共7页Acta Physico-Chimica Sinica

基  金:supported by the National Key Basic Research Program of China(973)(2013CB733501);National Natural Science Foundation of China(21176221,21136001,21671172,21306169,91334013)~~

摘  要:通过Zn^(2+)和1,3,5-三苯甲酸(H_3BTB)配体反应获得一种新型的四重互穿的金属有机框架结构(MOF)1。单晶体结构分析表明这是一种由中性N,N-二甲基甲酰胺(DMF)分子和H_2NMe_2^+阳离子沿b轴密封于通道的三维(10,3)网状阴离子框架结构。交流阻抗测试显示该结构的导电性能具有特殊温度依赖性。其电导值在20℃下为0.36×10^(-6)S·cm^(-1),随着温度升高导电能力迅速增大,160℃达到最大值2.24×10^(-5)S·cm^(-1),继续升高温度,导电能力开始下降。分子动力学(MD)模拟和介电性质测量表明,这种特殊温度依赖的导电性能是来自于随温度升高H_2NMe_2^+阳离子迁移增强以及DMF挥发的协同效应。0.20 V的传输能垒接近于质子导电性能。研究表明:MOFs孔对H_2NMe_2^+的限制作用是获得电子材料的一种潜在理想方法。同时,在1中发现一种有趣的荧光现象,发射峰位置比在H_3BTB配体中更加蓝移。密度泛函理论(DFT)计算揭示这是由于在1中,配体BTB^(3-)的离域π键结构破坏,禁带宽度增大所致。A novel four-fold interpenetrating metal-organic framework (MOF) (1) was obtained following reaction between Zn^2+ and benzene-1,3,5-tribenzoate (H3BTB). Single crystal analysis demonstrated that the framework featured a three-dimensional (10, 3) net anionic framework with dimethyl formamide (DMF) and H2NMe2^+ encapsulated in channels along the b axis. Alternating current impedance measurements revealed an unusual temperature-dependent conductance. As the temperature was increased from 20℃ the conductance value increased from 0.36 × 10^-6 S·cm^-1 to a maximum value of 2.24 × 10^-5 S·cm^-1 at 160 ℃, and then began to decrease. A combination of molecular dynamics (MD) simulations and dielectric property measurements demonstrated that this conductance behavior could be attributed to the synergic effect of the enhanced mobility of the H2NMe2^+ cation and removal of DMF as the temperature was increased. Furthermore, the transporting energy barrier was determined to be 0.20 eV, which confirmed that the conductance was caused by proton conductivity. This work indicated that the confinement of H2NMe2^+ within the pores of MOFs is a promising method to induce electrical conductivity. Interestingly, the emission peak of I was blue-shifted when compared with that of H3BTB. Density functional theory (DFT) calculations revealed that this phenomenon was caused by the disruption of delocalized π-bonds within the BTB3 ligand in 1.

关 键 词:MOFS 密度泛函理论计算 导电性 冷发光 

分 类 号:O641.4[理学—物理化学]

 

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