Color- and Morphology-Controlled Self-Assembly of New Electron-Donor-Substituted Aggregation-Induced Emission Compounds

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• 作者：Caixia Niu ; Liu Zhao ; Tao Fang ; Xuebin Deng ; Hui Ma ; Jiaxin Zhang ; Na Na ; Jingsa Han ; Jin Ouyang
• 刊名：Langmuir
• 出版年：2014
• 出版时间：March 11, 2014
• 年：2014
• 卷：30
• 期：9
• 页码：2351-2359
• 全文大小：590K
• 年卷期：v.30,no.9(March 11, 2014)
• ISSN：1520-5827

文摘

Four electron-donor-substituted aggregation-induced emission (AIE) compounds, N,N鈥?bis(4-methoxylsalicylidene)-p-phenylenediamine (BSPD-OMe), N,N鈥?bis(4-methylsalicylidene)-p-phenylenediamine (BSPD-Me), N,N鈥?bis(salicylidene)-p-phenylenediamine (BSPD), and N,N鈥?bis(4-hydroxylsalicylidene)-p-phenylenediamine (BSPD-OH), are designed and synthesized. They are all found to exhibit controlled self-assembly behaviors and good thermal properties. By changing the terminal electron-donor groups, they are controlled to self-assemble into three emission colors (green, yellow, and orange) and four morphologies (microblocks, microparticles, microrods, and nanowires) in THF/water mixtures. Their self-assembled structures were investigated with scanning electron microscopy (SEM), fluorescent microscopy images, transmission electron microscopy (TEM), and powder X-ray diffraction (PXRD) techniques. In addition, the emission colors of BSPD-OH can be successfully controlled to three colors (green 鈫?yellow 鈫?orange) through simply changing the water fraction (f_w). Their thermal gravimetric analysis (TGA) results indicate that their thermal decomposition temperatures (T_d, corresponding to 5% weight loss) range from 282 to 319 掳C. Their differential scanning calorimetry (DSC) data show that BSPD-OH bears a glass-transition temperature (T_g) of 118 掳C. The good T_d and T_g values will ensure them to be luminogens for organic light-emitting diodes (OLEDs). The theoretical calculations and single-crystal X-ray diffraction (XRD) analysis of BSPD-OMe and BSPD suggest that the stronger electron donor substituent can twist the molecular conformation, decrease the degree of 蟺 conjugation, increase the energy gap, and then induce the emission colors鈥?blue shift and morphology variation. The results are meaningful in controlling the emission colors and self-assembly shapes of these derivatives, and they also provide a novel but facile way to get color-tunable AIE luminogens for OLEDs.