Multistimuli-Responsive Benzothiadiazole-Cored Phenylene Vinylene Derivative with Nanoassembly Properties
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- 作者：Chuandong Dou ; Dong Chen ; Javed Iqbal ; Yang Yuan ; Hongyu Zhang ; Yue Wang
- 刊名：Langmuir
- 出版年：2011
- 出版时间：May 17, 2011
- 年：2011
- 卷：27
- 期：10
- 页码：6323-6329
- 全文大小：1001K
- 年卷期：v.27,no.10(May 17, 2011)
- ISSN：1520-5827
文摘
A trifluoromethyl-substituted benzothiadiazole-cored phenylene vinylene fluorophore (1) was synthesized and displayed piezo- and vapochromism and thermo-induced fluorescence variation in solid phase. Grinding could disrupt the crystalline compound 1 with orange emission into amorphous compound 1 with green emission, and heating treatment could change the amorphous compound 1 into crystalline compound 1. Ultraviolet鈭抳isible (UV鈭抳is) absorption spectra, 13C nuclear magnetic resonance (NMR), and powder X-ray diffraction (PXRD) characterizations demonstrated that crystalline and amorphous compound 1 possess different molecular packing. A differential scanning calorimetry (DSC) measurement revealed that the emission switching was due to the exchange between the thermodynamic-stable crystalline and metastable amorphous states. The ground sample exhibited vapochromic fluorescence property. Furthermore, compound 1 showed interesting supramolecular assembly characteristics in solution. Slowly cooling the hot N,N-dimethylformamide (DMF) solution of compound 1 resulted in the formation of orange fluorescent fibers, whereas sonication treatment of the cooling solution led to the generation of organic molecular gel. The field emission scanning electronic microscope (FESEM) and fluorescent microscopy images revealed smooth nano- or microfiber and network morphology properties. The PXRD spectra confirmed that these nano- or microstructures had a similar molecular-packing model with the crystalline state of compound 1. Slow evaporation of the toluene solution of compound 1 could produce green emissive microrods, which exhibited interesting thermo-induced fluorescence variation.