Synthesis And Properties Of Imidazole-based Diarylethenes With Different Substituents

In recent years, organic optoelectronic materials have absorbed more and more attention. Photochromic materials as one of the most potential applications of organic opoelectronic materials, have been extensively studied due to their simple operation, high resolution capability, reusage and so on. Among the photochromic systems, dithienylethenes because of their excellent thermal stablity, fatigue resistance and fast response were widely used in optical memories, optical storage, optical switches and other fields. Therefore, design and synthesis of novel dithienylethenes and investigations of their properties were of great significance.In this dissertation, the imidazole was introduced into the dithienylethene as a bridge unit. A series of photochromic compounds with different substituents were synthesized and their properties were investigated, especially in exploring the effects of substitution. Details are described in the following:1. A series of dithienylethenes with imidazole as bridge unit were synthesized, and their structures had been well defined by1H NMR,13C NMR, and mass spectrometry.2. Their photochromism were checked by UV/Vis absorption spectra and fluorescence emission spectra in CH3CN (2.0×10-5mol/L) solution. The UV/Vis absorption was different when the position of substituents was changed. N-methylation on the imidazole rings would result in a red-shift of UV/Vis absorption of the closed-isomer and a blue-shift of fluorescence emission of the closed-isomer. In addition, the electronic effect of substituents had great effects on the UV/Vis absorption spectra, electron-donating subsituents could shift the absorption maxima of the closed-ring isomers to a longer wavelength which close to the near infrared region.3. The function of ion-identification were investigated by UV/Vis absorption spectra and fluorescence emission spectra in CH3CN (2.0×10-5mol/L) solution. The results suggested that the electronic effect of substituents had great effects on the ion-identification and the N-H would participate in some ion-identification.