| In recent years, molecular electronic devices (such as molecular field effect tube, molecular rectifier, molecular memory, molecular wire, molecular switch and molecular motor, etc.) as the next generation of electronic devices have been rapid development. Among them, the molecular switch as the basic unit of future logic and storage circuit has attracted much attention. Among the various molecular switch systems, diarylethenes, due to their excellent thermal stability and outstanding fatigue resistance, are one of the most promising photochromic compounds for practical applications. Therefore, it is very significant to develop the diarylethenes with novel structures and unique performances. In this thesis, we systematically studied the substituent effects, solvent effects, acid-base effect and metal complexing effect on the fluorescent and photochromic properties of2-(2-pyridyl) imidazole containing diarylethene derivatives (PI-BTEs). The main research contents are as follows:1. For studying the different substituents on the fluorescent and photochromic performances of2-(2-pyridyl) imidazole containing diarylethene derivatives (PI-BTEs), we designed to synthesize a series of diarylethene compounds L1-L5, and studied the solvent effect of the parent compound L3on the fluorescence and photochromic properties. The results would provide some reference and guidance for us to design novel PI-BTEs compounds according to the requirement in future.2. Because of the acid-base interaction between the alkaline groups (imidazole and pyridine) and the acid, a series of diarylethene derivatives with imidazoles as the ethene bridges (L2, L3, L6and L7) are prepared to investigate the influence on their absorption spectra, fluorescence spectra and thermal stability by the acid. It has been demonstrated that not only switch of the diarylethene derivatives between P-type and T-type photochromism by the acid stimuli (this photochromic compound has a potential application in rewritable papers of write-by light/erase-by-heat systems) is achieved, but also the reversible acid induced gating "lock" regulation by adjusting the quantity of acid is accomplished. The strong acid plays a gated "lock" role and the alkaline triethylamine may act as the "key" role in this process. Such gating photochromism has potential applications in nondestructive readout.3. By chelating metallic subunits with2-(2-pyridyl) imidazole, we designed to synthesize the platinum complexes of L2-Pt and L4-Pt. The results show that L2-Pt complex exhibits not only the near-infrared photochromism but also the turn-on fluorescence. To the best of our knowledge, this is the first turn-on fluorescence and near-infrared photochromism of metal diarylethene molecular switch, which has potential applications in the high resolution fluorescence imaging and biological fluorescence label. |
