Studies On The Construction And Properties Of New Photochemical Metal Ion Sensors Based On Hydroxyl-containing Diarylethenes

Due to the excellent photochromism, thermal stability, and fatigue resistance, diarylethenes were well recognized for their potential applications in high density data storage. In recent years, multi-controllable fluorescent switches and photochemical sensors of diarylethene-based have attracted a lot of attention from the research communities. The newly introduced functions will further promote the development of diarylethenes, and point out new directions for the research on diarylethenes. Currently, the development of diarylethene-based photochemical sensors has been a new research hotspot. Therefore, design and synthesis of diarylethenes that are responsive for metal ions are being extensively investigated.In this thesis, the metal ions-recognizing groups were attached to the OH-containing diarylethenes via rational design, to construct the diarylethene derivatives that are multi-cotrollable and responsive to metal ions. The photophysical and photochemical properties of these diarylethenes including multi-controlled fluorescent switching, fluorescent and colorimetric ion sensing, and logic circuit construction were studied with emphasis. The main contents and results are summarized as follows:In chapter 1, research progress of photochemical sensors, especially the research status of diarylethene-based sensors was also reviewed. The aim and significant of the thesis were indicated.In chapter 2, a new photochromic diarylethene with a salicylaldehyde group was designed and synthesized. Its multi-responsive photochromic properties were sysmetically studied with the stimulation of acid/base and light. The results indicated that the diarylethene showed excellent photochromic properties. After deprotonation, the absorption of the closed-ring isomer red shifted by 100 nm, and the fluorescence modulation efficiency increased from 30% to 55%.In chapter 3, a new unsymmetrical photochromic diarylethene with a di-2-picolylamine unit was designed and synthesized. The photoreactivity and its interactions with Zn²⁺ were studied systematically. The results indicated that it exhibited favorable photochromism in both solution and crystalline phase. The interactions between the di-2-picolylamine and Zn²⁺ caused a 2-fold enhancement in its fluorescence intensity, accompanied by an evident fluorescent color change from dark to bright blue. The results revealed that this photochromic diarylethene could act as a fluorescence sensor for Zn²⁺.In chapter 4, a di-2-picolylamine was introdued to the diarylethene with a phenol unit via the Mannich reaction. Its photochromism and interaction with metal ions were systematically investigated. The results indicated that the maximum absorption wavelength of the closed-ring isomer shifted from 558 nm to 504 nm, accompanied by significantly color change from purple to red upon complexing with Cu²⁺. The titration experiment showed that the diarylethene could serve as a colorimetic sensor for Cu²⁺.In chapter 5, a novel diarylethene with an 8-aminoquinoline unit was synthesized via a Shiff base unit. Its multi-addressable behaviors induced by light and chemical stimuli were investigated systematically. The compound was highly sensitive and selective to Mg²⁺ and Ca²⁺ with emission and absorption changes, indicating it could serve as a dual-channel sensor for Mg²⁺ and Ca²⁺. Moreover, on the basis of the multi-controllable characteristics of the diarylethene, a combinational logic circuit was constructed on a single molecule platform.In chapter 6, conclusions and prospectives are presented.