The Design,Preparation And Application Of Intramolecular N-H···O Hydrogen Bonding-Induced Blue-Shifted Luminescent Materials

Under the influence of mechanical force,force-induced luminescent color-changing materials can exhibit corresponding changes in their photophysical properties,making them a new type of stimulus-responsive material with unique and controllable properties.This type of material has a wide range of applications in various fields such as anti-counterfeiting,optical storage device manufacturing,bioimaging,and drug tracing.The transformation of photophysical properties in force-induced luminescence and color-changing materials is influenced by the structural configuration of small molecular stress groups.Control of force-induced luminescence and color change can be achieved through the design of different compound structures.This paper proposes a new design strategy for force-induced luminescence materials that exhibit blue-shifted light,and investigates in-depth their photophysical properties and mechanisms.In this paper,we selected 2,5-dimethoxy-1,4-benzoquinone（DMSS）as the base and synthesized a series of orange-red light-emitting fluorescent small molecules with different forms and chain lengths of amine compounds.We investigated in depth the photo-physical properties and the mechanism of force-induced blue shift,and extended the application based on fluorescent small molecules.The specific details are as follows:1.By introducing benzylamine and naphthylamine substituents onto the main ene ring structure through modification of DMSS,we successfully synthesized three orange-red fluorescent small molecules（BN,1-NN,2-NN）with a benzene-like ene ring structure.Under visible light excitation at 468 nm,the three small molecules BN,1-NN,and 2-NN exhibited optimal fluorescence emission peaks at 598,602 and 612 nm,respectively,with corresponding quantum yields of 12.6%,11.4%and 10.2%.After mechanical grinding,the maximum emission peaks of the three small molecules were located at 566,578 and 585 nm,with corresponding fluorescence quantum yields of6.3%,5.7%and 5.1%.We used a blending method to prepare PMMA-doped thin films of the three samples,and investigated their fluorescence properties in the doped system.2.Flexible chains were introduced into the DMSS body to design and synthesize three highly efficient red fluorescent small molecules（YN,ZBN,YBN）.Under visible light at 468 nm,the optimal emission peaks of YN,ZBN,and YBN fluorescence were620,622 and 626 nm,respectively,with fluorescence quantum efficiencies of 18.3%,19.7%and 20.5%,respectively.After mechanical grinding,the maximum emission peaks were located at 589,597 and 589 nm,with fluorescence quantum efficiencies of 9.2%,9.8%and 10.3%,respectively.By preparing different metal ion solutions of YBN,we found that YBN has unique responsiveness to Mo⁵⁺.We also used ultrasound to prepare YBN nanoparticles and applied them for imaging of Hela cells.3.By replacing the hydroxyl group on DMSS with flexible alkylamines of different chain lengths,a series of red small molecules（YCN,BCN,LCN）were designed and prepared.Under excitation at 470 nm,the optimal emission peaks of YCN,YN,ZBN,and YBN fluorescence were 618,606 and 650 nm,respectively,with fluorescence quantum efficiencies of 15.4%,13.7%and 12.3%,respectively.After mechanical grinding,the maximum emission peaks were located at 608,590 and 610nm,with fluorescence quantum efficiencies of 8.2%,6.8%and 6.1%,respectively.Taking LCN as an example,we investigated its responsiveness to different metal ions and found that LCN has a relatively sensitive response to Ag⁺and Cu²⁺.Using polytetrahydrofuran as a chain extender,and using long-chain isocyanate and triethanolamine as modifiers,LCN was embedded as a stress group to prepare polyurethane films with different mass ratios.The interactions of stress groups in the polymer were studied in depth.