Construction And Study Of Luminescent Materials Based On Cyanostilbene Chromophores

Photochromic materials are a class of materials whose fluorescent color can change significantly under the stimulation of light,and have promising applications in fields such as optical switches.Among them,cyanostilbene is one of the typical photochromic materials due to its unique optical properties.Through reasonable chemical modifications,different functions can be conferred,which have important scientific significance and application value.In this thesis,a series of α-cyanostilbene derivatives with different cores as well as side chains were synthesized by selecting benzaldehyde derivatives and phenylacetonitrile derivatives as the main raw materials.Firstly,cyanostilbene derivatives CA1 and CA2 with spirobifluorene as the core were synthesized,and their luminescence properties were investigated by absorption spectrum,emission spectrum,nuclear magnetic hydrogen spectrum and infrared spectrum.The results showed that CA1 and CA2 have typical aggregation-induced emission properties,and both can exhibit force-stimulated responsive color change under the action of mechanical forces.In addition,CA1 and CA2 have different photoresponsive mechanisms and properties in the solution state and the aggregated state: the fluorescence change is dominated by E/Z isomerization in solution,while the fluorescence change is dominated by [2+2] cycloaddition in the aggregated state.In addition,cyanostilbene derivatives TPE-4DCS-1 and TPE-4DCS-12 with a tetraphenylethylene core were synthesized,and the photophysical properties of the samples were investigated by absorption spectroscopy as well as emission spectroscopy,and their photochemical properties were examined by emission spectroscopy,infrared spectroscopy,and nuclear magnetic hydrogen spectroscopy,and the phase behavior of the samples and the photochemical processes in different aggregation states were also investigated using differential scanning calorimetry and polarized light microscopy.The experimental results show that TPE-4DCS-1 and TPE-4DCS-12 have aggregation-induced luminescence properties similar to those of CAs,and TPE-4DCS-12 can achieve reversible photodimerization reactions.In addition,TPE-4DCS-12 molecule with long alkyl chain substituents does not exhibit force-changing properties;however,the maximum emission wavelength of TPE-4DCS-1 is blue-shifted by 20 nm after grinding,and its emission wavelength can be restored to near the initial emission wavelength by fumigation with organoleptic solvents,which has reversible force-chromic properties.