The Systhesis And Optical Properties Of Multi-Stimuli-Responsive D-A Structure Compounds Based On Phenothiazine Center

Multi-stimulus response Fluorescence material is the material when the external conditions change,the fluorescent light color can be changed.In the past few years,a large number of multi-stimulus response materials have been developed,whether applied to basic research areas or practical applications such as sensors,data storage,inspection and memory devices.In particular,?-conjugated organic fluorescent materials with solvated discoloration,photochromic,electrochromic,discoloration,thermochromic and acid-induced discoloration change.When conditions such as solvent,light,current,pressure,temperature and pH are changed,the fluorescent light color will change,which attracted the attention of the majority of scientific research workers.But so far,only a few molecules in the solution state and powder state at the same time show more stimulating response characteristics.Recently,the mechanical force-induced fluorescent discoloration material has been extensively explored and studied due to the reversible stimulus response in the solid state.This kind of material under the action of mechanical stress fluorescence color change occurs,this fluorescence discoloration can also be solvent fumigation or heat treatment and other methods to restore to the original state.It is found that the spatial geometrical structure of the organic fluorescent molecules is critical to the discoloration of the material,and the structural characteristics of this molecule are of great significance to the design of the piezoresistive materials.Phenothiazine has a certain twisted skeleton,with a very unique geometric configuration.Therefore,the work of phenothiazine as the center,oxadiazole as the end of the design of a series of D-A structure of the multi-stimulated response fluorescence molecules:1.The fluorescent molecule TPPO of the trigonal D-A structure was synthesized by bonding the oxadiazole groups at the 3,7,10 position of phenothiazine.The photophysical properties,thermal properties and solvated fluorescence discoloration properties of TPPO molecules were studied.And TPPO solid powder has undergone mechanical cycling,heat treatment,milling and dichloromethane solvent fumigation.After a cycle test,we found that TPPO has the characteristics of mechanochromic luminescence,the emission peak has a blue shift and can be recovered by the fumigation of the solvent to the initial state of the fluorescent light color.The XRD was used to characterize the TPPO solid powder before and after rolling,and the reason of the fluorescence discoloration was explored.This work has provided a new idea for the future development of phenothiazine as the central pressure-induced fluorescence discoloration.2.In order to further explore the mechanofluorochromic law of D-A fluorescent molecules,phenothiazine as the core,4-(5-(4-bromophenyl)-1,3,4-oxadiazol-2-yl)benzonitrile as group,the compounds SCN and DCN were designed and synthesized.The influence of symmetry and electron-withdrawing ability on the optical properties of the composites was investigated.SCN and DCN had aggregation-induced luminescence phenomena.SCN and DCN were weakly lit in the pure solution state,but the fluorescence emission intensity was significantly enhanced with the addition of water.SCN and DCN have the characteristics of fluorescence discoloration.After the SCN and DCN solid powders are crushed,the peak emission of the fluorescence emission is redshift.The range of the color change of the asymmetric structure of SCN is stronger than that of symmetry DCN.These work provide invaluable experience in our study of phenothiazine derivatives.