Study On The Synthesis And Optical Properties Of N-(1-pyrene) Imide Compounds

Organic optoelectronic materials have enormous potential applications in the semiconductor field.Pyrene has excellent optical properties which is an ideal organic photoelectric material.However,due to the large planar structure of the pyrene,?-?accumulation is prone to occur,resulting in aggregation-induced quenching in the solid state,which limits its application in the field of luminescent materials.In this paper,based on the luminescent properties of pyrene,we have inserted a maleimide group on the pyrene ring to synthesize a series of compounds with a twisted structure,which inhibits ? aggregation in the ruthenium solid state.The spectral properties of the compounds were studied,and the relationship between their spectral properties and molecular structure was explored.The pyrene-imide was used as a fluorescent probe to identify butadiene and anthracene.The main research contents are as follows:1.By introducing maleimide onto the pyrene,the pyrene-imide PM is obtained,which is no fluorescence in both the solution state and the solid state.It is found by theoretical calculation that the HOMO orbitals of the compound PM are substantially distributed on the pyrene,while the LUMO orbitals are distributed on the maleimide group.It is proved that the PET effect exists in the compound PM.Using PM as a fluorescent probe to identify butadiene and anthracene respectively.The fluorescence titration,reaction time and selective identification indicate that probe PM has high sensitivity and specificity in identifying butadiene and anthracene under different environments.2.In order to prevent the PET effect between the pyrene and the maleimide,restore the fluorescence of pyrene,we cycloaddition of the pyrene-imide with the conjugated olefin and the anthracene derivative to obtain two series of compounds PM1,PM2,PM3 and PM4,PM5,PM6.The UV absorption and fluorescence emission of the two series of compounds in the solution state are basically the same,but there are large differences in the solid state,especially PM2 and PM4,which have a large red shift relative to the fluorescence emission of other compounds in the solid state.It is proved by aggregation induction and concentration dependence that PM2 and PM4 emit excimer fluorescence in the solid state,while the other four compounds emit monomer fluorescence in the solid state.Therefore,PM2 and PM4 have a large red shift in fluorescence in the solid state relative to the other four compounds.3.In order to prove from the spatial structure that the six compounds emitdifferent fluorescence in the solid state,that is,the fluorescence of the monomer fluorescence and the excimer,we obtained the crystal structurethe of PM1 and PM4,which emit monomer and excimer fluorescence in the solid state respectively.Due to the loose accumulation of PM1,there is a large degree of slip between the two parallel pyrene rings,there is almost no overlap,and the ?-? action is weak,which showing the filling mode of the monomer.Therefore PM1 emits monome fluorescence in the solid state.However,the pyrene molecules of PM4 has a large overlap,and the ?-? interaction is strong.It is easy to form dimers in the aggregate state.These dimers form a stable excimer rigid geometry and emit excimer fluorescence.4.The molecular packing mode of six compounds in the original solid state affects its mechanochromism property.Since PM1,PM3,PM5,and PM6 are stacked in a single state in the original state,there are voids or interface layers in the stacked structure.Under the action of external force,the stacked structure is easily broken,the packing becomes tight,the planarity is stronger,and the ?-? conjugation effect between molecules is enhanced.Thereby,the loose monomer molecular arrangement is converted into a highly overlapping dimer,which eventually leads to a red shift of the fluorescence emission,emits excimer fluorescence.Thus compounds arranged in a monomer have mechanochromism properties.However,the overlap of pyrene groups in the compounds PM2 and PM4 is very high,the crystals are densely packed,and the voids in the stacked structure are small,which arranged in dimers.Due to their stable molecular packing,the external stimulus of grinding and fumigation has little effect on its molecular packing,both of which show excimer molecule emission.Thus the compounds arranged in dimers do not have mechanochromism properties.There are 54 figures,4 tables and 99 references in this paper.