The Synthesis And Research Of Piezochromic Based On Benzoyl Hydrazone Group

Piezochromic(machanochromic)luminescent materials are a class of “ smart ”materials with luminescent properties that change in response to external force stimuli.These materials are widely used in many fields such as mechanosensors,memory chips,security inks and optoelectronic devices,and have attracted considerable interest in recent years.Until now,the piezochromic luminescent materials that are dependent on changes in physical molecular packing modes are dye-doped polymers,metal ion complexes and organic micro-molecular compound.In this paper,we synthetized a series of groups containing acylhydrazone fluorescent compounds and discussed the relationship between their molecular structure and photophysical properties.In this paper,eight groups containing acylhydrazone coumarin compounds with different functional groups have been designed and synthesized,and photophysical properties of the target compounds and piezallochromy have been measured.These eight functional groups are methoxy,-Br,trifluoromethyl,hydrogen,methyl,N,N'-dimethyl,tert-butyl and hydroxy.Study indicates that,red-shift of emissions can be observed as the concentration increased,which tert-butyl is red shifted 90 nm.According to crystal structure and quantum chemistry of the compounds of R1,therefore,a conclusion can be made that the forming of intermolecular hydrogen bonds induces the form of J-aggregates by self-assembly.Then,due to the increase in ?-? interaction among different molecules,the emission peaks of red-shifted appeared.Compared with the compounds of R1,we could see that the red-shifted of the fluorescence emission spectra have some slight changes with different functional groups at the same condition.Apart from the above,We have also studied the piezallochromy propertiy of those compounds in the solid state.Those material which demonstrate piezallochromy propertiy except the compounds of R6 and R8.By the X-ray and DSC we found that,the mechanism of piezallochromy is contributed to the transformation between crystalline and amorphous.Compounds R1,R3 and R7 can be smartly switched in the fluorescence emission by various external stimuli such as grinding,annealing and solvent-filming.Containing benzoylhydrazone coumarin compounds are widely used in many fields such as autotype material,secret ink and mechanosensors.