Construction Of New Diketopyrrolopyrrole Derivatives And Study Of Their Stimulation Response Behabior

The multi-stimulus fluorescence response refers to the "smart" material upon different external stimulus to making a corresponding fluorescence change.Because it is more sensitive to temperature,pH,compressive stress,and solvents,so it usually be used in sensors,detectors,and biofluorescence probes and imaging fields.The multi-stimulus fluorescence materials have great application value in practical applications such as information record storages,bioimaging,and security anti-counterfeiting.The diketopyrrolopyrrole derivatives have advantages of excellent light and heat resistance,large two-photon absorption cross section,and high fluorescence efficiency and so on,and have good application prospects in practical applications such as organic solar cells,field effect transistors,bioimaging and mechanofluorochromic.Therefore,a series of multi-stimulus-responsive D(Donor)-A(Acceptor)-type fluorescent molecules were designed and synthesized with DPP as the center.We explored the relationship between structure and properties through the photophysical properties of solution and aggregation states.This method provide ideas and experience for design and synthesis of multi-stimulus response fluorescent materials.1.We designed and synthesized a multi-stimulus-responsive D-A fluorescent molecule ADPP with a twisted structure by using DPP as the electron-withdrawing group(A)and 9-anthracene as the electron-donating group(D).We explored the relationship between molecular structure and performance by physical properties,thermal stability,and nano-aggregation effects of solution and solid state.It was found that ADPP is an piezochromic aggregation-induced enhancement emission materials.ADPP's fluorescence is weak in the solution state,while fluorescence is significantly enhanced with the addition of poor solvent water,and formed nano-aggregation states,indicating that aggregation-induced enhancement emission effect(AEE).Solid powders exhibit different fluorescence characteristics after mechanical stimulation,solvent fumigation,heat treatment,and other external stimuli.It is known that the transformation of mechanofluorochromic properties is attributed to transformation between crystalline and amorphous states through DSC and XRD analysis.2.DPP is selected as electron acceptor(A)group and oxadiazole group as another electron acceptor(A')group to designed and synthesized two novel organic fluorescent molecules CODPP and TODPP with D-A'-?-A-?-A'-D structure compounds by introducing different electron donating groups such as carbazole,triphenylamine.In addition,triphenylamine is a star-type propeller structure which is beneficial to reduce the ?-? stacking between molecules,which makes TODPP exhibit aggregation-induced enhancement emission effect.While CODPP exhibits near-infrared fluorescence of 723 nm due to solid-state ?-? stacking.The blue shift to 614 nm after ground and blue shift to the yellow state of 560 nm after further heat treatment,rendering a large mechanofluorohypsochromic shift up to 160 nm,Which exhibit high contrast,multicolour and multichannel switching,and remarkable mechanohypsochromic luminescence are rarely realized.Different states were stable relatively to solvent fumigation.Therefore,the multi-stimulus response behaviors of CODPP and TODPP may have good application prospects in pressure sensing and temperature-sensitive detectors.