The Structure And Property Of(2-hydroxyphenyl) Propenone And Their Dirivatives

?-Conjugated organic solid-state emitters have attracted increasing attention in the past decades due to their wide applications in various fields including organic light-emitting diodes(OLEDs),organic solid-state lasers(OSLs),sensors,bio-imaging,etc.To obtain luminescent organic materials,great efforts have been focused on molecular design and structural modification.However,most of the luminescent organic materials suffer from the notorious aggregation-caused quenching(ACQ)effect.Complex structure and laborious substituent modification have been employed in the molecular design to avoid the ACQ effect,which makes the synthesis time-consuming and cost-wasting.Benzene is the basic structural unit to construct a p-conjugated system with luminescent properties.In general,the emissive organic materials contain more than one benzene ring which serves as either a conjugation unit or a substituent.In this sense,the single-benzene molecule is one of the simplest structures of organic emitters.The purpose of this thesis is to design some new small molecular materials with high luminescence efficiency and to develop their photoelectric functions.In this paper,we designed and synthesized two series of small molecular material systems with different luminescent colors.These materials all have high crystalline fluorescence quantum efficiency,which will play an important guiding role in the design of more small molecular materials in the future.In addition,we have also carried out a preliminary exploration of the application of materials.1.In chapter II,we synthesized four different substituents of(2-hydroxyphenyl)propenone derivatives 1–4 by a simple step.Their have non-emissive nature in solution due to their smaller?-conjugate structure.Amorphous films of these compounds show enhanced single peak emission spectrum,with large Stokes shift and secondary fluorescence quantum efficiency and their fluorescence quantum efficiency are 0.17,0.29,0.19 and 0.18 respectively.These phenomena indicate that this kind of single benzene derivatives have aggregation induced emission(AIE)characteristics.All these compounds can readily form highly emissive crystals with?_f in the range of 0.72–0.84,despite the simple molecular structure,indicating that the solids have a crystallization-enhanced emission(CEE)feature.The crystal structure analysis shows that these crystals have the same crystalline and spatial structure.In addition,crystals 1–4 exhibit significant amplified spontaneous emission behavior,and the minimum half peak width is in the range of 5-10 nm,indicating that these crystals can be used as potential laser medium.2.In chapter III,we have prepared a series of pyrazole derivatives 5–8 with a simple ring reaction by the second chapter of(2-hydroxyphenyl)propenone derivatives.The fluorescence of compounds 5–8 in solution exhibit dual-band emission spectra which from enol and keto structure respectively.The crystalline solids of 5–7 show intense single-band blue emissions,while compound 8 is almost no fluorescence.Crystal structure analysis shows that crystals 5–7 have the same space group and crystal system,but crystal 8 shows a totally different molecular structure compared with 5–7.Through theoretical calculation and crystal structure analysis,we can see that crystal 8 can complete the transformation between conformational A and conformational B,while crystal 5–7 cannot accomplish this process.Based on the isomerization of two reversible covariant structures,a high contrast fluorescent switch is realized.In addition,the reversible luminescence chromism of compound 4 suggests the potential application of this material in sensors or memory devices.In summary,we have designed and synthesized two organic light-emitting materials with simple structure and high crystalline fluorescence quantum yield.Through in-depth study of crystal structure and luminescent behavior,we clearly reveal the relationship between molecular structure and luminescent properties.Indeed,we develop the function of materials,which provides a design strategy for future efficient preparation of high-performance organic light-emitting materials.