Synthesis And Optical Properties Of Novel Bodipys

Organic luminescent material has been approved as an important tool of scientific research by many scientists around the world because of its excellent performances and develops rapidly in recent years.Organic luminescent material usually has relatively high molar extinction coefficient,could be easily modified and is rich in numbers compared with inorganic luminescent material,therefore this kind of material is widely used in many scientific field,such as chemical analysis,solar energy conversion and.organic light emitting diode(OLED).As a result,it has become a focused subject to develop new organic molecules with good properties.Bodipy has many unique properties because of its charming structure and Bodipy could be easily modified.Almost all the positions around Bodipy framework could be modified to bring different properties for Bodipy.However,Bodipy also has many limitations in practical application,such as the absorption spectra of Bodipy usually limits in 470-530 nm,the Stokes shift of Bodipy is very small so that the emission intensity of this kind compound is reduced by self-abdorption,the aggregation-caused quenching(ACQ)photophysical effect in solid state and so on.These problems limit the practical application of Bodipy,so that,it becomes the key of scientific research to design and synthesis new Bodipy which have improvement in these aspects in recent years.Herein,these kinds of novel Bodipy are designed and synthesized according to the different problem discussed above in practical application,the specific contents as following:(1)Chiral benzo-fused aza-BODIPYs,namely N,N-difluoroboryl-[(dinaphtho[1,2-e:1 ',2'-g]-1,4-dioxocine)-1-[N-(3-phenyl-2H-is oindole-l-yl)methy lene]-3-phenyl-1 H-isoindol-1-ylidene)amine]and N,N-difluoroboryl-[(dinaphtho[1,2-e:1',2'-g]-1,4-dioxocine)-1-[(dinaphtho[1,2-e:1'.2'-g]-1,4-dioxocine)-N-(3-phenyl-2H-isoindole-1-yl)methylene]-3-phenyl-1H-iso indol-1-ylidene)amine],have been synthesized and spectroscopically characterized.Fusion of benzene moieties onto the BODIPY periphery in combination with the introduction of peripheral chiral binaphthyl substituents renders the extension of optical activity of resulting chiral benzo-fused aza-BODIPYs into the near-IR(NIR)range,representing the first chiral BODIPYs with NIR optically activity.For comparative study,N,N-difluoroboryl-[N-(3-phenyl-2H-isoindol-1-yl)-N-(3-phenyl-1H-isoindol-1-yli dene)amine]was also prepared and characterized in a similar manner.(2)A series of three new boron-dipyrromethenes bringing different functionalized triphenylamine donor Bodipy-TPA-R(R = BI,BH-OH,BH-COOH)together with the reference compound Bodipy-TPA,have been synthesized and structurally characterized.Due to their same less electronic coupling between the triphenylamine donor and Bodipy acceptor in ground state and in particular the twisted intramolecular charge transfer(TICT)between them in excited state,these functionalized Bodipy derivatives exhibit similar optical properties in solution but not in the solid state owing to their differently intermolecular interaction and molecular packing associated with the diverse triphenylamine-modification.The lack of effective face-to-face ?-? stacking interaction between Bodipy luminophores in crystalline states of Bodipy-TPA and Bodipy-TPA-BH-COOH,in combination with the restriction of the twisting motion and charge transfer between their triphenylamine moiety and Bodipy framework,results in the obvious aggregation-(AIE)and crystallization-induced emission(CIE)effect,with the absolute fluorescent quantum yield(?)as high as 19.47%and 12.30%for single crystals of Bodipy-TPA and Bodipy-TPA-BH-COOH,respectively.In good contrast,despite the same complete restriction of the functionalized triphenylamine donor around Bodipy acceptor,the presence of partial overlapping face-to-face ?-? interaction between two parallel C9BN2 fluorophores leads to very low 0 being 1.37%and 3.40%for the single crystals of Bodipy-TPA-BI and Bodipy-TPA-BH-OH as well as the negligible AIE effect.Notably,functionalization over triphenylamine moiety with carboxyl-benzoylhydrazone group in Bodipy-TPA-BH-COOH renders this compound a good solid-state fluorescence sensor due to its fast fluorescence ON-OFF response for HCl vapor in thin film.(3)Different number of triphenylamine are connected to the 2,6-positions of Bodipy-TPA to obtain two new compounds Bodipy-2TPA and Bodipy-3TPA.The electronic absorption spectra of these two newly prepared compounds have only slight red-shift compared with the reference compound Bodipy-TPA,however,the fluorescence of these two compounds have significant red-shift in solution.The two Bodipys have large Stocks shift(123 nm and 98 nm in CHCl3)because of the geometry relaxation upon photoexcitation.Meanwhile,connecting triphenylamine to the Bodipys leads to the lack of effective face-to-face ?-?stacking interaction between Bodipy luminophores and the restriction of the twisting motion in crystalline states.As a result,Bodipy-2TPA and Bodipy-3TPA have obvious aggregation-induced emission(AIE)effect and red fluorescence in solid state,with the absolute fluorescent quantum yield(?)as high as 20.54%and 13.84%for single crystals of Bodipy-2TPA and Bodipy-3TPA,respectively.