Study On The Structure Design,Synthesis And Properties Of The New Optical Functional Organic Molecules

Functional organic optical materials have advantages over inorganic materials in clear structure,various varieties,pure color,high luminous efficiency,wide color range and easy processing.Therefore,they act an important role in optical sensor,organic solid laser,organic light-emitting diode and bio-imaging.The study on molecular design,synthesis and application based on organic optical functional materials is one of the most important research directions in the century.Functional optical materials including stimuli-responsive materials can display multiple response characteristics to a variety of external stimuli such as ultraviolet light,heat treatment,mechanical disturbance,pH changes,H2O,ions and small molecules,etc.,thus possess important application prospect in information recording,storage,marking and anti-counterfeiting.In this paper,we carried out the study on the structure design,synthesis,properties and applications of a series of new optical functional organic molecules,including two bichromophores with a triphenylamine-coumarin dyad structure,two pyrimidine-phthalimide derivatives,six Schiff bases containing salicylaldehyde units and an indoline-spiropyran derivative.The innovative research results have made are as follows:1.Two new bichromophores with TPA-coumarin structure,TC and TF,were designed and synthesized,also characterized by IR,1H NMR,13 C NMR and HRMS.TC and TF showed the different degrees of positive solvatochromism because of their different molecular conformations in various solvents.TC with methyl group and TF with trifluoromethyl group showed a variable red-shifted emission in their solid-state due to their distinctive levels of intramolecular push-pull electronic effect.Thanks to the role of the TPA unit as a propeller-like rotor,TC and TF experienced little ?-?stacking interaction in their condensed phase and therefore exhibited obvious fluorescence emission in the solid-state.The density functional theory calculations indicated that the HOMO and LUMO energy levels of TC and TF were well separated into a TPA unit and coumarin moiety respectively,verifying the status for both TC and TF as D-A compounds in which TPA unit acted as a donor and coumarin moiety as an acceptor.Besides,the bandgap value of TF was a little lower compared with that of TC,indicating its larger delocalization and push-pull effect.Thus,the photophysical properties of these bichromophores with triphenylamine-coumarin dyad structure could be effectively tuned by rational molecular design.2.Two new atypical AIE chromophores PB and NPB were designed and synthesized,also characterized by IR,1H NMR,13C NMR and HRMS.Both PB and NPB showed positive solvatochromism because of their different molecular conformations in various solvents.PB with two methyl groups and NPB with C=C bonds and N,N-dimethylaniline substituting groups showed a variable red-shifted emission in their solid state due to their distinctive levels of intramolecular push-pull electronic effect.Thanks to the twisted structures,PB and NPB experienced little ?-? stacking interaction in their condensed phase and therefore exhibited obvious fluorescence emission in the solid state.The density functional theory calculations indicated that the HOMO and LUMO energy levels of PB and NPB were well separated,verifying the status for both PB and NPB as D-?-A compounds.Besides,the bandgap value of NPB was a little lower compared with that of PB,indicating its larger delocalization and push-pull effect.Moreover,as one would expect,PB and NPB underwent a dramatic color change upon addition of acid as a result of the protonation of the nitrogen atoms.Furthermore,based on the pH-sensitive properties,a dual-output of logic gate was developed successfully.The novel pyrimidine-phthalimide derivatives with sensitive response to pH both in water solution and in the gas phase may hold great potential for applications in the materials science fields.3.Six new AIE chromophores NA-M,NA-F,NA-N,NA-EM,NA-EF and NA-EN were designed and synthesized,also characterized by IR,1H NMR,13 C NMR and HRMS.Thanks to the twisted structures,all the compounds experienced little ?-?stacking interaction in their condensed phase and therefore exhibited obvious fluorescence emission in the solid state.Due to the dual interplaying ESIPT-AIE sensing mechanisms and the the influence of their substituent groups,three compounds showed the pronounced fluorescence enhancement to Mg2+ and thus can distinguish Mg2+ sensitively and selectively.Moreover,the six new AIE chromophores underwent a dramatic color change upon addition of acid as a result of the protonation of the nitrogen atoms upon-N=C-bond.These novel naphthalimide-salicylaldehyde derivatives with sensitive response to Mg2+ and H+may hold great potential for applications in the materials science fields.4.An indoline-spiropyran derivative BNI was designed and synthesized and also characterized by IR,1H NMR,13 C NMR and HRMS.In various organic solvents,BNI exhibited obvious photocolouration and high fatigue-resistance properties due to the reversibly switching between two forms:the colorless ring-close form SP(spiropyran)and the colored ring-open form MC(merocyanine).The MC forms in different solvents lead to a blue shift with increasing solvent polarity,viz.negative solvatochromism,indicating solvent-tunable photochromic behavior and the longer lifetime in polar solvents due to the relatively stable configuration after light irradiation.Based on the property of BNI,a kind of photochromic laminated safety glass was prepared with PVB and photochromic BNI compound,and showed photochromism.The novel compound BNI showed sensitive response to UV light in both various solvents and PVB laminated safety glass,and also can distinguish Fe3+sensitively and selectively,thus may expected to be applied to the photosensitive materials science fields.