Synthesis And Photophysical Properties Of ?-gelator Based On Nucleosides And Ptridine

In recent years,molecules formed by organic ?-systems have exhibited a wide publicity in the fields of organic light emitting diodes,bioimaging,solar cells,and fluorescence sensing.In particular,organic nanomaterials based on biomolecules such as amino acids,sugars,and nucleosides are attracting attention due to their applications in drug carriers,tissue engineering,and bioimaging.Therefore,the synthesis of self-assembled nanomaterials with fluorescence sensing by combining ?-systems with biomolecules is an effective way to find biomaterials with sensing and photoelectric properties.In this thesis,a series of fluorescence organogelator based on nucleosides or pteridine were synthesized,and their photophysical properties,fluorescence sensing properties,self-assembly capabilities and stimulus responsiveness were systematically studied.The following innovative results were obtained:?1?Carbazole-modified uridine derivatives UC8,UC12 and UC16 were designed and synthesized.Their gelation ability was tested and found that both UC12 and UC16 could form stable organogels in toluene/petroleum.The UV-vis absorption,fluorescence emission and IR spectral changes during the gelation proved that the self-assembly of organogels was driven by H-bonding and ?-? interaction.UC16 could form organogel in different proportion of mixed solvents and presented different gel morphology,which may be the different solubility of compounds in solution.The morphology of the xerogel UC16 obtained from toluene/petroleum?v/v=1/1?displayed tough rod-like microstructures,and obtained from toluene/petroleum?v/v=1/2?displayed 3D networks formed from nanofibers.The results of anion recognition confirmed that UC16 has the ability to recognize fluorine ions,along with the decrease of blue fluorescence intensity of solution and the transition process from gel state to sol state.The cationic selectivity confirmed that UC16 has the ability to recognize mercury and silver ions.?2?A sort ofp-conjugated compounds based on pteridine derivatives were synthesized.To be interesting,compounds FCP,CCP and HCP could self-assemble into organogels in selected organic solvents.The changes in UV-vis absorption and fluorescence emission spectra during gel formation process illustrated that ?-interaction played a crucial role during the gel formation.In addition,different gelation capabilities of the target molecule FCP,CCP and HCP indicated that the halogen atom,especially for the chlorine atom,has a best gelabiliy..In the solvent of amylenealcohol,the CGC?critical gelation concentration?of CCP was 1.5 mg mL^-1.The substitution of 4-pteridine with piperidine,pyrrolidine,ethylamine,benzylamine and hydroxyl to obtain compounds PYP,PIP,DBP,BNP and OHP displayed piezochromic properties.It was worth noting that the PYP and DBP showed the blue-shift of pressure stimulation,while PIP,BNP and OHP was found to red-shift after pressure stimulation.The single crystal X-ray diffraction of compounds PYP and PIP revealed that intermolecular ?-stacking distance for the piezofluorochromic is main cause of the difference.