Artificial Light-harvesting System With Sequential Energy Transfer Based On Metallacycle For Information Encryption And Anticounterfeiting

With the energy crisis sweeping the world,various efforts have been made for the construction of light-harvesting system to simulate natural photosynthesis.Light-harvesting systems have shown potential applications in photochemical catalysis,biosensing and imaging,photodynamic therapy,luminescent materials and other fields.To date,among the reported artificial light-harvesting systems,the construction of multi-step energy transfer systems based on macrocyclic compounds still faces significant challenges.In this paper,we designed and synthesized the organic platinum(II)alkyne macrocyclic compounds MPy1-MPy4 based on pyrene unit,and used them to construct artificial light-harvesting systems.This paper is divided into three parts.Part I:The organic platinum(II)alkyne macrocyclic compound MPy1 containing hydrophilic chain was designed and synthesized.(1)Compound 5 was obtained according to our previous procedure.(2)Using methyl 3,5-dibromobenzoate as starting material,compound 6 was obtained by Sonogashira coupling reaction with 4-acetyneylpyridine hydrochloride.Compound 6 reacts with hydrazine hydrate to form compound 7.On this basis,compound 7 reacts with 1-pyrene formaldehyde to obtain compound 8.(3)The organic platinum(II)alkyne macrocyclic compound MPy1 is formed by the[3+3]coordination driven self-assembly of compound 5 and compound 8.Meanwhile,in order to explore the influence of hydrogen bond and hydrophilic chain,we designed and synthesized the control compounds MPy2-MPy4.Part ?:The AIE effect of MPy1-MPy4 in H₂O-DMSO mixed solution has been studied.It was found that MPy1 and MPy3 containing hydrophilic chain showed obvious AIE effect in a certain concentration range,while MPy2 and MPy4 without hydrophilic chain showed obvious ACQ effect.In addition,MPy1 and MPy2 showed significant fluorescence redshift,because the introduction of-C=N,which increases the effective conjugate length of the system.MPy1 and MPy3 monomer molecules have torsional conformation in dilute solution,when the water content is between 10%and 60%,the molecular aggregates restrict intramolecular rotation.In addition,the MPy1 and MPy3 with long hydrophilic chains further impedes stacking between molecules.When the water content is further increased,the fluorescence intensity was reduced,possibly because of the formation of less emissive nanoaggregates by random molecular packing.Part ?:The one-step artificial light-harvesting systems MPy1-ESY and MPy1-SR101 were constructed by MPy1 with ESY and SR101 respectively in the H₂O-DMSO.The antenna effect and energy transfer efficiency of MPy1-SR101 system are much lower than that of MPy1-ESY system.Therefore,MPy1-ESY system was selected as the energy donor for continuous light capture with SR101.Compared with MPy1-SR101 system,MPy1-ESY-SR101 system shows higher antenna effect and energy transfer efficiency.Based on the fact that MPy1 has almost no fluorescence in solid or pure solvent state,we printed the QR on fluorescent paper using MPy1-ESY-SR101 as ink,the two-dimensional code pattern on the fluorescent paper QR could not be readable when illuminated by 365 nm UV lamp.When fumigated by tetrahydrofuran steam,the QR was clearly visible and could be used for scanning.Therefore,we build a double encryption intelligent anti-counterfeiting system.