Study On Supramolecular Light-Harvesting System Based On AIE Type Donors And Their Application

Supramolecular self-assembly is greatly helpful for the development of AIE materials.Based on the research on supramolecular polymers and AIE-type materials reported previously,in this thesis,compounds with AIE properties,and their self-assembly behavior were studied.Moreover,artificial light-harvesting systems were constructed based on these AIE molecules,and the potential applications of these systems were explored.This thesis mainly consists of the following three parts:In the first part,an artificial light harvesting system based on quadruple hydrogen bonding supramolecular polymers was developed.An AIE type group（FTPE）bridged ditopic ureidopyrimidinone（UPy）derivative（M）was designed and synthesized.Through quadruple hydrogen bonding,M can form supramolecular polymers.With the help of the surfactant CTAB,the supramolecular polymers of M can be dispersed in water to form nanoparticles.Using M as the donor and the fluorescent dye NDI as the acceptor,the artificial LHS was successfully constructed in aqueous medium.By adjusting the ratio of M and NDI,multicolor tunable fluorescence emission from yellow to red can be achieved.The artificial light-harvesting system has potential applications in dynamic luminescent materials and bioimaging.In the second part,a sequential energy-transfer supramolecular artificial light-harvesting system based on a water-soluble pillar[5]arene and AIE guest was developed.A carboxylate-modified pillar[5]arene（WP5）host and a picoline-modified tetraphenylethylene derivative（Me Py TPE）guest were designed and synthesized.In water,WP5 can bind with Me Py TPE via host-guest interaction and further assemble into nanoparticles.We chose eosin Y（ESY）as the first energy acceptor and Nile red（Ni R）as the final energy acceptor,and successfully constructed a sequential energy-transfer light-harvesting system.By controlling the ratio of WP5-Me Py TPE,ESY,and Ni R,not only tunable emission from bright blue to yellow-green to pink,but also a white light emission can be obtained.In addition,the light-harvesting system can be used as a nanoreactor for photo-catalytic dehalogenation organic reactions in aqueous solution.This artificial light-harvesting system has potential applications in photocatalysis and organic light-emitting materials.In the third part,two molecules based on UPy and Schiff-base were synthesized.Firstly,compound N1 with AIE properties was designed and synthesized.Due to the poor solubility of compound N1,compound N2 was further synthesized by introducing an alkyl chain to increase the flexibility.We hope that compound N2 can dimerize through the UPy unit,and the Schiff-base moiety can undergo metal coordination with Cu²⁺to form orthogonal supramolecular polymers which can be used for constructing artificial light-harvesting system.