Chirality Transfer Based On Perylene Bisimides

Supramolecular chirality,which can be simply regarded as chirality at a supramolecular level,is the result of molecular self-assembly.During the chiral self-assembly,an important issue is how the supramolecular chirality or the chiral nanostructures are produced.Propagation of chiral information through specific interactions and organization in materials or supramolecular assemblies is generally called chirality transfer.In such a process,the rational design and synthesis of precursors with tailored structure and function,it is always very important to identify and prepare suitable molecular building blocks for supramolecular self-assembly.Perylene biimides(PBIs),with their very well characterised self-assembly properties and strong absorption in the UV-vis region,are important building blocks in supramolecular self-assembly.In this dissertation,Perylene biimide derivatives(PBIs)with different structures and special functional groups were designed and synthesized,and the chiral transfer and supramolecular self-assembly based on these PBIs were studied systematically.Our aim is to build the multicomponent systems containing PBIs,and establish the dependence of the chiral transfer and supramolecular self-assembly on the structures of each compound.We expect that the present study will be an instructive step towards the rational design of specific and predictable chiral supramolecular systems.There are two main experimental studies in this dissertation as follow:1.We designed a multicomponent system containing L-aspartic acid-based perylene bisimides(APBI)and benzene carboxylic acids.The water-soluble anionic base forms of them(APBI-),which is well soluble in water,was employed as the precursors for the building blocks.Upon adding benzene carboxylic acids,protonation was expected to occur in a controllable way.We favored the hydrogen bonding between the carboxy groups in the APBI building blocks and those in the isomeric benzene dicarboxylic acids.Those benzene dicarboxylic acids,which also were auxiliaries for gelation,were used as the weak acids.In addition,introduction of two chiral handles at each end results in not only the effective bias of perylene stacks as manifested from strong exciton coupling of perylene chromophoes,but the chiral assembly of achiral benzene dicarboxylic acids.OPA and IPA could lead to the gel formation of APBI while TPA could not.The hydrogen bonding interaction between-COOHs has been found to be a very important factor for gel formation.Depending on the subtle structural changes of benzene dicarboxylic acids,we can adjust the properties of gels.2.A bola-form amphiphile with a perylene bisimide core and two benzaldehyde moieties attached to its periphery(BAPBI)was designed and synthesized.The self-assembly is expected to produce nonracemic helical BAPBI arrangements by binding enantiopure amino acid guests to the periphery of the BAPBI with dynamic covalent bonds.Induced CD signals in the absorption of perylene bisimide cores have shown the chiral arrangements of BAPBI.The reversibility of dynamic covalent bonds is used to implement reversible chiral transfer of PBIs arrangements.Generally,all of the active promoters with the same chirality induce the same helicity.However,in this work,two opposite helical aggregations are induced with L-phenylalanine and L-tyrosine,respectively.It is proposed that the ?-? stacking interaction between phenyl groups of amino acids plays a key role in the chiality transfer process,and the change of configurations of phenyl groups in amino acids lead to the chiral inversion of BAPBI arrangements.