Self-Assembly of Rod-Coil Amphipathic Molecules Driven by Donor-Acceptor Interactions

Author:Yu Sheng Sheng

Supervisor:jin long yi


Degree Year:2019





In this thesis,a series of rod-coil molecules with different rod segments.such as pyrene,anthracene and dianthranide units.were designed and synthesized.The self-assembly behavior of these molecules was studied in the bulk and in solutions.The self-assembly structures were precisely controlled by changing the molecular structure,such as the length of coil,the length of rod segment chiral group at the surface of rod segments and coil segments.The effect on self-assembled structures cauded by the slightly changes of these molecular structures is discussed,and the results exhibit the inherent relationship between the molecular structure and self-assembled structures.In addition,the rod segments of these rod-coil molecules composed of electron-rich conjugated units,which can interact with small electron-acceptor molecules through donor-acceptor interaction to form charge-transfer complexes.Therefore.the effects of donor-acceptor interaction on molecular self-assembly were further studied.The morphology of charge-transfer complexes was discussed detailly.and investigated its performance as supramolecular nanoreactors in aqueous solution.For the rod-coil molecules containing a pyrene unit.molecules A1-A3 with different length of rod segments or coil segments were designed and synthesized.The influence of the length of the coil segments and the size of the rod on the self-assembly structures of molecules A1-A3 and its charge-transfer complexes formed with tetranitrofluorenone were investigated.The results show that the length of the coil chain and the size of the rod segments have the similar effects on the self-assembly structures of the rod-coil molecules and their charge-transfer complexes in the bulk and aqueous solution.Increasing the length of the coil chains lead to decrease the intermolecular forces and more loose arrangement of molecules.Increasing the rod segments lead to increase intermolecular forces and enhance arrangement of molecular assembly.For the rod-coil molecules containing a dianthranide unit.molecule B1 with methyl groups at the surface of rod and coil segments.molecule B2 without methyl groups at the surface of rod and coil segments.were designed and synthesized.The effect of methyl groups at the surface of rod and coil segments on the self-assembly structures of rod-coil molecule in the solution was studied.The results imply,that the methyl groups at the surface of rod and coil segments could induce the formation of supramolecular chiral aggregates.In addition.the self-assembling behavior of charge-transfer complexes formed by with molecule B1 and B2 was studied.The results show that the donor-acceptor interactions would increase the intermolecular forces and lead to the increase of the aggregate size.It is worth noting that the aggregations have the response to the change of temperature caused by the dendritic coil chain.However,the donor-receptor interaction increased the intermolecular forces,resulting in disappearance of temperature stimuli.For the rod-coil molecules containing an anthranide unit molecules C1 and C2 molecules containing dendritic flexible chain were synthesized.Molecule C1 has the methyl groups at the surface of rod and coil segments.The self-assembling behavior of molecules C1 and C2 was studied in the water/tetrahydrofuran mixed solution.The results indicated that the methyl at the interface of rod and coil segments lead to decrease of the size of the aggregates in the mixed solution.In addition.molecules C1 and C2 can form charge-transfer complexes with or 2.4,6-trinitrophenol,The self-assembly of their charge-transfer complexes in mixed solutions was investigated.The results show that different electron-deficient molecules have the selectivity for the electron-rich groups of rod segments,and the aggregational structures of these charge-transfer complexes can be controlled by different electron-deficient molecules.Furthermore.these charge-transfer complexes can be used as efficient supramolecular nanoreactors.