Supramolecular Co-assembly Driven By Charge Transfer Forces

In this thesis,a series of rod-coil molecules were synthesized by using pyrene or naphthalene diimine(NDI)as the conjugated aromatic groups of the rod.The self-assembly behaviors of these molecules in bulk and aqueous solution were investigated in detail.We introduced Pyrene unit as electron-rich group and NDI unit as electron-poor group,designed and synthesized coil-rod-coil molecules P1,P2,N1 and N2.It was used to study the introduction of charge transfer forces to drive the co-assembly behavior of molecules in bulk and aqueous solution.In the bulk state,the self-assembly of coil-rod-coil molecules obtained a tetragonal perforated layered phase and an oblique columnar phase.In the aqueous solution,sheet-like,nanofibers ribbon and nanofibers structures were obtained.Subsequently,the molecules formed the copolymers PN1,PN2 by charge transfer,and the intermolecular co-assembly behavior was studied.In the bulk state,the body-centered tetragonal phase and hexagonal close-packed phase were obtained.In the aqueous solution,nanofibers and sheet-like,loose nanofiber ribbons were obtained respectively.We designed and synthesized the hydrophobic molecule N3 and amphiphilic molecule N4 based on the NDI unit.The charge transfer complexes PN13,PN23,PN14 and PN24 were formed with molecules P1 and P2 of the previous chapter,respectively.The main purpose was to change the hydrophilic or hydrophobic volume ratio of the system through intermolecular charge transfer.The influence of Optical Properties,Nuclear Nagnetic Resonance(NMR),Atomic Force Microscope(AFM),Transmission Electron Microscope(TEM)and other experiments on the assembly behavior was investigated.When the molecule N3 was added into the aqueous solution,the hydrophobic volume increased and rod-like,short-ribbon structure was obtained.However added the molecule N4,the hydrophilic volume increased and a sheet-like,loose nanofiber bundle structure was obtained.We also designed and synthesized the molecule P6 based on the pyrene unit.During the self-assembly process,The aromatic conjugated groups of pyrene units were closely packed in the internal structure,and the external hydrophilic PEO chain forms a structure similar to 18-crown-6 crown ether.So we call it crown-like ether molecule here.Subsequently,we added different metal ions into the aqueous solution of crown ether-like supramolecular to explore the effect of coordination on the self-assembly behavior..The results show that the metal ion can coordinat with the crown-like ether supramolecules,resulted in the volume of the hydrophilic part shrinks,and various self-assembly structures can be obtained by changing the intermolecular forces.