Synthesis, Assembly And Properties Of Schiff Base Macrocycles Containing Furan Subunit

The design and non-covalent assembly of organic functional macrocyclic molecules,and their self-assembled micro-nano materials have great potential application research value in the fields of materials,catalysis,photodynamic therapy,optoelectronic device development,and life sciences.The imide groups in the Schiff base macrocyclic molecules containing 2,6-diamide pyridine subunits are arranged in a cis-convergent arrangement.Based on the characteristics that N-H in the imide groups are easy to form hydrogen bonds,by adjusting the macrocyclic molecular structure.Modification,anticipation and regulation of non-covalently micro-nano assemblies of macrocyclic molecules and their functional properties.Based on the fact that the formation of imine bonds in the dehydration condensation reaction of Schiff bases has reversible properties and is sensitive to the stimuli of the reaction external conditions,on the one hand,the purpose of selectively obtaining the target macrocycle is achieved by adjusting the reaction conditions;on the other hand,using the process of self-assembly regulated by organic molecules Schiff bases has the nature of self-adjustment or self-repair.Through the regulation of reaction conditions,a series of novel self-assembled structures and micro-nano materials can be obtained,especially the assembled entities formed by non-covalent interactions.The structure of the building block（original organic molecule）still exists in the structure,which provides an important reference for the study of the mechanism of the self-assembly process of the microsphere material and the exploration of its practical application performance.So far,studies on the self-assembly of micro-nano structures and their application properties based on Schiff base dehydration condensation of organic functional macrocyclic molecules are still scarce.Therefore,this thesis designed and synthesized a series of organic macrocyclic molecules containing 2,6-diamide pyridine and methylene bridged bisfuran structural units based on the principle of Schiff base dehydration condensation reaction,and discussed the directional synthesis of Schiff base organic macrocyclic molecules.The conditions and methods of structural transformation were also investigated,and the assembly and properties of micro-nano particles by non-covalent interactions of organic macrocycles were investigated.1.Synthesize[1+1]or[2+2]Schiff base macrocycles by one-step reaction of Schiff base dehydration condensation,and investigate their non-covalent interaction of micro-nano particle assembly.Solid,core-shell or vesicle self-assembled microspheres with particle size distribution ranging from 250±25 nm,330±20 nm,350±20 nm,450±25 nm,600±30 nm,730±25 nm,780±20 nm,800 nm,850 nm,1000±50 nm,1800-2000 nm,etc.;Through the regulation of the assembly process,the fluorescent molecules were successfully embedded in the vesicles,which laid the preliminary foundation for the further research of functionalized micro-nanoparticles in fluorescent probes.The sponge-like microspheres with loose and porous structure obtained by assembly were used to investigate the adsorption of metal ions,which showed that the sponge-like microspheres had a good adsorption effect on noble metal ions Ag⁺.The adsorption properties were characterized by TEM and TEM-Mapping-EDS methods.At the same time,the interaction between macrocyclic molecules and Ag+in solution was investigated by UV-vis titration technique.2.Utilize precursor dialdehyde A（2,2-bis[5’-（2’-formylfuryl）]propane）and precursor diamine B₂(diamine N,N’-(3-aminobenzene[1+1]-type macrocycle M₃and[2+2]-type macrocycle M₅were synthesized by Schiff base dehydration condensation reaction,and the macrocycle M₅was synthesized by sodium borohydride.Reduction of ring M₃gave saturated macrocycle M₄.The structures of macrocyclic M₃,M₄and M₅were characterized by ¹H NMR,¹³C NMR,ultra-high-resolution mass spectrometry,UV-vis absorption spectroscopy and infrared absorption spectroscopy.,M₄crystal structure.The transformation process between[1+1]and[2+2]Schiff macrocycles induced by adding polar solvent water was systematically investigated by HPLC method.The structure showed that in pure methanol solvent,[1+1]was selectively obtained.]-type macrocycle M₃;and when methanol and water were used as mixed solvents（volume ratio of 4:1）,the reaction selectively generated[2+2]-type macrocycle M₅.The bonding effects of macrocyclic M₃and M₅on a series of transition metal ions were investigated by UV-vis absorption spectroscopy.The structures indicated that M₃and M₅could be used as Cr³⁺probes,and their interaction and bonding ratios with Cr³⁺ were 1:1 and 2:1.