Anion Coordination And Imine-Bond Co-Constructed Metal-Free Cages

Molecular cages have attracted increasing attentions due to diverse structures and functionalities.Among them,the constructions and properties of metal-coordinated supramolecular cages have been widely studied,and anion-coordinated supramolecular cages have been recognized gradually.Although anion cages are constructed by self-assembly strategy,the relatively complicated synthesis of anion coordination ligands is a critical problem inhibiting the development of anion cages.In this thesis,a high efficient synthetic strategy was developed by combing dynamic bonds?imine-bond?and supramolecular self-assembly strategies.The main content in this thesis including:the synthesis of C₂ or C₃ symmetric anion ligands obtained from one step reaction between bisurea-connected amines and C₂ or C₃ symmetric aldehydes,and the construction of triple helicates or tetrahedral cages by using these ligands to coordinate with anions.Furthermore,selective encapsulation of cation-guests was studied with these anion cages as the host receptors.This thesis is mainly divided into three chapters as follows.In the first chapter,we briefly described the background and development of organic-,metal-coordinated-,and anion-coordinated-molecular cages,as well as purpose and significance of this thesis.In the second chapter,we described the constructions and properties of anion triple helicate molecular cages synthesized from a C₂ symmetrical dialdehyde.Pyridinium-bisurea-amine was used as a fragment ligand to synthesize tetraurea ligand with glyoxal,m-phthalaldehyde,terephthalaldehyde or anthracene-?9,10?-dicarbaldehyde through the imine bond?dynamic covalent bond?.After the ligand coordinated with the phosphate anion,a series of metal-free anion triple helicate molecular cages were obtained as evidenced by results of NMR and HRMS.In the third chapter,we studied the constructions and properties of anion tetrahedral molecular cages.Isopropyl-bisurea-amine was used to synthesize hexaurea ligands,which were reacted with three different sized,C₃ symmetrical aldehydes by forming imine bonds?dynamic covalent bonds?.After the ligand coordinated with the phosphate anion,a series of metal-free anion triple helicate molecular cages were obtained as evidenced by results of NMR and HRMS.And the molecular cages with effective cavities can be achieved for the first time,whose selective encapsulation towards tetraphenylphosphine were tested by different characterization methods.