A Research On Synthesis And Recognition Property Of A Self-assembled M₂L₄ Cage

Since the discovery of crown ether,cryptands,and calixarene,prodigious progress in the host-guest chemistry field have been accomplished.For example,during the past few decades,there has been an increasing effort concerning the rational design of new functional metal organic materials,such as discrete coordination cages.These architectures generate tunable shape and size cavities,which offer potential applications as containers for storage,recognition,delivery,or catalysis.Recently,it was shown that these hosts are capable of encapsulating inorganic catalysts,small peptide sequences,and even proteins.Classically,water-soluble polyhedra are effective hosts for aromatic organic guests by hydrophobic effect.In the same way,negatively charged cages can accommodate cationic organic or complex molecules.The positively charged metal cage can complex anion.The molecular recognition property towards the guest relies on the establishment of weak,simultaneous,and selective interactions.In this paper,Pd₂L₄ metal organic cage was synthesized,and the recognition properties of the cage on neutral and anions were studied.the main contents of this paper are as follows:1.The rational design of the structure of ligand L,the synthesis of the trimer with amide groups,the ligand has a hydrogen bond and the C-F bond directed to the inside of the cavity,all of which can be the binding sites of molecular recognition.2.The Pd₂L₄ metal organic cage A was successfully synthesized by the coordination of the synthesized ligand with Pd metal with planar square coordination.3.Study on the identification of neutral molecules such as carbohydrate,adamantane and its derivatives by metal organic A cage,and then study the anion recognition of K₂B₁₂F₁₂,F^-,Cl^-,Br^-and so on.4.To explore the causes of B₁₂F₁₂^2-recognition,we changed the structure of the ligand L and synthesized cage B,so we compared the recognition properties of cage A and cage B to determine the reason why cage A selectively recognizes B₁₂F₁₂^2-.In this paper,the structures of cage A and cage B were characterized by nuclear magnetic resonance,mass spectrometry and X-ray single crystal diffraction,and the structure of host-guest complexion of K₂B₁₂F₁₂2 was also characterized in detail.In the study of cage A and cage B on the identification of substances,¹H NMR were used frequently.