The Synthesis Of Macrocycles Containing Pyridine Imide Groups And Their Recognition Of Anions (or Molecules)

Anions play an important role in the fields of chemistry,biology,medicine and ecology.The design and synthesis of artificial receptors with high selectivity for the recognition of anions and their identification of anions are continually being favored by researchers.Organic ligands based on pyridine-2,6-dicarboxamide based scaffolds can form complexes with cations,ruthenium nitrosyl,metal–oxygen species and can selectively recognize anionic and chiral molecules.The series of pyridylimido groups of organic ligands have been synthesized,and play an important role in the field of anion recognition and chiral molecular recognition.Therefore,in this paper,rigid pyridine-2,6-dicarboxamide Schiff base macrocycles and it’s reduction of macrocycle was designed and synthesized.The properties of the target macrocycles were also studied.This paper mainly focus on the following aspects:1.Synthesis of the target macrocycles（1）Synthesis of the rigid macrocycle L₁ containing pyridine-2,6-dicarboxamide unit.The[1+1]Schiff base macrocyclic compound L₁ has been synthesized via the condensation of dialdehyde and diamine in the presence of sulfuric acid.（2）SynthesisoftheflexiblemacrocycleL₂containing pyridine-2,6-dicarboxamide unit.The rigid was reduced to the corresponding saturated macrocycle L₂.2.Characterization of the target macrocycles（1）The composition of the target products（L₁ and L₂）were characterized by ¹H NMR,IR,MS spectra and elemental analysis respectively.（2）The crystal structures of L₂ was determined by the X-ray diffraction analysis.3.The study of the reaction between the macrocyclic compound L₁,L₂ with a series of anions（1）The recognition ability for a series of anions was surveyed by UV-vis absorption spectra technique,the results showed that L₁ and L₂ displayed a obvious recognition for AcO^-、HSO₄^-、H₂PO₄^-、HP₂O₇^3-.（2）The crystal structures of complex containing L₁ and HP₂O₇^3-.was determined by the X-ray diffraction analysis.4.The study of the reaction between the macrocyclic compound L₁,L₂ with H₄P₂O₇（1）When adding H₄P₂O₇ into the solution of L₁ and L₂ in CH₃CN,the solution of L₁changed from colorless to yellow,the solution of L₂ changed from colorless to pale yellow,orange,and finally pink.（2）The study of the reaction between the macrocyclic compound L₁,L₂ with H₄P₂O₇was surveyed by UV-vis absorption spectra technique and ¹H NMR.