Design,Synthesis And Anion Recognition Of Pyrrole Compounds

Objective:Numerous inorganic and organic anions play essential roles in life,medicine,catalysis,and the environment.In biological systems,anions are ubiquitous.Amino acids,peptides,nucleotide salts,are representative organic anionic compounds,and many inorganic anions such as nitrate,carbonate,and halogen ions are also abundant in organisms.Some anion binding protein also completes the trans membrane transfer and cell signaling of anions in the body.Since the cyclic pyrrole compound has a hollow structure and a good hydrogen bonding ability,it can be used as a functional receptor for carbohydrates and anions.The recognition of specific molecules and ions has become a vital research topic in chemistry and biology.At present,scientists have successfully synthesized some ion probes through non-covalent interactions,but fewer probes have been manufactured with high selectivity and effective control of the recognition process.The purpose of this research is to use pyrrole as a five-membered heterocyclic ring,to take advantage of its unique conjugation,and its NH group on the bracelet can form hydrogen bonds,and to combine the photoisomerism of the azobenzene structure,so that implement subject and object identification.Thus,the enormous potential of polypyrrole compounds in the field of anion recognition research can be realized.Methods:The iodopyrrole intermediate was synthesized by de novo synthesis,and then the Suzuki coupling reaction,esterification,and acid ification were used to obtain the target compound.¹H-NMR,¹³C-NMR,HRMS were used to characterize the target compounds.And the target compounds can recognize Br^-,Cl^-,CN^-,F^-,H₂PO₄^-,HSO₄^-,NO₃^-,OAc^-ions.Based on the theoretical calculation results of Gaussian 16,the mechanism of ion recognition is reasoned.Conclusion:Six target compounds and sixteen intermediates were designed and synthesized,eight of them are brand new compounds,which have not been reported in the literature.An excellent ion probe candidate was selected through ion pre-titration experiments,individual ion titration,and DFT theoretical calculations were carried out.The mechanism of interaction between probe and atom was conclusively deduced and explained.