Assembly And Property Study Of Supramolecular Compounds Based On Keggin Type Polyoxometalates

In this paper,by using the classic Keggin type polyoxometalates?POMs?as the basic unit of building materials,4,4'-bipy?bipy?as rigid organic ligand and transition metal cations,we have successfully synthesized POM-based supramolecular crystal materials.First,we investigated the reaction system of Keggin type molybdates and nitrogen containing organic ligand,and got two unreported compounds[?Hbipy?₃PMo₁₂O₄₀]?1?and[?Hbipy??H₂bipy?PMo₁₂O₄₀]?2?.The structures of the materials were characterized by the combination of X-ray characterization and infrared characterization.The results show that all of the obtained compounds are supermolecular hybrids that composed of 12-molybdenum phosphoric acid and bipy.Furthermore,the polytungstates are used as the precursor.Through the reaction between transition metals and polytungstates,and bipy,three kinds of supramolecular hybrids based on Keggin type polytungstates are designed and prepared.The structures of the compounds were characterized by means of single crystal X-ray diffraction,infrared spectroscopy and electrochemistry.It is notable that compounds 3 and 4 are composed of polytungstates of the transition metal as a hetero atom,which is novel in the field of POMs.This paper provides a new strategy to obtain polytungstates,which is a heteropoly atom with transition metals.Addtionally,electrochemical properties of title compounds have been studied.The 3-CPE shows a good electrocatalytic activity toward reduction of NO₂^-?the CAT is ca.380%?,which is more excellent than the most of POM-based materials.