Synthesis of Complexes of Rare Earth Elements with N,N′,N″-Tri(2-Hydroxy-1-naphthaldehyde)-aminotriethylamine and Preliminary Study on Their Fluorescence Properties

The ligand N,N′,N″-tri(2-hydroxy-1-naphthaldehyde)-aminotriethylamine was synthesized previously and was reacted with an ethanol solution of rare earth,especially La3+,Sm3+,Y3+,Tb3+,Ce3+ or Eu3+,in a medium of ethanol and methylene chloride to give the corresponding rare earth complexes.Their molecular structures were characterized by the methods of NMR,elemental analysis,molar conductivity.IRS and differential thermal gravimetry.It was found that the structures of the complexes conformed to the formula of RE(NO3)3·L·4H2O,where RE represents the above mentioned rare earth ions and L represents the ligand molecule.It was shown by the results of fluorescence study that strong characteristic fluorescence was observed with 1×10-4mol·L-1 solution complex of Tb(Ⅲ) in DMSO solution at pH 7,and weak fluorescence was observed with the complex of Eu(Ⅲ) while no fluorescence were observed with the complexes of the other 4 rare earth ions.