[Studies on the preparation, characterization and fluorescence property of rare Earth with alizarin yellow R].

Four rare earth complexes with alizarin yellow R have been prepared and characterized by elemental analysis, IR, UV and 1H NMR in this paper. Their general formula was determined as the following: Na[REL2] x 2H2O (RE = Sm, Eu, Tb, Y. NaHL = alizarin yellow R). The IR shows that the phenolic proton dissociates and the phenolic oxygen atom is coordinated to metals. The carboxylic oxygen atom is coordinated to metals by single dentate. The phenolic oxygen atom together with carboxylic oxygen atom chelates with ion forming a six-mumber ring. Two water molecules are coordinated to rare earth ion. The spectrum of the ligand shows that a band at 398 nm is shifted to 351-355 nm in the complexes showing that the carbonyl oxygen and phenolic oxygen atom are coordinated to the metal ion. The oxygen atom of group -NOq and nitrogen atom of -N = N- do not bind to metal ions. The strong red fluorescence of Eu (III) complexes is observed in the light of fluorescence lamp. Two strong fluorescence peaks of complex Na [EuL2] x 2H2O may be attributed to the fluorescence spectra of (5)D0 --> (7)F1 and (5)D0 --> 7F2 transitions of Eu3+.