A new β-diketone, 1-(p-phenylethynylphenyl)-1,3-butanedione (HPB), was synthesized and confirmed with elemental analysis, ¹H NMR and MS techniques. The result of ¹H NMR spectroscopy indicates that the HPB exists as an enol form isomer, which is in good agreement with the result of IR analysis. Four new binary rare earth complexes were synthesized by the reaction of HPB with Sm(III), Eu(III), Tb(III) and Dy(III), respectively. The compositions of the complexes were characterized by IR spectra, chemical analysis, elemental analysis and thermogravimetric analysis as Sm(PB)₃•2H₂O, Eu(PB)₃•3H₂O, Tb(PB)₃•2H₂O and Dy(PB)₃•3H₂O. At room temperature, under UV light excitation, the Sm(III), Eu(III), Tb(III) and Dy(III) complexes exhibit characteristic emission of the central ions. The fluorescence spectra show that the fluorescence emission intensity of Eu(III) complex is the strongest. The narrow strongest emission band of Eu(III) complex is considered to be a valuable material with bright red fluorescence. The experimental results are interpreted by quantum chemistry calculation.

Key words: β-diketone, lanthanide complex, luminescent property