Synthesis and Fluorescent Properties of Dy(III) Complexes with 1,5-Bis(1′,3′-diphenyl-5′-pyrazolone-4′)-1,5-pentanedione (BDPPPD)

The binary and ternary complexes of Dy(Ⅲ) with 1,5 bis(1′,3′ diphenyl 5′ pyrazolone 4′) 1,5 pentanedione(BDPPPD),Dy 2(BDPPPD) 3·6H 2O and Dy 2(BDPPPD) 3(Phen) 2·2H 2O (Phen =1,10 phenanthroline),were prepared with molar ratio n (Dy 3+ )∶ n (BDPPPD)=2∶3 and n (Dy 3+ )∶ n (BDPPPD)∶ n (Phen )=2∶3∶2 at appropriate pH(～7) in dioxane,the yields being 91 2% and 89 6% respectively.The composition of the complexes was determined by chemical,elementary and thermal analysis,and the structure of the complexes was characterized by FT-IR spectra.The fluorescence spectra of the complexes were measured. The fluorescent emission peaks of the complexes are at nearly 481 and 576 nm corresponding to the 4F 9/2 → 6H 15/2 and 4F 9/2 → 6H 13/2 transition of Dy 3+ respectively,indicating that the complexes emit the characteristic fluorescence of Dy(Ⅲ).The second ligand Phen has the fluorescence intensity enhancement effect on the complex,the fluorescence intensity of the maximal emission (at 576 nm) of the ternary complex Dy 2(BDPPPD) 3(Phen) 2·2H 2O is 1 68 times as high as that of the binary complex Dy 2(BDPPPD) 3·6H 2O.The strong fluorescence of the complexes shows that the energy level of the triplet state of BDPPPD ligand matches well with the lowest excited state ( 4F 9/2 ) level of Dy 3+ ion,and that the absorption coefficient of BDPPPD is high.Therefore BDPPPD is an appropriate ligand for the fluorescent Dy(Ⅲ) complexes.