Synthesis and fluorescence properties of lanthanide(III) complexes of a novel bis(pyrazolyl-carboxyl)pyridine-based ligand.
A novel bis-pyrazolyl-carboxyl ligand, 2,6-bis(5-methyl-3-carboxypyrazol-1-ylmethyl)pyridine (L), was designed and synthesized and its several lanthanide(III) complexes Eu(III), Tb(III), Sm(III) and Gd(III) were successfully prepared and characterized in detail based on elemental analysis, infrared, mass, proton nuclear magnetic resonance spectroscopy and TG-DTA studies. Analysis of the IR spectra suggested that each of the lanthanide metal ions coordinated to the ligand via the carbonyl oxygen atoms and the nitrogen atom of the pyridine ring and pyrazole rings. The fluorescence spectra exhibits that the Tb(III) complex and the Eu(III) complex display characteristic metal-centered fluorescence in solid state while ligand fluorescence is completely quenched. However, the Tb(III) complex displays more effective fluorescence than the other complexes, which is attributed to especial effectivity in transferring energy from the lowest triplet energy level of the ligand (L) onto the excited state ((5)D(4)) of Tb(III).
Shi
Xiao-Ming
XM
School of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, PR China.
Tang
Rui-Ren
RR
Gu
Guo-Liang
GL
Huang
Ke-Long
KL
D004055:Differential Thermal Analysis; D028581:Lanthanoid Series Elements / Q000138:chemical synthesis* / Q000737:chemistry*; D008024:Ligands; D011720:Pyrazoles / Q000138:chemical synthesis* / Q000737:chemistry*; D011725:Pyridines / Q000138:chemical synthesis* / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013055:Spectrophotometry, Infrared; D013696:Temperature; D013818:Thermogravimetry
C539729:2,6-bis(5-methyl-3-carboxypyrazol-1-ylmethyl)pyridine; D028581:Lanthanoid Series Elements; D008024:Ligands; D011720:Pyrazoles; D011725:Pyridines