Synthesis and characterization of some Lanthanide (III) Complexes based on 2, 6-Diphenylisonicotinic acid

This paper presents the synthesis of four mononuclear lanthanide (III) complexes, possessing 2, 6-Diphenylisonicotinate as a ligand.The complexes were synthesized in aqueous solution at room temperature in a one to three molar ratios of the Ln (III) salt and the ligand, respectively.The white or grayish powdered complexes that formed were characterized by elemental analysis, ftir, uv, and Fluorescence spectroscopy. The ftir absorption spectra indicated that 2, 6-Diphenylisonicotinate acts as a bidentate ligand and coordinates to Ln (III) through the carboxylate oxygen and the adjacent carbonyl oxygen (–C=O).The UV absorption spectra of the complexes are similar in band profile and shape to the spectrum of the ligand except a slight blue shift of the absorption maxima. The excitation and emission spectra of the complexes are very much similar to that of the ligand with minor differences in excitation and emission wavelengths.The elemental analysis results show a good agreement between the calculated and found percentages of chn. Based on the elemental analysis andspectroscopic resultsof the four complexes, wesuggestthat the compounds formed are nine coordinate around the metal center and have the general formulaLn(C18H12NO2)3.3H2O.