Terminal group effects on the fluorescence spectra of europium(III) nitrate complexes with a family of amide-based 2,3-dihydroxynaphthalene derivatives

Three ligands 2,2′-[2,3-naphthylenebis(oxy)]-bis(N,N-diethyl(acetamide)) (La), 2,2′-[2,3-naphthylenebis(oxy)]-bis(N,N-diisopropyl(acetamide)) (Lb) and 2,2′-[2,3-naphthylenebis(oxy)]-bis(N,N-dibutyl(acetamide)) (Lc) and their europium(III) nitrate complexes were synthesized. The complexes were characterized by elemental analysis, IR, fluorescence spectroscopy and conductivity. The europium atoms are coordinated by O-atoms from CO, Ar–O–C. With the difference of the ligands, the solid fluorescent intensities of the Eu complexes vary regularly. Some factors that influencing the fluorescent intensity were discussed.