Synthesis of Complexes of Rare Earth Perchlorate with Diphenyl Sulfoxide and Benzoic Acid and Fluorescence of Tb~(3+) and Dy~(3+)

Six solid quaternary complexes of heavy rare earth perchlorate with diphenyl sulfoxide(L) and benzoic acid(L′)have been synthesized and characterized.By elemental analysis,TG-DTA and the molar conductivity measureraents,the composition of the complexes was suggested as [REL5L′(ClO4)](ClO4)(RE=Tb,Dy,Ho,Er,Tm,Yb;L=C6H5SOC6H5,L′= C6H5COO-).One of the two perchlorates(ClO4-) is coordinated with RE3+,while another is not.TG-DTA indicated that the decomposition temperature of the complexes is high,so they are thermostable.IR spectra and 1 HNMR studies indicated that the first ligand diphenyl sulfoxide(L) bonded with RE3+ by the oxygen atom in sulfinyl group while the second ligand benzoic acid(L′) bonded with RE3+ ions by one oxygen atom in carboxyl group which coordinate as an unidentate group.Fluorescent spectra of Tb3+ and Dy3+ complexes showed that quaternary complexes have the stronger fluorescence than the binary ones whose ligand is diphenyl sulfoxide(the fluorescence intensity of Tb3+ and Dy3+ complexes increased by 226% and 422% respectively).Phosphorescent spectra of two ligands showed that matching extent of triplet state of ligands with excited state of the rare earth have been increased by coordination of second ligand benzoic acid.In addition,there is a peak in the EPR spectrum of [Tb L5L′(ClO4)](ClO4) at the position of g=1.9920,it indicated that there is single electron in this complex,so the complex is paramagnetic.