Synthesis And Properties Of The Fluorescent Complexes Of Terbium Adulterated By Lanthanun And Gadolinium

Rare earth elements possess luminescent, electric and magnetic properties due to their particular electron structure, and can be used to manufacture many hi-tech materials, so they are called the resources of new materials. In this dissertation, a series of new green fluorescence complexes of teribium ion adulterated by cheap non- fluorescence lanthanum or gadolinium ions with the first ligands of the cheap and popular aromatic carboxylic acid (m-chlorobenzoic acid, p-methylbenzoic acid, methoxybenzoic acid, p-hydroxylbenzoic acid, benzoic acid, salicylic acid, p-aminobenzoic acid, sulfosalicylic acid) and 1,10-phenanthroline, and the second ligands of oleic acid and undecenoic acid have been synthesized under the best optimisation synthesis conditions. Their molecular compositions and structures were characterized by means of elemental analysis, EDTA titrimetric method, FT-IR and UV spectroscopies; their thermal properties were studied by thermal analysis instrument; their luminescent properties were investigated by means of fluorescence instrument. The main results are as follows:1. The thermal stability properties of the complexes of teribium adulterated by lanthanum or gadolinium have relationships with the structure of ligands and the adulteration content of lanthanum and gadolinium. The sequence of thermal stability of the fluorescence complexes of terbium adulterated by lanthanum or gadolinium with the aromatic carboxylic acid and undecenoic acid is Tb0.5Y0.5(PABA)2(UA)·3H2O>Tb0.5Y0.5(BA)2(UA)·3H2O > Tb0.5Y0.5(MCBA)2(UA)·3H2O > Tb0.5Y0.5(PHBA)2(U- A)·3H2O > Tb0.5Y0.5(MBA)2(UA)·3H2O > Tb0.5Y0.5(SA)2(UA)·3H2O > Tb0.5Y0.5(Ph- en)(UA)3·H2O>Tb0.5Y0.5(SSA)(UA)·2H2O. The sequence of thermal stability of the fluorescence complexes of terbium adulterated by lanthanum or gadolinium with the aromatic carboxylic acid and oleic acid is Tb0.5Y0.5(SA)2(OA)·3H2O >Tb0.5Y0.5(PMBA)2(OA)·3H2O > Tb0.5Y0.5(Phen)(UA)3·H2O > Tb0.5Y0.5(PABA)2(O- A)·3H2O > Tb0.5Y0.5(MCBA)2(OA)·3H2O > Tb0.5Y0.5(BA)2(OA)·3H2O > Tb0.5Y0.5(SS- A)(OA)·2H2O>Tb0.5Y0.5(MBA)2(UA)·3H2O.2. The adulteration of the non-fluorescence lanthanum or gadolinium ions can enhance the fluorescence intensity of the complexes of terbium. The sensitization of the non-fluorescence lanthanum or gadolinium ions to the terbium ion increased in the first and then decreased with the increment of adulteration content of lanthanum or gadolinium ions. The basic order of the fluorescence intensity of the complexes of terbium adulterated by lanthanum or gadolinium is that of 50% adulteration content >that of 75% adulteration content > that of 25% adulteration content > that of 100% adulteration content. The results indicate that the emission peaks of the fluorescence complexes of terbium adulterated by lanthanum or gadolinium ions changes little compared with that of corresponding fluorescence complexes, which means that the addition of lanthanum or gadolinium ions does not affect the characteristic emission peaks of the rare earth, but affect their fluorescence intensity very much.3. The fluorescence intensity of the complexes of terbium adulterated by lanthanum or gadolinium has relationships with the structure of ligands and complexes. The ability order of the first ligand transferring light energy to the central terbium ion for the TbkLa1-k(X)2(UA)·3H2O was that of salicylic acid > m-chlorobenzoic acid > p-aminobenzoic acid > p-methylbenzoic acid > methoxybenzoic acid > sulfosalicylic acid > 1,10-phenanthroline > p-hydroxylbenzoic acid > benzoic acid. The ability order of the first ligand transferring light energy to the central terbium ion for the TbkGd1-k(X)2(UA)·3H2O was that of m-chlorobenzoic acid > p-methylbenzoic acid > p-hydroxylbenzoic acid > salicylic acid > p-aminobenzoic acid > benzoic acid > methoxybenzoic acid > 1,10-phenanthroline > sulfosalicylic acid. The ability order of the first ligand transferring light energy to the central terbium ion for the TbkLa1-k(X)2(OA)·3H2O was that of salicylic acid > p-aminobenzoic acid > benzoic acid > methoxybenzoic acid > 1,10-phenanthroline > p-hydroxylbenzoic acid > sulfosalicylic acid > m-chlorobenzoic acid > p-methylbenzoic acid. The ability order of the first ligand transferring light energy to the central terbium ion for the TbkGd1-k(X)2(OA)·3H2O was that of p-aminobenzoic acid > salicylic acid > p-hydroxylbenzoic acid > 1,10-phenanthroline > benzoic acid > methoxybenzoic acid > m-chlorobenzoic acid > sulfosalicylic acid > p-methylbenzoic acid.4. The relationships between the luminescent intensity of the complexes of terbium adulterated by lanthanum or gadolinium and the adulteration content of lanthanum or gadolinium were studied by means of chart and table. The results indicate that the luminescent properties of title complexes are affected by the change of content of lanthanum or gadolinium ions, but there are not apparent change rule. The fluorescence enhancement factor R was introduced for the further investigation of the effect of lanthanum or gadolinium ions and content on the luminescent properties of title complexes. The adulteration of lanthanum or gadolinium ions cause the sensitization effect if R value is greater than 1, however, they cause quenching effect if R value is less than 1. The greater the value R deviate 1, the greater the effect of sensitization or quenching. The results indicate that the value R of the most of title complexes is greater than 1, and increases with the increment of the adulterationcontent of lanthanum or gadolinium ion, it demonstrates the sensitization of lanthanum or gadolinium ions to terbium ion increase with the increment of the adulteration content of lanthanum or gadolinium ions.