Studies On The Synthesis Of Chiral Ligands And Influence On Fluorescent Properties Of Rare Earth Ions

Lanthanide coordination polymers have the advantages of high purity and weakinfluences of environment, which has a broad prospect of application in optical waveguide,OLEDs （organic light-emitting diodes） and fluorescent probe fields. Absorption ability of rareearth ions is weak, ligand that coordinated with lanthanide ion improves luminescent intensitythrough antenna effect, which makes lanthanide ion retaining the emission spectrumcharacteristics. But lanthanide coordination polymers have some factors to reduceluminescent and affect the application of materials. These factors contain low energy transferefficiency and competitive luminescence between ligand with center ions. The currentresearch about influence on material structure and luminescent properties of chiral ligands isless.According to the literature review, we found that the rare earth complexes formed bycoordination of chiral ligands and rare earth ions have been reported, yet researches on rareearth complexes of chiral thiophene derivatives were rarely explored. Considerring the S atomin thiophene ring can contribute to the energy transfer from single excited state S1to thelowest triplet excited state T1, we plan to synthetise complexes using L/D-amino acid andthiophene derivatives as ligand, and study the nature of chiral complexes. Four dopedeuropium complexes and seven rare earth complexes （Ln=Eu, Sm, Dy, Tb） have beensynthesized. In these complexes, thiophene-amide compound as the first ligand andNi（NO₃）_2·6H₂O, ZnO, Cu（NO₃）_2·3H₂O and CuO as the second metal ion and1,10-phen,4,4’-bipyridine as the second ligand. In addition, we obtained the crystal structures of six rareearth complexes and three chiral ligands. The properties of ligands and complexes arecharacterized by IR、X-ray diffraction.The thesis consists of the following several parts:1、The thiophene-2,5-dicarbonylic dichloride is regarded as a core of ligand, which hasobtained with thiophene-2,5-dicarboxylic acid and sulfoxide chloride. Five chiral ligandswere obtained via the reactions of L-leucine methyl ester hydrochloride、L-valine methyl esterhydrochloride、 L-isoleucine methyl ester hydrochloride、 L-alanine methyl esterhydrochloride、D-alanine methyl ester hydrochloride. Then on the base of amides, five kinds of carboxylic acid were obtained by the hydrolyzation of ester. Furthermore, the crystalstructures of2,5-thiophenedicarboxyl-L-isoleucine acid、2,5-thiophenedicarboxyl-L-valineacid and2,5-thiophenedicarboxyl-D-alanine acid.2、Five europium complexes were obtained in hydrothermal conditions. In thesecomplexes,2,5-thiophenedicarboxyl-L-leucine acid as the first ligand, which reactrespectively with Ni（NO₃）_2·6H₂O, ZnO, Cu（NO₃）_2·3H₂O, CuO and1,10-phen（the secondligand）. The properties of complexes are characterized by IR and fluorescence. Zn（Ⅱ） metalion increased luminescent intensity of Eu（Ⅲ） ion, while Ni（Ⅱ） and Cu（Ⅱ）ions have aquenching effect on luminescence of Eu（Ⅲ） ion.3、Four europium and samarium complexes were obtained in hydrothermal conditions. Inthese complexes,2,5-thiophenedicarboxyl-L-alanine acid and2,5-thiophenedicarboxyl-D-alanine acid as the first ligand,4,4’-bipyridine as the second ligand. The properties ofcomplexes are characterized by IR、TG-DTA and X-ray diffraction. we obtained the crystalstructures of four rare earth complexes. The crystal structures are similar with two chiralcomplexes. The coordination environment of rare earth ions and position of free water aredifferent. The properties of IR、TG-DTA and photo-induced luminescence are similar.4、Two dysprosium and terbium complexes were obtained in hydrothermal conditions. Inthese complexes,2,5-thiophenedicarboxyl-L-alanine acid as the first ligand,4,4’-bipyridine asthe second ligand. The properties of complexes are characterized by IR、TG-DTA、fluorescence and X-ray diffraction. The complexes emit characteristic light of Dy³⁺ion andTb³⁺ion. The luminescence of Tb³⁺ion is particular, the intensity of5^D₄�'7^F₃transition isbetter for the intensity of5^D₄�'7^F₅transition.