Preparation And Fluorescent Properties Of Rare Earth (Europium, Terbium) Fluorescent Complexes And Fluorescent Falsification-resistant Inks

The study on the luminescence of rare earth complex, being the cross science of the luminescence of inorganic materials, organic materials and organism, is very important for the fundamental and applied research. The rare earth ion is a great treasure of luminescent materials since its abundant energy levels and 4f transition characteristics, and the rare earth elements provide a lot of luminescent materials and laser materials with good properties for high-new technique. The luminescence complexes of europium and terbium studied in this paper related to ones that can absorb radiant energy and can produce photoluminescence. The first ligands rated to these complexes principally are inexpensive benzoic acid and its derivatives, such as 8-diketones, which have good luminescent performance. Luminescent intensity of the complexes is improved and the cost is lowered by doping inexpensive no-fluorescent inert ions. Fluorescent agents with good disperse were prepared in the matrix of bisphenol A epoxy acrylate resin by in-situ and were successfully used in falsification-resistant inks, and fluorescent falsification-resistant inks with function of environment protection were prepared. At last, the fluorescent quenching mechanism was studied. Our main works are as followings:1. We synthesized the Europium complexes with red fluorescence and Terbium complexes with green fluorescence by using homogeneous precipitation and studied their fluorescent properties(1) Eu_1-xLn_x(BA)₃Phen, Eu_1-xLn_x(TTA)₃Phen (X=molar fraction of doping elements, Ln=Gd, La and Y, BA=benzoic acid, TTA=Thenoyltrifluoroacentone, Phen=1,10-phenanthroline) ternary complexes, Eu (AA)_x(TTA)_1-xPhen and Eu (TTA) SsalPhen (AA=crylic acid, Ssal=sulfosalicylic acid, X=1, 2) tetra-complexes were synthesized. Their properties were characterized by IR spectra, elemental analysis, fluorescent spectra and TG-DTA spectra. All of above complexes can emit characteristic fluorescence of europium ions. Fluorescence spectra showed that above Europium complexes have the order of fluorescent intensity from strongest to weakest: Eu(TTA)₃Phen, Eu(AA)(TTA)₂Phe, Eu(BA)₃Phen, Eu(AA)₂(TTA)Phen,Eu(TTA)SsalPhen. Synthesis and fluorescent properties of Eu(AA)x(TTA)3.xPhen and Eu(TTA)SsalPhen complexes were not reported in the literatures.(2) Complexes of Terbium with pyromellitic acid (PMA)(and trimellitic acid, TMA), complexes of Terbium with p-aminobenzoic acid (p-A) et al were synthesized. Their properties were characterized by IR spectra, elemental analysis, fluorescent spectra and TG-DTA spectra. All of above complexes can emit characteristic fluorescence of terbium ions. Fluorescence spectra showed that above Terbium complexes have the order of fluorescent intensity from strongest to weakest as follows: Tb (o-A)3, TbPMA3/4^Tb2 (Ssal)3, Tb (p-A)3, Tb (TMA), Tb-PMDMBA (PMDMBA= Bisphenol A epoxy acrylate resin modified with pyromellitic dianhydride). Among all of above complexes, study on synthesis and fluorescent properties of Tb-PMDMBA complex were not reported in the literatures, the complex can emit characteristic fluorescence.2. The parameter n was induced; fluorescent enhanced effects and mechanism of no-fluorescent doped ions were investigated.The results showed that no-fluorescent doped ions can enhance the fluorescent intensity of rare earth complexes, viz. p, values are more then 1, and when \i values gain with molar fraction of doping elements, fluorescent intensity gains. Then, fluorescent intensity weakens gradually after u values exceed optimum. Among these doped complexes of aromatic carboxylic acid, doping elements exist as dissimilar binary nucleus or multi-nucleus, their fluorescent enhancement mechanism belongs to intramolecular energy transfer, viz. "energy concentrating effect"; and then, in B-diketones complexes, doped ions and central ions form complexes with ligands respectively, their fluorescent enhancement mechanism belongs to intermolecular energy transfer, viz. "co-fluorescence effect".3. A series of europium fluorescent agents with red fluorescence and terbium fluorescent agents with green fluorescence were synthesized by in-situ for the first time in the matrix of bisphenol A epoxy acrylate resin (abbreviated EA), their properties were characterized by FTIR, UV-Vis spectra, fluorescent spectra et al.(1) The doped ternary complexes of europium with TTA and Phen, tetracomplexes of europium with TTA, cry lie acid (or sulfosalicylic acid ) and Phen, complex of europium with benzoic acid and phenanthroline were synthesized in EA. The above fluorescent agents have good tolerated and dispersal stability with the UV-curing resin. They can emit strong characteristic fluorescence of europium ion under ultraviolet radiation, Fluorescent intensity of above fluorescent agents have the order from strongest to weakest as follows: fluorescent agent FL-1 n fluorescent agent FL-IV, fluorescent agent FL- II ^ fluorescent agent FL-III, fluorescent agent FL-VI > fluorescent agent FL- V n fluorescent agent FL-VII -, fluorescent agent FL-V1II?(2) Binary complex of Terbium with sulfosalicylic acid, ternary complex of Terbium with sulfosalicylic acid and trioctylphosphine oxide, binary complex of Terbium with pyromellitic acid, ternary complex of Terbium with pyromellitic acid and trioctylphosphine oxide and binary complex of Terbium with p-aminobenzoic acid were synthesized in EA. The above fluorescent agents have tolerated and dispersal stability with the UV-curing resin. They can emit strong characteristic fluorescence of terbium ion under ultraviolet radiation. The fluorescent intensity of above fluorescent agents have the order from strongest to weakest as follows: fluorescent agents FL- X > fluorescent agents FL-IX> fluorescent agents FL-^ fluorescent agents FL-XIk fluorescent agents FL-XK4. Bisphenol A epoxy acrylate waterborne UV-curing resin modified by maleic anhydride (abbreviated: EB) and low adhesiveness waterborne UV-curing resin (abbreviated: EC) were synthesized. The resins are used as vehicles of inks, which has important environment protective function because the inks are improved from the solvent type of inks to the no-solvent type of inks.Effects of reaction conditions including temperature, time, type and content of catalyzes, type and content of polymerization-retarded on reaction velocity, degree of reaction and loss of double bond were investigated, the optimum conditions of reaction are ascertained.5. UV-curing (and waterborne UV-curing) falsification-resistant inks with red fluorescence and green fluorescence were prepared respectivelyRheology property, steady property, UV-curing property and fluorescent propertyof the inks are good. And effect factors of UV-curing mechanism and UV-curing velocity of inks were investigated.6. Fluorescent quenching effects and mechanism of rare earth fluorescent complexes in polymer-base were investigated for the first timeFluorescent quenching effects on rare earth fluorescent complexes caused by doped elements, type of ligands, type of resins and type of photoinitiators were investigated in the details, and correlative theory was discussed. "Fluorescent protective layer" model was put forward according to type of ligands which include strong electronegativity atoms or not. Fluorescence is safeguarded as "Fluorescent protective layer" which come from hydrogen bonding between strong electronegativity atoms of ligands and hydroyl groups of EA is formed, the fluorescence is quenched when "Fluorescent protective layer" is not formed. Fluorescent quenching effects and mechanism of resins on rare earth fluorescent complexes were investigated according to "static fluorescent quenching". Fluorescent quenching effects and mechanism of photoinitiators on rare earth fluorescent complexes were investigated according to "interfiltering effect".