Synthesis,Characterization and Fluorescence Properties of Eu_x-Ho_((1-x))(BA)_3Phen Mixed Complexes
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The mixed RE complexes of Eu3+-Ho3+-phenanthroline-benzoic acid were synthesized in anhydrous ethanol.The composition of the RE complex was determined to be RE(BA)3 Phen(RE=Eu3+/Ho3+)by elemental analysis,IR and molar conductivity.The fluorescence characteristics of mixed complexes were investigated under 310 nm UV-light.The results showed that there was intensive interaction between europium ion and holmium ion,and the fluorescence emission intensity of europium ion was greatly sensitized by holmium ion.The red fluorescence of europium ion was emitted intensively in the mixed complexes.The fluorescence intensity of the complex in which n(Eu3+)∶n(Ho3+)=1∶1 was 2.2 times of the complex without Ho3+Keywords:
Europium
Holmium
Molar conductivity
Benzoic acid
Anhydrous
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In the anhydrous alcohol solution,the mixed solid complexes of Eu 3+ ,Tb 3+ Phenanthroline Salicylic Acid have been synthesized.The composition of the RE complexes are RE(Phen) 2(Sal) 2Cl·H 2O(RE=Eu 3+ ,Tb 3+ ) by the experiments of elemental alaysis,IR spectra,and mole conductivity.The fluorescence characteristics of mixed complexes were investigated.Excited by 351 nm UV light,the results of fluorescence spectra showed that there were intensive interactions between europium ions and terbium ions,the fluorescence emission intensity of europium ions were greatly sensitized by terbium ions and those of terbium ions were strongly quenched by europium ions.The red fluorescence of europium ions was emitted intensively in the mixed complexes.
Terbium
Europium
Phenanthroline
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Europium-gadolinium-poly(N-vinylacetamide) complexes were synthesized and characterized by UV-Vis absorption spectroscopy, FT-IR, and fluorescence spectroscopy. The results of UV-Vis and FT-IR suggested that europium and gadolinium ions be bonded to amide group of PNVA polymer. Fluorescence experiment indicated that the characteristic emission intensity of terbium ion was greatly increased and possibly sensitized by gadolinium ion. Moreover, the wavelengths of europium characteristic emissions were changed slightly.
Europium
Terbium
Amide
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It is well known that aromatic acids serve as excellent ligands to effect sensitization of lanthanide fluorescence. 1,3,5- H_3BTC has three carboxylate groups and displays widely varying coordination manner, functioning as a monodentate, bidentate, bridging or chelating ligand in complexes with metal ions. On the other hand, the rare earth carboxylate complexes are the active area of research due to their fluorescence and application in high-teach industry, the application foreground is very fast. In recent years, there are many studies carrying on the carboxylate complexes in order to look for the good fluorescent materials, one of the major activities in these studies is the enhancement of fluorescence by using of certain rare earth ions,such as La 3+,Y 3+and Gd 3+. The published dates on these were mainly focused on benzoic acid and benzene dicar- boxylate acid complexes, the complexes of trimesic acid with europium and lanthanum were comparatively scare. Only europium-trimesic acid fluorescence complexes were studied.A series of mixed rare earth complexes La_xEu_ 1-x (BTC) ·nH_2O ( H_3BTC = 1, 3, 5-H_3BTC, x= 0, 0.1, 0.3, 0.5, 0.7, 0.9) have been synthesized by the reaction of trivalent rare earth chlorides with trimesic acid. The contents of rare earth, C and H were measured by using EDTA titration method and a Vario EL elemental analyzer, the constitution of these complexes was confirmed respectively as follows: La_xEu_ 1-x(BTC)·nH_2O (x= 0, 0.1, 0.3, 0.5, 0.7, 0.9, n=0, 0.5,1.0).The IR spectra of free ligand and complexes were recorded by FTZR-8900 infrared spectroscopy with KBr pellet in the range of 350~3 500 cm -1. There is obviously difference between the ligand and complexes. The results show that the similar structures of the complexes and the different coordination functions of the carboxylate groups. Fluorescence spectra were carrying out by using a Hitachi F-4500 fluorescence spectrophotometer. The results indicate that the complex can emit intense characteristic fluorescence from europium ion, the emission peak centered at 578~582 nm (5D_0→7F_0),585~600 nm(5D_0→7F_1),605~630 nm(5D_0→7F_2),645~660 nm(5D_0→7F_3),685~700 nm (5D_0→7F_4), the intensity of the fluorescence of the series complexes were greater in 5D_0→7F_1 and 5D_0→7F_2, and both the positions show splitting emission peaks. These results show that the coordinating pattern of the carboxylate groups were different. In addition, the fluorescence intensities of europium ions were sensitized by the doping elements lanthanum ions, and the intensity of fluorescence is the best when La 3+∶Eu 3+=0.3∶0.7, but the position of the emission peak does not changed. In conclusion, a series of mixed rare earth complexes La_xEu_ 1-x (BTC)·nH_2O (x= 0, 0.1, 0.3, 0.5, 0.7, 0.9) have been synthesized by hydrothermal treatment. They can emit strong fluorescence.
Trimesic acid
Europium
Carboxylate
Benzoic acid
Lanthanum
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Three series of complexes (ten complexes) of europium with dibenzoylmethide have been synthesized. Their IR absorption spectra, fluorescence spectra and TG-DTA curves are studied. The results show that the complexes are oxidized and decomposed over 470 C. The emission spectra indicate that the fluorescence intensities of the ternary complexes are higher than the intensity of the binary complex Eu(DBM) 3 2H 2 O. In ternary complexes, EuDipy(DBM) 3 are stronger than EuPhen(DBM) 3 . In mixed rare earth complexes Re 0.5 Eu 0.5 Dipy(DBM) 3 (Re=Y 3+ , La 3+ , Gd 3+ and Sm 3+ ), there are weak sensitization actions from Y 3+ , La 3+ , Gd 3+ to Eu 3+ , and weak quench actions from Sm 3+ to Eu 3+ . The fluorescence emission intensity of Eu 0.5 La 0.5 Dipy(DBM) 3 is the highest among the complexes of different molar ratio of Eu 3+ to La 3+ .
Europium
Emission intensity
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In order to study regularity of fluorescence of complexes about rare earth with different benzoic acid,we have prepared much of BA-compiexes,RC_6H_4COOH(R=o-NH_2,H,p-NH_2,o-OH,m-Cl,o-COOH,m-COOH,p-COOH,p-OH,m-NO_2,3,5-Dinitro,p-Br,o-I,2-OH-5-SO_3H.They can be synthesized complexes with Sm~(3+),Eu~(3+),Tb~(3+),Gd~(3+).Under UV-excitation the complexes with Eu~(3+),Tb~(3+) have higher emitting(intensity) than complexes with Sm~(3+),Gd~(3+).There are some science bases about study a new luminophor.Spectra analyses of the complexes of europium with benzoic acid and its derivatives are discussed.The binary complexes of europium with benzoic acid and its derivatives(benzene carbonic acid,phthalic acid,isophthahc acid,salicylic acid,o-aminobenzoic acid sulfosalicylic acid) have been synthesized.They were characterized by(elemental) analysis,UV-Vis,IR,H NMR,fluorescence spectra and molar conductance.The UV spectra showed that the complexes' ultraviolet absorption were from the ligands(220~350 nm),so that it could transfer energy to rare earth.The measurement results of the emission spectra of the complexes indicated as follows the emission of Eu(BA)_3,Eu(m-Phth)_3·3H_2O and Eu(o-Phth)_3·3H_2O consisted of three peaks at 582,596,and 618 nm which were caused from ~5D_0→~7F_J(J=0,1,2) transition of Eu~(3+) respectively.Among these peaks the emission from ~5D_0→~7F_2 is the shrongest.But the emission of Eu o-aminobenzoic acid consisted(of three) peaks at 399,452,547 nm,and that of sulfosalicylic acid-Eu only one peak at 407 nm,which(were caused) from ligands.Fluorescence spectra show that there aren't red-characteristic emission of Eu in (Eu(o-Amino))_3 and Eu(Ssal)_3.
Benzoic acid
Europium
Phthalic acid
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The o amino benzoate complexes with the different molar ratio of Eu(Ⅲ) to Tb(Ⅲ) have been synthesized.The experimental results of the emission spectra excited by 369 nm UV light showed that the fluorescence intensities of one rare earth ion were influenced by the other.In the complexes,the fluorescence intensities of europium ions were sensitized by terbium ions and those of terbium ions were quenched by europium ions.
Terbium
Europium
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The series of complexes Tb_xY_(1-x)(BA)_3phen (BA=benzoate,phen=1,10-phenanthroline,x=0.1～1.0) was synthesized in the ethanol solution.Excitation and luminescence spectra of all the complexes were carried out and recorded at room temperature,then the relations between metals constitution of complexes and fluorescence strength are gained discussion.The results indicate that yttrium(Ⅲ) ion non-irradiating can obviously sensitize terbium(Ⅲ) ion irradiating.
Terbium
Phenanthroline
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Europium
Thenoyltrifluoroacetone
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Two series of solid complexes of europium and terbium with biphenyl 4-carboxylic acid and phen were synthesized and characterized in this report. Their elemental analysis, molar conductivities and TG-DTA studies indicate that the complexes have the composition of Eu(phen)L3·1/2H2O, Eu0.5RE0.5(phen)L3·1/2H2O; Tb(phen)L3·H2O and Tb0.5RE0.5(Phen)L3·1/2H2O. (RE=Y3+, La3+ and Gd3+; L=biphenyl 4-carboxylic acid; phen=o-Phenanthroline). The studies of their IR, UV 1H NMR and molar conductivities demonstrate that biphenyl 4-carboylic acid is bounded with RE(Ⅲ) ion. Rare earth ions coordinate with two nitrogen atoms of phen molecules directly in these rare earth complexes. The fluorescence spectra and fluorescence lifetimes of the rare earth complexes show that the fluorescent intensity and lifetime of a series of europium complexes are longer than those of the series of terbium complexes as having the some ligands. There are better fluorescent intensity and lifetime of hetero-nuclear rare earth complexes than homo-nuclear rare earth complexes for europium complexes. The fluorescence emission intensity of Eu3+ is raised by inert fluorescent rare earth ions (Y3+, Gd3+ and La3+), but in Tb3+ hetero-nuclear rare earth complexes the intensity of Tb3+ ions are quenched by the inert fluorescent rare earth ions.
Terbium
Europium
Biphenyl
Phenanthroline
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Complexes Eu2L3L' and Tb2L3L' (L = 0-phthalate, L' = 2,2'-dipyridyl) have been synthesized. Mixed the both complexes as different molar ratio, mechanically ground them, then obtained a series mixed solid complexes of europium and terbium. Their fluoresence and infrared spectra were investigated. The results showed that there were obviously change for their fluorescence intensities and peak positions as compared with Eu2L3L' or Tb2L3L'. The fluorescence intensities of europium ions were sensitized by terbium ions and those of terbium ions were quenched by europium ions. FTIR spectra indicated that there were a combined force between the two complexes in the mixed solid complexes.
Terbium
Europium
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