Spectra Analyses of Europium Complexes with Benzoic Acid and Its Derivatives
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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.Keywords:
Benzoic acid
Europium
Phthalic acid
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Three new europium complexes, Eu(PFBA)3 (H2O)4, Eu(PFBA)3 Phen (H2O)3 and Eu(PFBA)3 TPPO (H2O)3, were synthesized using 4-(4-pyridyl formoxyl) benzoic acid (HPFBA), 1,10-phenanthroline (phen) and triphenyl phosphine oxide (TPPO) as the ligands. In the complexes, two characteristic absorption bands of HPFBA due to vO-H (3 000-2 200 cm(-1)) and v c=o (1 697 cm(-1)) disappear, the asymmetry stretching vibration v(as)(coo-) and symmetry stretching vibration v(s)(coo-) of carboxyl appear, and the deltav(v(as)(coo)) - v(s)(coo-)) values are all smaller than that of NaPFBA. The carboxyl group of the ligand HPFBA is dehydrogenated and coordinated to Eu3+ with a bidentate chelating mode. The fluorescence properties of the complexes were studied. Each complex shows five emission bands at about 583, 596, 618, 655 and 703 nm, which are assigned to the characteristic emission 5D0 --> -F(j) (J = 0, 1, 2, 3, 4) transitions of Eu3+, respectively. The fluorescence intensity becomes stronger after the addition of phen and TPPO, and TPPO is better, which is due to synergistic effect of the second ligands.
Europium
Phosphine oxide
Benzoic acid
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Two series of mixed rare earth complexes Eu1-xLnxBTC·0.5H2O(Ln=Gd,Y;x=0,0.1,0.3,0.5,0.7,0.9) were synthesized by hydrothermal method.The composing of the complexes was determined by element analyses and EDTA titration method.The complexes were characterized by IR spectra methods.The fluorescence spectra of all the complexes were recorded by using a fluorescence spectrophotometer at room temperature.The results indicated that the fluorescence intensity of the complexes were obviously enhanced when doping rare earth ion of Gd3+ or Y3+,and the different doped ions the sensitized degree was YGd.When n(Ln3+)∶n(Eu3+)=7∶3,the fluorescence intensity of Eu1-xLnxBTC·0.5H2O was the greatest.At 593 nm the fluorescence intensity of Eu0.3Gd0.7BTC·0.5H2O is 1.62 multiple of EuBTC·0.5H2O,and Eu0.3Y0.7BTC·0.5H2O is 1.96 multiple of EuBTC·0.5H2O.
Trimesic acid
Hydrothermal Synthesis
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A series of Eu 3+ (La 3+ ) complexes of phen and p phthalic acid were synthesized respectively. Their IR absorption spectra, UV absorption and fluorescence spectra were studied. The results show that the oxygen atoms from p phthalic acid and nitrogen atoms from phen coordinate to the rare earth ions in the complexes. The fluorescence emission of Eu 3+ ion can be greatly enhanced, if some of the europium ions in the complexes were substituted by lanthanum ions.
Europium
Phthalic acid
Lanthanum
Phthalic anhydride
Phenanthroline
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C 6H 5SCH 2COOH and the complexes of REL 3·nH 2O(RE=Nd 3+ ,Sm 3+ ,Eu 3+ ,Tb 3+ ,Dy 3+ ,L=C 6H 5SCH 2COO - ,n=1～4)have been synthesized It was confirmed that the composition of the complexes are REL 3·nH 2O(L=C 6H 5SCH 2COO -,n=1～4) by the elemental analysis It has been measured by IR spectra,UV spectra,fluorescent excitation and emission and molor conductivity It was confirmed that the coordination number of the complexes is 9 In the fluoresent spectra it was found that the complexes of Eu 3+ and Tb 3+ have stronger fluorescence In the solubility experiment it was found the complexes have high solubility in DMF and DMSO
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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+
Europium
Holmium
Molar conductivity
Benzoic acid
Anhydrous
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Seven solid complexes of proportional mixed complexes (Eu3+ mixed with La3+) of rare earth perchlorate with the 2-thiophene carboxylic acid and 1.10-phenanthroline were synthesized. By elemental analysis, coordination titration and molar conductance measurement, the composition of the complexes were suggested to be (Eu(1-x)La(x)) x L3 x phen x 1/2H2O (x = 0.000-0.200, L as 2-thiophene carboxylic acid and phen for 1.10-phenanthroline) respectively. The ligands and coordination compounds were studied by means of IR spectra and fluorescence excitation and emission spectra. The molar conductivities in DMF solvent suggested that the complexes are nonelectrolyte. IR spectra studies indicate that the 2-thiophene carboxylic acid ligands bonded with RE(II) through oxygen atoms in carboxyl group and 1.10-phenanthroline ligand is bonded to RE(III) through nitrogen atoms. In the fluorescence spectra it was found that the Eu3+ complex has no symmetrical center. La3+ has a great influence on the luminescence of Eu3+. The fluorescence emission intensity of Eu3+ was enhanced by La3+ and the fluorescence intensity with x = 0.050 is much higher. With La3+ concentration increasing the luminescence of Eu3+ is less intense.
Europium
Phenanthroline
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The present paper reports three new europium complexes, EuL3(H2O)6, EuL3Phen(H2O)4 and EuL3 (TPPO) (H2O)5, synthesized with Eu(NO3)3 x 6H2O, 2-(4-fluorobenzoyl) benzoic acid, Phen and TPPO(L = 2-(4-fluorobenzoyl) benzoic acid, Phen = 1, 10-phenanthroline, TPPO = triphenyl phosphine oxide). Their composition and chemical structures were characterized by elemental analysis, IR and 1H NMR spectroscopy. The IR spectra indicated that all complexes exhibited the characteristic peaks of carboxylate, asymmetric stretching vibration (vas (CO2(- and symmetric stretching vibration (vs (CO2(- peaks; the C = O stretching band at 1,692 cm(-1) of COOH and the O--H stretching band around 2,500-3,200 cm(-1) disappeared. All these complexes had a smaller Deltav(vas (CO2(-))-vs(CO2(- value than that of NaL, so the carboxylate groups coordinated with the europium ion in the form of bridging bidentate. In 1HNMR, the signals of hydrogen in 2-(4-fluorobenzoyl) benzoic acid became wide and shifted upfield, and those in Phen, TPPO shifted downfield. The excitation and emission spectra were recorded at room temperature. The excitation spectra showed that the optimum excitation peaks of these three complexes, EuL3 (H2O)6, EuL3Phen(H2O)5 and EuL3(TPPO)(H2O)5, were at 353.0, 355.0 and 357.0 nm, respectively. All these three complexes showed Eu3+ ion characteristic emission bands, the electron-dipole transition 5D0 --> 7F2 and magnetism dipole transition 5D0 --> 7F1; their emission peaks were at 596.0, 617.0; 596.0, 619.0; 595.0, 620.0 nm, and the relative intensities were 1.1, 8.6; 15.2, 100.0; 3.6, 23.2, respectively. The intensity of 5D0 --> 7F2 was stronger than that of 5D0 --> F1, which indicated that europium ions were at asymmetric center. The emission intensities of europium ions were greatly sensitized by Phen.
Europium
Benzoic acid
Carboxylate
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Binary complex was synthesized with ligands of europium and benzoic acid(BA),and ternary complex was synthesized with ligands of europium and benzoic acid(BA) and 1,10- phenanthroline(Phen).Their infrared absorption spectra,UV absorption and fluorescence spectra were studied.The results showed that UV spectra of the complexes mainly showed as a ligand absorption,energy was absorbed by ligand to transfer to center ion En~(3+).The infrared spectra of complexes were different from the ligand,the symmetry telescopic vibration of carboxyl v_s(coo-) to 1418cm~(-1),then the against symmetry stretching vibration of carboxyl v_(as)(coo-) shifted to 1562cm~(-1), that showed coordination bond was formed between europium and the ligand.Determination of fluorescence performance of the complexes and fluorescence security printing ink,ternary complex showed the fluorescence characteristics of centre ion Eu~(3+),the strongest peak of 616nm fluorescence emission spectral corresponded to ~5D_0→~7F_2 of Eu~(3+).The preparation of the fluorescence security printingink of rare earth is colorless in the visible,but it showed obvious red fluorescent in UV lamp.
Europium
Benzoic acid
Phenanthroline
Ternary complex
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A series of Eu(Ⅲ)/Gd(Ⅲ)complexes of benzoic acid(BA),2-thienyhrifluoroacetonate (HTTA)and Phenanthroline(Phen)are synthesized.Compositions of these complexes are revealed to be Eu_(1-x)Gd_x(BA)(TTA)_2Phen(x=0～1).Their IR spectra and fluorescent spectra are studied.The fluorescent excitation spectra of these complexs show broader excitation band and a peak position blue shift than that of Eu(TTA)_3Phen corresponding to their formation.The fluorescence enhancement of cofluorescence Gd~(3+)ions to the Eu(Ⅲ)complexes is clear.The optimum concentration of Gd~(3+)is 0. 4(molar fraction).The intermolecular transfer between Gd(BA)(TTA)_2 Phen and Eu(BA)(TTA)_2 Phen appears to be responsible for the fluorescence enhancement of Eu_(1-x)Gd_x(BA)(TTA)_2Phen.
Benzoic acid
Phenanthroline
Europium
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A series of dinuclear complexes of different molar ratio of Eu3+ to La3+ with benzoate and alpha,alpha'-dipyridyl have been synthesized in the anhydrous alcohol. Their composition was RE(Dipy)L3.H2O (RE = Eu3+ and La3+, L = C6H5COO-). Their UV spectra and IR spectra were studied. The UV absorption spectral peaks of benzoic acid and alpha,alpha'-dypyridyl shifted 2-9 nm in the complexes. The characteristic anti-symmetric and symmetric stretching vibrations of carboxylate group shifted to lower frequency, while the C=N stretching vibrations shifted to higher frequency in the complexes. These situations show that chemical bonds have formed between the ligands and the rare earth ions. The fluorescence spectra of the complexes were investigated, and the results indicate that the fluorescence emission intensity of europium ion was sensitized by lanthanum ion in the complexes. These facts show that not only the ligands but also the lanthanum complex can transfer the absorbed energy to Eu3+ ion in the complexes.
Lanthanum
Europium
Carboxylate
Benzoic acid
Anhydrous
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