Luminescent Properties of Zeolite Modified by Eu(III) and Tb(III) Complexes

The luminescence of the sorbates of the Eu(III) and Tb(III) complexes on the CaA-type zeolite with derivatives of aliphatic and aromatic carbonic acids has been studied. It is shown that the luminescent materials obtained can be used as light regulators and transformers which absorb energy in the UV spectral region and transform it into visible radiation.     

Luminescent Hybrid Materials Based on Polymers of Poly(Alpha-Fluoroacrylates) Doped with Tb(III) Complex

This study is devoted to the development of efficient luminescent hybrid materials excited by UV radiation and featuring narrow luminescence lines as well as light, humidity, and temperature resistance. As a luminescent material, a terbium ion coordination compound introduced into the matrix of an organofluorine polymer is used. It has been shown that efficient excitation transfer to electronic levels of the terbium ion can be achieved by proper ligand selection. The polymer matrix material does not affect the luminescence properties of the Tb(III) coordination compound.     

Determination of Dy(III) in the presence of Tb(III) using time-resolved luminescence

We have measured the relative luminescence quantum yields and luminescence lifetimes of Tb(III) and Dy(III) ions in complexes with pyrazole-5-carboxylic acids. Based on study of the time-resolved luminescence spectra of Tb(III) and Dy(III) complexes with 3-(6-benzodioxanyl)pyrazole-5-carboxylic acid, we have demonstrated the possibility in principle of determining Dy(III) in the presence of Tb(III) by separating the short-lived component of the luminescence of dysprosium, despite the practically complete overlap of the analytical bands of dysprosium by the terbium bands. This method was used to determine Dy(III) in luminescent materials: scandium borates doped with terbium and dysprosium. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 3, pp. 327–331, May–June, 2007.     

Luminescent europium(III) and terbium(III) nicotinate complexes covalently linked to a 1,10-phenanthroline functionalised sol-gel glass

Sol-gel glasses with covalently linked lanthanide complexes are luminescent materials which can be processed at ambient temperatures, which have a good solubility and uniform distribution of the complexes in the host matrix. In this study, a luminescent terbium(III) complex was covalently coupled to an organic-inorganic hybrid material prepared by the sol-gel process. This was realised by use of nicotinate groups as the ligands for the terbium(III) ion. The [Tb(C₅H₄NCO₂)₃(phen)(H₂O)₂] complex was immobilised on the sol-gel glass matrix and showed a green photoluminescence upon irradiation with ultraviolet light. The nicotinate groups act as an antenna to absorb the incident light and channel the excitation energy to the terbium(III) ion. The sol-gel glass was also prepared for the corresponding europium(III) complex. In this case, excitation of the europium(III) ion was possible via both the nicotinate ligands and the 1,10-phenanthroline ligands. High-resolution luminescence and excitation spectra were recorded and the radiative lifetimes were measured.     

Luminescent Eu(III) and Tb(III) Complexes: Developing Lanthanide Luminescent-Based Devices

This mini review gives some highlights of the work recently carried out in our research group in Dublin on the developments of lanthanide luminescent devices, where the future goal is to produce devices that can operate as sensors. A few examples demonstrate our design principles for targeting both anion and cations that are of biological or pharmaceutical relevance, where the recognition occurs in aqueous competitive media. We also discuss the possibility of developing mixed f-d metal complexes and conjugates that can be employed as novel supramolecular architectures.     

Low-vibrational luminescent polymers including tris(bis-perfluoromethane and ethanesulfonylaminate)neodymium(III) with 8 coordinated DMSO-d6

Novel Nd(III) complexes, tris(bis-perfluoromethane and ethanesulfonylaminato)neodymium(III)octa(deuterated dimethylsulfoxide) were designed and synthesized to apply to luminescent materials in plastic optical fiber. The IR and the near-IR spectra analyses has been done to estimate the radiationless transition via vibrational excitation of the Nd(III) complexes. [Nd(pms)₃(DMSO-d₆)₈] and [Nd(pes)₃(DMSO-d₆)₈] in polyhexafluoroisopropylmethacrylate gave a emission quantum yield of 1.3% and 1.6%, which was the largest in luminescent Nd(III) polymers. A research field for telecommunication network using 1.3 μm light would be achieved by luminescent Nd(III) materials encapsulated low-vibrational coordination sites.     

Electrospinning preparation and photophysical properties of one-dimensional (1D) composite nanofibers doped with erbium(III) complexes

1D composite nanofibers of poly(vinylpyrrolidone) (PVP, M_W≈60,000) doped with three Er(III) complexes were prepared by electrospinning. They demonstrated strong near-infrared (NIR) photoluminescence (PL) at 1535 nm and ternary Er(TTA)₃Phen (denoted as Er2, where TTA=2-thenoyltrifluoroacetonate; Phen=1,10-phenanthroline) fibers (Er2/PVP) exhibited maximum PL intensity. The crystal structure of Er2 complex has been determined by X-ray diffraction measurements. Er2 doped in fibers exhibited better thermal stability of NIR PL than the pure Er2 complex. These luminescent composite fibers have potential application in optical amplifiers.     

Photo- and electroluminescence of mixed-ligand Eu(III) complexes

Spectral and luminescent properties of mixed-ligand Eu(III) complexes were studied in solutions and in polyvinylcarbazole (PVC) thin films. Trends in their variations were found depending on the complex structure and excitation mode. The electroluminescence was observed in ITO/PEDOT/Eu complex:PVC/CaMg/Al devices. Their current-voltage and voltage-brightness characteristics were investigated.     

Phosphorescent iridium(III) complexes with hetero (C ˆN) ligands

In order to improve luminescence efficiency, it is necessary to design a phosphorescent material which is capable of transferring the excited energy without triplet–triplet (T–T) annihilation. For this purpose, new types of metal complexes were designed with different species of (C ˆN) ligands. Herein, Ir(ppy)₂(piq), Ir(ppy)₂(piq-F) and Ir(ppy)₂(piq-CF₃) were designed and prepared, where ppy, piq, piq-F and piq-CF₃ represent 2-phenylpyridine, 1-(phenyl)isoquinoline, 1-(4′-fluorophenyl)isoquinoline and 1-(4′-trifluoromethylphenyl)isoquinoline, respectively. These Ir(III) complexes having two different ligands (hetero-Ir complexes) are expected to have a high luminescence efficiency by intramolecular energy transfer from the energy absorbing ligand to the luminescent ligand leading to a decrease in quenching or energy deactivation. To compare luminescent characteristics of these hetero-Ir complexes, homo-Ir complexes Ir(ppy)₃, Ir(piq)₃, Ir(piq-F)₃ and Ir(piq-CF₃)₃ were prepared and investigated photophysically.     

Design and Synthesis of a Terbium(III) Complex-Based Luminescence Probe for Time-Gated Luminescence Detection of Mercury(II) Ions

Time-gated luminescence detection technique using lanthanide complexes as luminescent probes is a useful and highly sensitive method. However, the effective application of this technique is limited by the lack of the target-responsive luminescent lanthanide complexes that can specifically recognize various analytes in aqueous solutions. In this work, a dual-functional ligand that can form a stable complex with Tb³⁺ and specifically recognize Hg²⁺ ions in aqueous solutions, N,N,N ¹ ,N ¹ -{[2,6-bis(3′-aminomethyl-1′-pyrazolyl)-4-[N,N-bis(3″,6″-dithiaoctyl)-aminomethyl]- pyridine]} tetrakis(acetic acid) (BBAPTA), has been designed and synthesized. The luminescence of its Tb³⁺ complex is weak, but can be effectively enhanced upon reaction with Hg²⁺ ions in aqueous solutions. The luminescence response investigations of BBAPTA-Tb³⁺ to various metal ions indicate that the complex has a good luminescence sensing selectivity for Hg²⁺ ions, but not for other metal ions. Thus a highly sensitive time-gated luminescence detection method for Hg²⁺ ions was developed by using BBAPTA-Tb³⁺ as a luminescent probe. The dose-dependent luminescence enhancement of the probe shows a good linearity with a detection limit of 17 nM for Hg²⁺ ions. These results demonstrated the efficacy and advantages of the new Tb³⁺ complex-based luminescence probe for the sensitive and selective detection of Hg²⁺ ions.     

Luminescent Properties of Europium(III) Compounds with Quinaldic Acid and Neutral Phosphorus-Containing Ligands with a Dimeric Structure

New luminescent mixed-ligand complexes of europium(III) with quinaldic acid and neutral phosphorus-containing ligands with a dimeric structure are synthesized. The structure and the thermal, spectral, and luminescent properties of mixed-ligand europium(III) complexes are studied. It is shown that the quinaldinate ion is coordinated to a europium(III) ion in a bidentate fashion. It is found that the excitation energy transfer to europium (III) ion occurs from levels of quinaldic acid and neutral phosphorus-containing ligands.     

Luminescence of water-soluble rh(III) porphyrins

The luminescent properties of complexes of rhodium(III) with three water-soluble porphyrins— meso-tetrakis(4-N-methyl pyridyl) porphyrin, meso-tetrakis(4-N,N,N-trimethyl aminophenyl) porphyrin, and meso-tetrakis(4-sulfonate phenyl) porphyrin—were studied. All three complexes were found to phosphoresce both at 77 K and in deaerated solutions at room temperature, with their fluorescence being very weak. The rate constants of radiative (k _p=40-60s^-1) and nonradiative deactivation of a triplet excited state were determined. It was ascertained that, in aqueous solutions, the phosphorescence is quenched by molecular oxygen via an energy-transfer mechanism that is accompanied by formation of singlet oxygen. The quantum yields of formation of singlet oxygen for all the metalloporphyrins studied were found to be close to unity, which is the quantum yield of formation of their triplet states.     

Evidence for Strong Mixing Between the LC and MLCT Excited States in Some Heteroleptic Iridium (III) Complexes

The synthesis, structure and photophysical properties of series of new luminescent cyclometalated Iridium (III) complexes are reported. The cyclometalated ligand used here is 2-aryl imidazole and the auxiliary ligand is acetyl acetone (acac). The crystal structure of the complex (dmdpi)₂Ir(acac) (5) show that the Iridium(III) ion resides in a distorted octahedral environment. All complexes exhibit bright photoluminescence (PL) at room temperature and (fpdmdmpi)₂Ir(acac) 4 has a high solution PL quantum efficiency of 0.56. The role played by electron releasing and electron withdrawing substituents of the 2-arylimidazole ligands towards the stability of HOMO and how the substituent influences the luminescent behaviour are discussed. Furthermore those substituents have effect on the contribution to mixing between ³(π-π*) and ³(MLCT) for the lowest excited states.     

铽配合物——蒙脱土新型复合发光材料的插层组装、表征和发光性能

合成了铽的配合物[TbL] (ClO₄)₃(L: 2, 2, 2', 2'-四[N-苯基-N-苄基(乙酰胺)-2-氧甲基]丁醚), 通过离子交换反应将配离子[TbL]³⁺插层组装到蒙脱土(MMT)层板间, 制备出了新型复合发光材料 [TbL]³⁺-MMT．用元素分析、X射线衍射、傅氏变换红外光谱和紫外-可见光谱对材料进行了表征, 对其荧光性质进行了研究．结果表明, 复合发光材料保持了蒙脱土良好的层柱结构特征和[TbL]³⁺离子的笼状结构特征, [TbL]³⁺离子以单层形式分布于蒙脱土层板间．在紫外光激发下, 复合发光材料发出较强的绿色荧光, 其发射光谱与相应配合物的发射光谱相似．与相应纯配合物比较, 复合发光材料单位质量Tb³⁺的相对荧光强度、荧光单色性和光稳定性有显著改善, 其激发波长向可见光区发生明显位移, 说明插层组装对相应配合物的激发波长有一定的调制作用.     

Effect of Bonding Scandium(III) ion to 1,3-Diketones on Their Luminescent Properties

We study the influence of bonding Sc(III) ion with 1,3-diketonate ligands on luminescent properties of 1,3-diketones in two complexes by means of optical spectroscopy. We show that the sensitization of the ligand luminescence of the complexes obtained increases from 0.8% for neat ligands and to 4% for the synthesized compounds; this fact is confirmed by the quantum yield measurements.     

高压下Na5Tb(WO4)4单晶的光谱

研究了Na5Tb(WO4)4单晶的高压发光规律,化学计量的Na5Tb(WO4)4基质发光单晶的发光来源于基质中高浓度Tb3+.用金刚石对顶砧显微光谱系统在0-4GPa范围内研究了Na5Tb(WO4)4的室温高压光谱,确定了各发射谱线的高压移动率.对Tb3+的5D4→7Fj(j=0,1,2,3,4,5),测到18条谱线高压移动率中除一条(5D4→7F2,常压峰值15509cm-1)蓝移外,都红移,红移率最大为-19.5cm-1/GPa(对应谱线5D4→7F4,常压峰值16876cm-1),与Tb3+在其它基质中相比,此移动率很大.     

Luminescence properties of europium (III) cryptates trapped in sol-gel glass

The Lanthanide complexes Eu-2.2.1 and Eu-2.2.2 were synthesized and then incorporated into silica based transparent organic-inorganic hybrid material by the sol-gel method as an example of how doped xerogel materials are emerging as an important means of producing new materials. The produced gels were diagnosed to monitor emission spectra of the luminescent trivalent europium (Eu³⁺) complexes; emissions were compared to those for gels containing uncomplexed Eu³⁺. Results of the experiments (emission and lifetimes) concerning the coordination sphere composition showed that a cryptand ligand with aromatic groups (short range effect) and the hydrophobic gel host (long range effect) settle efficient action in the antenna effect and isolate the central ion from efficient quenchers, as e.g. water molecules. Each ligand imposed a distinct splitting pattern on the europium emission bands that helps identify them.     

Theoretical oscillator strengths for some transitions in P(III), As(III), Sb(III) and Bi(III)

Relativistic as well as non-relativistic oscillator strengths have been calculated for transitions in the principal sharp and diffuse series of P(III), As(III), Sb(III) and Bi(III) spectra. The radial integrals were computed by employing the wave functions obtained from a semiempirical method which included exchange effects. A comparison is presented for our calculated f_ik values with experimental and other theoretical data. The influence of relativistic effects on oscillator strengths for transitions in the P(III) through Bi(III) homologous sequence is discussed.     

Luminescent Properties of a Composite of Acrylic Polymers Doped with Eu(III) Complex for Ink-Jet Printing Applications

We present a composite material based on polymer matrices doped with a new europium(III) complex exhibiting high quantum yield. The Eu(III) complex was introduced into two types of polymer matrices. We investigate the concentration influence of the complex embedded into polymers on luminescent properties of the composite material. This Eu(III) complex proved to be highly dispersible in polymers and compatible with ink-jet technology.     

Spectroscopic studies of lanthanide(III) ion complexes with diethyl(phthalimidomethyl) phosphonate

Complexation and photophysical properties of complexes of lanthanide ions, Ln(III), with diethyl(phthalimidomethyl)phosphonate ligand, DPIP, were studied. Interactions between Ln(III) and DPIP were investigated using Nd(III) absorption and Eu(III) and Tb(III) luminescence (emission and excitation) spectra, recorded in acetonitrile solution containing different counter ions (NO₃^-, Cl^- and ClO₄^-). Results of the absorption spectroscopy have shown that counter ions play a significant role in the complexation of Ln(III)/DPIP complexes. Studies of luminescence spectra of Eu(III) and Tb(III) ions proved that the formation of Ln(III)/DPIP complexes of stoichiometry Ln:L=1:3 is preferred in solution. Based on the results of elemental analysis, Nd(III) absorption spectra and IR and NMR data, it was shown that the DPIP ligand binds Ln(III) ions via oxygen from phosphoryl group, forming complexes of a general formula Ln(DPIP)₃(NO₃)₃·H₂O, in which the NO₃^- ions are coordinated with the metal ion as bidentate ligands. Luminescent properties and energy transfer, from the ligand to Ln(III) ions in the complexes formed, were studied based on the emission and excitation spectra of Eu(III) and Tb(III). Their luminescent lifetimes and emission quantum yields were also measured.