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1.
The apoferritin protein and apoferritin–Tb3+ complex were demonstrated to form oligomeric and polymeric self‐assemblies in neutral aqueous solutions, based on characterization by using luminescence and UV/Vis spectroscopy, dynamic light scattering, and transmission electron microscopy. Addition of a 20‐mer or higher poly(arginine) to the solution resulted in coprecipitation through nanoscale interactions, while biological proteins and other poly(amino acids) rarely yielded precipitates under the conditions employed. The apoferritin–Tb3+ complex assembly exhibited a particularly long‐lived green luminescence in aqueous solution, and its poly(arginine)‐selective precipitation behavior was followed by monitoring the changes in luminescence. The poly(arginine)‐tagged albumin precipitated selectively and quantitatively, so that the apoferritin–Tb3+ complex can function as a new luminescent biotool for the sensing of poly(arginine) and its protein conjugates.  相似文献   

2.
《中国化学》2017,35(11):1678-1686
Polydiacetylenes (PDAs), an organic layered compound, show a series of intriguing properties, such as thermochromism and fluorescence emission in the red‐phase. However, their irreversible color change, and weak and single‐color fluorescence emitted only from the red‐phase PDAs, have limited their applications. Herein, we report double‐reversible PDA‐Tb3+ nanosheets of which both the color and the fluorescence can be reversibly switched between two colors. PDA‐Tb3+ nanosheets have the nearly defect‐free intercalated structure in which a layer of Tb3+ ions was intercalated in between each two PDA bilayers to tether almost all of the carboxyl groups at the end of the side chains of the PDA. When the PDA is in the blue phase, the PDA‐Tb3+ nanosheets emit the green fluorescence of Tb3+ ions. When the PDA is in the red phase, the Tb3+ fluorescence disappears while the intrinsic red fluorescence of PDA is effectively enhanced through the fluorescence resonance energy transfer (FRET) process; the PDA‐Tb3+ nanosheets emit stronger red fluorescence compared with the PDA in red phase. Moreover, the tethering of almost all of the carboxyl groups at the end of the side chains of the PDA endows the nanosheets with the double reversibility in both the color and fluorescence transitions.  相似文献   

3.
Two macrobicyclic ligands derived from an 18‐membered tetralactam ring and 2,2′‐bipyridine or 2,6‐bis(pyrazol‐1‐yl)pyridine moieties, 1 and 2 , respectively, form stable complexes with GdIII, EuIII, and TbIII ions in aqueous solution. The ligand‐based luminescence is retained in the GdIII cryptates, whereas this radiative deactivation is quenched in the EuIII and TbIII cryptates by ligand‐to‐metal energy transfer, resulting in the usual metal‐centered emission spectra. Singlet‐ and triplet‐state energies, emission‐decay lifetimes, and luminescence yields were measured. [Tb⊂ 1 ]3+ cryptate shows a long luminescence lifetime (τ=1.12 ms) and a very high metal luminescence quantum yield (Φ=0.25) in comparison with those reported in the literature for Tb3+ complexes sensitized by a bipyridine chromophore. By comparison to [Ln⊂ 1 ]3+, [Ln⊂ 2 ]3+ presents markedly lower luminescence properties, due to worse interaction between the 2,6‐bis(pyrazol‐1‐yl)pyridine unit and the metal ion. Moreover, the luminescent metal and the triplet ligand energy levels of [Eu⊂ 2 ]3+ do not match. The effects of H2O molecules coordinated to the metal centre and of thermally activated decay processes on nonradiative deactivation to the ground‐state are also reported.  相似文献   

4.
Fluorescence intensities of poly(2‐vinylpyridine) (P2VP) and poly(4‐vinylpyridine) (P4VP) in H2SO4/H2O solutions were increased with increasing acid concentration. The intensities for P2VP were found to be six times stronger than that of P4VP. These differences were accounted for by the microenvironment of protonated pyridinium group. The ion binding properties of 4‐methylpyridine (4MP), P2VP, and P4VP were investigated in methanol using Tb3+ as a fluorescence probe. The increase of fluorescence intensity of Tb3+ in [P2VP–Tb3+] and [P4VP–Tb3+] complexes is due to both the replacement of the inner coordinated methanol molecules and ligand‐to‐metal energy transfer. The model compound 4MP was inefficient from this point of view, and the results were attributed to the polymer cooperative effect. Reduced viscosities of poly(vinylpyridine)s (PVP) in methanol were similar to nonionic polymers; however, when TbCl3 was added into the solution, the viscosities increased upon dilution. These results also indicated that PVP form complexes with Tb3+ in methanol. When diluted, the counterions Cl are allowed to dissociate and the charged polymer expands. Consequently, the solution's viscosity increases. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1341–1345, 1999  相似文献   

5.
A lanthanide‐complex‐based ratiometric luminescence probe specific for peroxynitrite (ONOO?), 4′‐(2,4‐dimethoxyphenyl)‐2,2′:6′,2′′‐terpyridine‐6,6′′‐diyl]bis(methylenenitrilo)tetrakis(acetate)‐Eu3+/Tb3+ ([Eu3+/Tb3+(DTTA)]), has been designed and synthesized. Both [Eu3+(DTTA)] and [Tb3+(DTTA)] are highly water soluble with large stability constants at ≈1020, and strongly luminescent with luminescence quantum yields of 10.0 and 9.9 %, respectively, and long luminescence lifetimes of 1.38 and 0.26 ms, respectively. It was found that the luminescence of [Tb3+(DTTA)] could be quenched by ONOO? rapidly and specifically in aqueous buffers, while that of [Eu3+(DTTA)] did not respond to the addition of ONOO?. Thus, by simply mixing [Eu3+(DTTA)] and [Tb3+(DTTA)] in an aqueous buffer, a ratiometric luminescence probe specific for time‐gated luminescence detection of ONOO? was obtained. The performance of [Tb3+(DTTA)] and [Eu3+/Tb3+(DTTA)] as the probes for luminescence imaging detection of ONOO? in living cells was investigated. The results demonstrated the efficacy and advantages of the new ratiometric luminescence probe for highly sensitive luminescence bioimaging application.  相似文献   

6.
The incorporation of impurity ions or doping is a promising method for controlling the electronic and optical properties and the structural stability of halide perovskite nanocrystals (NCs). Herein, we establish relationships between rare‐earth ions doping and intrinsic emission of lead‐free double perovskite Cs2AgInCl6 NCs to impart and tune the optical performances in the visible light region. Tb3+ ions were incorporated into Cs2AgInCl6 NCs and occupied In3+ sites as verified by both crystallographic analyses and first‐principles calculations. Trace amounts of Bi doping endowed the characteristic emission (5D47F6‐3) of Tb3+ ions with a new excitation peak at 368 nm rather than the single characteristic excitation at 290 nm of Tb3+. By controlling Tb3+ ions concentration, the emission colors of Bi‐doped Cs2Ag(In1?xTbx)Cl6 NCs could be continuously tuned from green to orange, through the efficient energy‐transfer channel from self‐trapped excitons to Tb3+ ions. Our study provides the salient features of the material design of lead‐free perovskite NCs and to expand their luminescence applications.  相似文献   

7.
《化学:亚洲杂志》2017,12(7):768-774
Bridged polysilsesquioxanes (BPs) show great potential in the development of lanthanide‐based luminescent materials, owing to their capacity to loading lanthanide complexes with high concentration and their flexible processability. A novel BP precursor, consisting of a C 3‐symmetrical benzene central core moiety, capable of sensitizing the luminescence of Eu3+ and Tb3+ is reported. Tunable, full‐color luminescent gels were facilely prepared by mixing the as‐synthesized precursor and Ln3+ ions in appropriate solvents. By either changing the Eu3+/Tb3+ molar ratio or altering the excitation wavelength, the emission colors of the final gels can be finely tuned. Additionally, the yellow‐colored emissive gel with a molar ratio of Eu3+ to Tb3+ of 0.5 can be used as an effective ratiometric luminescent sensor for distinguishing amines with lower pK a (<5) from those with higher pK a (>9).  相似文献   

8.
Highly uniform and well‐dispersed CaF2 hollow spheres with tunable particle size (300–930 nm) have been synthesized by a facile hydrothermal process. Their shells are composed of numerous nanocrystals (about 40 nm in diameter). The morphology and size of the CaF2 products are strongly dependent on experimental parameters such as reaction time, pH value, and organic additives. The size of the CaF2 hollow spheres can be controlled from 300 to 930 nm by adjusting the pH value. Nitrogen adsorption–desorption measurements suggest that mesopores (av 24.6 nm) exist in these hollow spheres. In addition, Ce3+/Tb3+‐codoped CaF2 hollow spheres can be prepared similarly, and show efficient energy transfer from Ce3+ to Tb3+ and strong green photoluminescence of Tb3+ (541 nm, 5D47F5 transition of Tb3+, the highest quantum efficiency reaches 77 %). The monodisperse CaF2:Ce3+/Tb3+ hollow spheres also have desirable properties as drug carriers. Ibuprofen‐loaded CaF2:Ce3+/Tb3+ samples still show green luminescence of Tb3+ under UV irradiation, and the emission intensity of Tb3+ in the drug‐carrier system varies with the released amount of ibuprofen, so that drug release can be easily tracked and monitored by means of the change in luminescence intensity. The formation mechanism and luminescent and drug‐release properties were studied in detail.  相似文献   

9.
A rare example of an organometallic terbium single‐ion magnet is reported. A Tb3+–[1]ferrocenophane complex displays a larger barrier to magnetization reversal than its isostructural Dy3+ analogue, which is reminiscent of trends observed for lanthanide–bis‐phthalocyanine complexes. Detailed ab initio calculations support the experimental observations and suggest a significantly larger ground‐state stabilization for the non‐Kramers ion Tb3+ in the Tb complex than for the Kramers‐ion Dy3+ in the Dy complex.  相似文献   

10.
Production of hybrid organic/inorganic complexes such as lanthanide phosphors in the nanodomain for human fingerprint visualization and anti‐counterfeiting ink under biocompatible UVA and blue light has not yet been studied that thoroughly. This paper presents the preparation of novel, bifunctional, green and red nanophosphors based on Eu3+ and Tb3+ complexes with quinolinone ligand (H2L). They have been prepared and characterized for latent fingerprint detection and anti‐counterfeiting ink applications. The analytical data confirm that the ligand acts in a monoanionic bidentate manner through OO donor sites, forming mononuclear complexes, formulated as [Ln(HL)3(C2H5OH)3] (Ln = Eu3+ or Tb3+; L = 1‐ethyl‐4‐hydroxy‐3‐(nitroacetyl)quinolin‐2‐(1H)‐one). The Eu3+ and Tb3+ complexes have nanospherical morphologies with average particle sizes of 17 and 5 nm, respectively. Pure red and green photoluminescence with long lifetime values has been obtained from the Eu3+ and Tb3+ complexes, respectively, under non‐harmful UVA and blue illumination. Latent fingerprint details, including their characteristic three levels, have been clearly identified from various forensic (non‐porous, semi‐porous, highly fluorescent porous) substrates using red (Eu3+) and green (Tb3+) nanophosphors. The green nanophosphor powder has a greater capability for visualizing latent fingerprints from highly fluorescent porous surfaces as compared to the red one. Both nanophosphor complexes have been used to develop luminescent ink for anti‐counterfeiting applications.  相似文献   

11.
The synthesis of lanthanides other than cerium in the oxidation state +IV has remained a desirable but unmet target until recently, when two examples of TbIV with saturated coordination spheres were isolated. Here we report the third example of an isolated molecular complex of terbium(IV), where the supporting siloxide ligands do not saturate the coordination sphere. The fully characterized six‐coordinate complex [TbIV(OSiPh3)4(MeCN)2], 2 ‐TbPh, shows high stability and the labile MeCN ligands can be replaced by phosphinoxide ligands. Computational studies suggest that the stability is due to a strong π(O?Tb) interaction which is stronger than in the previously reported TbIV complexes. Cyclic‐voltammetry experiments demonstrate that non‐binding counterions contribute to the stability of TbIV in solution by destabilizing the +III oxidation state, while alkali ions promote TbIV/TbIII electron transfer.  相似文献   

12.
Three new isostructural 3D lanthanide metal–organic frameworks (Ln‐MOFs), {H[LnL(H2O)]?2 H2O}n ( 1‐Ln ) (Ln=Eu3+, Gd3+ and Tb3+), based on infinite lanthanide‐carboxylate chains were constructed by employing an ether‐separated 5,5′‐oxydiisophthalic acid (H4L) ligand under solvothermal reaction. 1‐Eu and 1‐Tb exhibit strong red and green emission, respectively, through the antenna effect, as demonstrated through a combination of calculation and experimental results. Moreover, a series of dichromatic doped 1‐EuxTby MOFs were fabricated by introducing different concentrations of Eu3+ and Tb3+ ions, and they display an unusual variation of luminescent colors from green, yellow, orange to red. 1‐Eu with channels decorated by ether O atoms and the open metal sites displays good performance for CO2 capture and conversion between CO2 and epoxides into cyclic carbonates.  相似文献   

13.
The Tb3+ transport in dispersion supported liquid membrane (DSLM) consisting of polyvinylidene fluoride membrane (PVDF) as the liquid membrane support and dispersion solution including HCl solution as the stripping solution and 2‐ethyl hexyl phosphonic acid‐mono‐2‐ethyl hexyl ester (P507) dissolved in kerosene as the membrane solution, has been studied. The effects of pH value, initial concentration of Tb3+ and different ionic strength in the feed phase, volume ratio of membrane solution and stripping solution, concentration of HCl solution, concentration of carrier, different stripping agents in the dispersion phase on transport of Tb3+ has also been investigated, respectively. As a result, the optimum transport conditon of Tb3+ was that concentration of HCl solution was 4.0 mol/L, concentration of P507 was 0.10 mol/L, and volume ratio of membrane solution and stripping solution was 1.0 in the dispersion phase, and pH value was 5.2 in the feed phase. Ionic strength had no obvious effect on transport of Tb3+. Under the optimum condition studied, when initial concentration of Tb3+ was 1.0×10?4 mol/L, the transport rate of Tb3+ was up to 95.2% during the transport time of 95 min. The kinetic equation was developed in terms of the law of mass diffusion and the theory of interface chemistry. The results were in good agreement with the literature data.  相似文献   

14.
A series of novel KBaSc2(PO4)3:Ce3+/Eu2+/Tb3+phosphors are prepared using a solid‐state reaction. X‐ray diffraction analysis and Rietveld structure refinement are used to check the phase purity and crystal structure of the prepared samples. Ce3+‐ and Eu2+‐doped phosphors both have broad excitation and emission bands, owing to the spin‐ and orbital‐allowed electron transition between the 4f and 5d energy levels. By co‐doping the KBaSc2(PO4)3:Eu2+ and KBaSc2(PO4)3:Ce3+ phosphors with Tb3+ ions, tunable colors from blue to green can be obtained. The critical distance between the Eu2+ and Tb3+ ions is calculated by a concentration quenching method and the energy‐transfer mechanism for Eu2+→Tb3+ is studied by utilizing the Inokuti–Hirayama model. In addition, the quantum efficiencies of the prepared samples are measured. The results indicate that KBaSc2(PO4)3:Eu2+,Tb3+ and KBaSc2(PO4)3:Ce3+,Tb3+ phosphors might have potential applications in UV‐excited white‐light‐emitting diodes.  相似文献   

15.
Four new three‐dimensional isostructural lanthanide–cadmium metal–organic frameworks (Ln–Cd MOFs), [LnCd2(imdc)2(Ac)(H2O)2]?H2O (Ln=Pr ( 1 ), Eu ( 2 ), Gd ( 3 ), and Tb ( 4 ); H3imdc=4,5‐imidazoledicarboxylic acid; Ac=acetate), have been synthesized under hydrothermal conditions and characterized by IR, elemental analyses, inductively coupled plasma (ICP) analysis, and X‐ray diffraction. Single‐crystal X‐ray diffraction shows that two LnIII ions are surrounded by four CdII ions to form a heteronuclear building block. The blocks are further linked to form 3D Ln–Cd MOFs by the bridging imdc3? ligand. Furthermore, the left‐ and right‐handed helices array alternatively in the lattice. Eu–Cd and Tb–Cd MOFs can emit characteristic red light with the EuIII ion and green light with the TbIII ion, respectively, while both Gd–Cd and Pr–Cd MOFs generate blue emission when they are excited. Different concentrations of Eu3+ and Tb3+ ions were co‐doped into Gd–Cd/Pr–Cd MOFs, and tunable luminescence from yellow to white was achieved. White‐light emission was obtained successfully by adjusting the excitation wavelength or the co‐doping ratio of the co‐doped Gd–Cd and Pr–Cd MOFs. These results show that the relative emission intensity of white light for Gd–Cd:Eu3+,Tb3+ MOFs is stronger than that of Pr–Cd:Eu3+,Tb3+ MOFs, which implies that the Gd complex is a better matrix than the Pr complex to obtain white‐light emission materials.  相似文献   

16.
A new family of heterometal–organic frameworks has been prepared by two synthesis strategies, in which IFMC‐26 and IFMC‐27 are constructed by self‐assembly and IFMC‐28 is obtained by stepwise synthesis based on the metalloligand (IFMC=Institute of Functional Material Chemistry). IFMC‐26 is a (3,6)‐connected net and IFMC‐27 is a (4,8)‐connected 3D framework. The metalloligands {Ni(H4L)}(NO3)2 are connected by binuclear lanthanide clusters giving rise to a 2D sheet structure in IFMC‐28 . Notably, IFMC‐26‐Eu x Tb y and IFMC‐28‐Eu x Tb y have been obtained by changing the molar ratios of raw materials. Owing to the porosity of IFMC‐26 , Tb3+@IFMC‐26‐Eu and Eu3+@IFMC‐26‐Tb are obtained by postencapsulating TbIII and EuIII ions into the pores, respectively. Tunable luminescence in metal–organic frameworks is achieved by the two kinds of doping methods. In particular, the quantum yields of heterometal–organic frameworks are apparently enhanced by postencapsulation of LnIII ions.  相似文献   

17.
The spectroscopic behavior of ionic Eu3+ or Tb3+ complexes of an aromatic carboxyl‐functionalized organic salt as well as those of the hybrid materials derived from adsorption of the ionic complexes on Laponite clay are reported. X‐ray diffraction (XRD) patterns suggest that the complexes are mainly adsorbed on the outer surfaces of the Laponite disks rather than intercalated within the interlayer spaces. Photophysical data showed that the energy‐transfer efficiency from the ligand to Eu3+ ions in the hybrid material is increased remarkably with respect to the corresponding ionic complex. The hybrid material containing the Eu3+ complex shows bright red emission from the prominent 5D07F2 transition of Eu3+ ions, and that containing the Tb3+ complex exhibits bright green emission due to the dominant 5D47F5 transition of Tb3+ ions.  相似文献   

18.
Magnetic dipole interactions are dominate in quasi one‐dimensional (1D) molecular magnetic materials, in which TbNcPc units (Tb3+=terbium(III) ion, Nc2?=naphthalocyaninato, Pc2?=phthalocyaninato) adopt a structure similar to TbPc2 single‐molecule magnets (SMMs). The magnetic properties of the [TbNcPc]0/+ (neutral 1 and cationic 2 ) with 1D structures are significantly different from those of a magnetically diluted sample ( 3 ). In particular, the magnetic relaxation time (τ) of 2 in the low‐temperature region is five orders of magnitude slower than that of 3 . Furthermore, the coercivity (HC) of 2 remained up to about 20 K. The single‐ion anisotropy of Tb3+ ions in a 1D structure and the magnetic dipole interactions acting among molecules determines the direction of the magnetic properties. These results show that the spin dynamics can be improved by manipulating the arrangement of SMMs in the solid state.  相似文献   

19.
The crystal structures of the LaIII, EuIII, and TbIII complexes of macrobicyclic [bpy.bpy.bpy] ligands, [La3+ ? 1 ]3 Cl? ( = 3- La), [Tb3+ ? 1 ]3 Cl? ( = 3- Tb), and [Eu3+ ? 2 ]3 C1? ( = 3- Eu), have been determined. They confirm the cryptate nature of these species, the cations being bound to the eight N-sites of the ligand. The macrobicycle presents two open faces, thus allowing additional coordination of two species, Cl? ions or H2O molecules, to the bound cations. These data provide structural support for the photophysical studies of the luminescent properties of the EuIII and TbIII cryptates, which indicated residual coordination of H2O molecules.  相似文献   

20.
For the first time, a new langbeinite‐type phosphate, namely potassium terbium tantalum tris(phosphate), K2Tb1.5Ta0.5(PO4)3, has been prepared successfully using a high‐temperature flux method and has been structurally characterized by single‐crystal X‐ray diffraction. The results show that its structure can be described as a three‐dimensional open framework of [Tb1.5Ta0.5(PO4)3] interconnected by K+ ions. The TbIII and TaV cations in the structure are disordered and occupy the same crystallographic sites. The IR spectrum, the UV–Vis spectrum, the morphology and the Eu3+‐activated photoluminescence spectroscopic properties were studied. A series of Eu3+‐doped phosphors, i.e. K2Tb1.5–xTa0.5(PO4)3:xEu3+ (x = 0.01, 0.03, 0.05, 0.07, 0.10), were prepared via a solid‐state reaction and the photoluminescence properties were studied. The results show that under near‐UV excitation, the luminescence colour can be tuned from green through yellow to red by simply adjusting the Eu3+ concentration from 0 to 0.1, because of the efficient Tb3+→Eu3+ energy‐transfer mechanism.  相似文献   

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