Recently,much attention has been paid to the lanthanide luminescent materials based on the visiblelight sensitization for their potential applications in the fields of bio-imaging and optical devices.In this work,the ...Recently,much attention has been paid to the lanthanide luminescent materials based on the visiblelight sensitization for their potential applications in the fields of bio-imaging and optical devices.In this work,the lanthanide complexes have been covalently bonded to the ordered mesoporous titania（OMT） matrix,and the resulting titania-based hybrid ordered mesoporous materials（named as LnDBOMT,Ln = Eu,Sm,Yb,Nd） were characterized by using Fourier-transform infrared（FT-IR） spectroscopy,small-angle X-ray powder diffraction（SAXD）,N2 adsorption-desorption isotherms,transmission electron microscopy（TEM）,fluorescence spectroscopy,and thermogravimetric analysis.Generally,exciting with visible light is advantageous over UV excitation.Of importance here is that,under excitation with visible light,the LnDB-OMT all show characteristic visible（Eu3＋,Sm3＋） as well as nearinfrared（Sm3＋,Yb3＋,Nd3＋） luminescence of the corresponding Ln3＋ ions（multicolor emission covered from 500 to 1400 nm spectral region）,which is attributed to the energy transfer from the ligands to the Ln3＋ ions via an antenna effect.展开更多
Six new lanthanide complexes:[Ln(3,4-DEOBA)3(4,4'-DM-2,2'-bipy)]2·2C_(2)H_(5)OH,[Ln=Dy(1),Eu(2),Tb(3),Sm(4),Ho(5),Gd(6);3,4-DEOBA-=3,4-diethoxybenzoate,4,4'-DM-2,2'-bipy=4,4'-dimethyl-2,2'...Six new lanthanide complexes:[Ln(3,4-DEOBA)3(4,4'-DM-2,2'-bipy)]2·2C_(2)H_(5)OH,[Ln=Dy(1),Eu(2),Tb(3),Sm(4),Ho(5),Gd(6);3,4-DEOBA-=3,4-diethoxybenzoate,4,4'-DM-2,2'-bipy=4,4'-dimethyl-2,2'-bipyridine]were successfully synthesized by the volatilization of the solution at room temperature.The crystal structures of six complexes were determined by single-crystal X-ray diffraction technology.The results showed that the complexes all have a binuclear structure,and the structures contain free ethanol molecules.Moreover,the coordination number of the central metal of each structural unit is eight.Adjacent structural units interact with each other through hydrogen bonds and further expand to form 1D chain-like and 2D planar structures.After conducting a systematic study on the luminescence properties of complexes 1-4,their emission and excitation spectra were obtained.Experimental results indicated that the fluorescence lifetimes of complexes 2 and 3 were 0.807 and 0.845 ms,respectively.The emission spectral data of complexes 1-4 were imported into the CIE chromaticity coordinate system,and their corre sponding luminescent regions cover the yellow light,red light,green light,and orange-red light bands,respectively.Within the temperature range of 299.15-1300 K,the thermal decomposition processes of the six complexes were comprehensively analyzed by using TG-DSC/FTIR/MS technology.The hypothesis of the gradual loss of ligand groups during the decomposition process was verified by detecting the escaped gas,3D infrared spectroscopy,and ion fragment information detected by mass spectrometry.The specific decomposition path is as follows:firstly,free ethanol molecules and neutral ligands are removed,and finally,acidic ligands are released;the final product is the corresponding metal oxide.CCDC:2430420,1;2430422,2;2430419,3;2430424,4;2430421,5;2430423,6.展开更多
Partitioning of actinides from lanthanides is pivotal for advancing nuclear waste management and sustaining nuclear energy development,yet it remains a formidable challenge due to the intricate chemical behaviors of t...Partitioning of actinides from lanthanides is pivotal for advancing nuclear waste management and sustaining nuclear energy development,yet it remains a formidable challenge due to the intricate chemical behaviors of these f-block elements.In this study,we introduce 3,6-di-2-pyridyl-1,2,4,5-tetrazine(L1),whose hydrolysis product of pyridine-2-carbox-aldehyde(pyridine-2-carbonyl)-hydrazone(L2)can fractionally crystallize U(Ⅵ)ions over Ln(Ⅲ)cations with high selectivity and efficiency.Through hydrolysis-induced C–N bond cleavage,L2 acts as a tetradentate ligand,coordinating with two UO_(2)^(2+) ions in a planar arrangement to form a zerodimensional cluster,[(UO_(2))2(μ_(3)-O)(L2)(CH_(3)COO)]·DMF(U-L2),while lanthanide ions(Ln=La,Pr,Nd,Sm,Eu,Gd,Tb,Yb,and Lu)remain in solution due to their inability to achieve similar coordination.This selective crystallization strategy yields exceptional separation factors(SFs)between U(Ⅵ)and Ln(Ⅲ),with a value of 756276 between U(Ⅵ)and Sm(Ⅲ),the highest reported to date.Furthermore,this fractional crystallization separation process can be achieved under mild ambient conditions with high SFs,enabling the development of a rapid,safe and energy-efficient strategy for once-through separation of high oxidation state actinides from lanthanides.展开更多
Given customizable crystal structure and intriguing optical properties,lanthanide titanium-oxygen clusters(LTOCs)with atomic-level accuracy have gained a lot of interest.In this study,we prepared[Ln_(9)Ti_(2)(μ4-O)(...Given customizable crystal structure and intriguing optical properties,lanthanide titanium-oxygen clusters(LTOCs)with atomic-level accuracy have gained a lot of interest.In this study,we prepared[Ln_(9)Ti_(2)(μ4-O)(μ3-OH)_(14)(acac)_(17)(CH_(3)O)_(2)(CH_(3)OH)_(3)](Ln=Tb_(x)Eu_(9−x)(x=0,4,6,7,8,9),Hacac=acetylacetone),Tb^(3+)and Eu^(3+)co-doped LTOCs,to modify the optical properties for the luminescence thermometer.In detail,the serial LTOCs display dual characteristic emission peaks of ^(5)D_(4)→^(7)F_(5) for Tb^(3+)and^(5)D_(0)→^(7)F_(2) for Eu^(3+)at 548 and 616 nm,respectively,under 330 nm excitation.Effective energy transfer(ET)between Tb^(3+)ions and Eu^(3+)ions was revealed in terms of both emission spectra and luminescence lifetime.The ^(5)D_(0)→^(7)F_(2) emission intensity of Eu^(3+)ions at 616 nm is maximally enhanced(by a factor of 11.2)with a change in the relative molar ratio of Tb^(3+)to Eu^(3+),along with a change in the ET efficiency of Tb^(3+)→Eu^(3+).In addition,the luminescent color changes from red,orange,yellow,to green.This precise control of the ET process between rare-earth ions allows{Tb_(6)Eu_(3)Ti_(2)}to reach a maximum relative sensitivity of 1.241 K^(−1) at 355 K,which is an enhancement of up to 4.6-fold with respect to the previously reported homonuclear emission,holding great potential in the optical thermometers.展开更多
Two novel lanthanide complexes,[Sm_(2)(BA)_(6)(4-OH-terpy)_(2)]·2H_(2)O·2EtOH(1)and[Pr_(2)(BA)_(6)(4-OH-terpy)_(2)(H_(2)O)_(2)]·HBA·H_(2)O(2),where HBA=benzoic acid,4-OH-terpy=4-hydroxy-2,2'∶6...Two novel lanthanide complexes,[Sm_(2)(BA)_(6)(4-OH-terpy)_(2)]·2H_(2)O·2EtOH(1)and[Pr_(2)(BA)_(6)(4-OH-terpy)_(2)(H_(2)O)_(2)]·HBA·H_(2)O(2),where HBA=benzoic acid,4-OH-terpy=4-hydroxy-2,2'∶6',2″-terpyridine,were successfully synthesized using ultrasonic dissolution and the conventional solution method with two mixed ligands HBA and 4-OH-terpy.During the synthesis,4-OH-terpy was involved in the reaction as a neutral ligand,while HBA,in its deprotonated form(BA-),coordinated with the lanthanide ions as an acidic ligand.The crystal structures of these two complexes were precisely determined by single-crystal X-ray diffraction.Elemental analysis,infrared and Raman spectroscopy,and powder X-ray diffraction techniques were also employed to further explore the physicochemical properties of the two complexes.The single-crystal X-ray diffraction data indicate that,despite their structural differences,both complexes belong to the triclinic crystal system P1 space group.The central lanthanide ions have the same coordination number but exhibit different coordination environments.To comprehensively evaluate the thermal stability of these two complexes,comprehensive tests including thermogravimetric analysis,differential thermogravimetric analysis,differential scanning calorimetry,Fourier transform infrared spectroscopy,and mass spectrometry were conducted.Meanwhile,an in-depth investigation was conducted into the 3D infrared stacked images and mass spectra of the gases emitted from the complexes.In addition,studies of the fluorescence properties of complex1 showed that it exhibited fluorescence emission matching the Sm^(3+)characteristic transition.展开更多
The dominant oxidation state for lanthanide ions is+3 due to the loss of 5d and 6s electrons from their shared configuration of[Xe]4f^(0-14)5d^(0-16)s(2).There are however several exceptions because of the completely ...The dominant oxidation state for lanthanide ions is+3 due to the loss of 5d and 6s electrons from their shared configuration of[Xe]4f^(0-14)5d^(0-16)s(2).There are however several exceptions because of the completely empty(Ce(Ⅳ)),half-filled(Eu(Ⅱ)),or fully filled(Yb(Ⅱ))4f subshell.As such,stable complexes are formed primarily with Ln(Ⅲ)ions[1].展开更多
The dynamic regulation of single-molecule magnet(SMM)behavior remains challenging but extremely critical to practical applications.Efficient manipulation of magnetization of complexes via external stimulus,like solven...The dynamic regulation of single-molecule magnet(SMM)behavior remains challenging but extremely critical to practical applications.Efficient manipulation of magnetization of complexes via external stimulus,like solvent,pressure,electric potential or light may further extend the scope of applications for these magnetic molecules.Among these,light is highly desirable because it can provide high-contrast,sensitive and remote control of magnetic behavior at relatively high spatial and temporal resolution.Lanthanide(Ln)complexes represent a distinctive platform for constructing photo-responsive SMMs owing to their extreme sensitivity to subtle change of crystal field(CF)environment.Despite the numerous potential benefits and unique advantages outlined above,light control of magnetism of Ln-SMMs still faces several challenges.This review briefly summarizes recent advancements of photo-responsive Ln-SMMs with photochromic characteristic,highlighting the significance of photoinduced structural changes or electronic distribution alterations to modulate the magnetic properties,which may throw light on the future improvements of photo-responsive molecular materials.展开更多
Rare-earth supramolecular compounds,such as lanthanide organic polyhedrons(LOPs),are of particular interest due to their many possible applications in various fields.Here we report the first syntheses of Ln_(4)(L^(...Rare-earth supramolecular compounds,such as lanthanide organic polyhedrons(LOPs),are of particular interest due to their many possible applications in various fields.Here we report the first syntheses of Ln_(4)(L^(·+))_(4)-type(Ln,lanthanides;L^(·+),radical ligand)radical-bridged lanthanide organic tetrahedrons by self-assembly of face-capping triphenylamine(TPA)-cored radical ligand with different lanthanide ions.Remarkable coordination enhanced radical stability has been observed,with half-life times(t_(1/2))for L_(1)^(·+),La_(4)(L_(1)^(·+))_(4),Eu_(4)(L_(1)^(·+))_(4),Gd_(4)(L_(1)^(·+))_(4),Tb_(4)(L_(1)^(·+))_(4)and Lu_(4)(L_(1)^(·+))_(4)estimated to be 53 min,482 min,624 min,1248 min,822 min and 347 min,respectively.The TPA radical in Ln_(4)(L_(1)^(·+))_(4)containing paramagnetic Ln ions(Ln=Eu^(Ⅲ),Gd^(Ⅲ)and Tb^(Ⅲ))is observed to be more stable than that in Ln_(4)(L_(1)^(·+))_(4)(Ln=La^(Ⅲ)and Lu^(Ⅲ))constructed by diamagnetic Ln ions.This difference in radical stability is possibly due to the magnetic interactions between paramagnetic Ln^(Ⅲ)ions and L_(1)^(·+)ligands,as confirmed by electron paramagnetic resonance(EPR)in La_(4)(L)_(4)(L=L_(1)and L_(1)^(·+))and Tb_(4)(L)_(4)(L=L_(1)and L_(1)^(·+)),and magnetic susceptibility measurements in Tb·_(4)(L)_(4)(L=L_(1)and L_(1)^(·+)).Our study reveals the coordination of radical ligands with lanthanide ions can improve the radical stability,which is crucial for their applications.展开更多
Lanthanide-sensitized upconverting nanoparticles(UCNPs)are widely studied because of their unusual optical characteristics,such as large antenna-generated anti-Stokes shifts,high photostability,and narrow emission ban...Lanthanide-sensitized upconverting nanoparticles(UCNPs)are widely studied because of their unusual optical characteristics,such as large antenna-generated anti-Stokes shifts,high photostability,and narrow emission bandwidths,which can be harnessed for a variety of applications including bioimaging,sensing,information security and high-level anticounterfeiting.The diverse requirements of these applications typically require precise control over upconversion luminescence(UCL).Recently,the concept of energy migration upconversion has emerged as an effective approach to modulate UCL for various lanthanide ions.Moreover,it provides valuable insights into the fundamental comprehension of energy transfer mechanisms on the nanoscale,thereby contributing to the design of efficient lanthanide-sensitized UCNPs and their practical applications.Here we present a comprehensive overview of the latest developments in energy migration upconversion in lanthanide-sensitized nanoparticles for photon upconversion tuning,encompassing design strategies,mechanistic investigations and applications.Additionally,some future prospects in the field of energy migration upconversion are also discussed.展开更多
Volatile organic compounds(VOCs)are significant indoor and outdoor air pollutants.Thermocatalysis is one of the most common methods for their removal,capable of completely mineralizing VOCs.Nanomaterials derived by py...Volatile organic compounds(VOCs)are significant indoor and outdoor air pollutants.Thermocatalysis is one of the most common methods for their removal,capable of completely mineralizing VOCs.Nanomaterials derived by pyrolytic means,based on the high specific surface area and high tunability of metal-organic frameworks(MOFs),have received increasing attention in the field of efficient catalysis of VOCs.Lanthanide metal-organic frameworks(Ln-MOFs)have significant research value in thermocatalytic applications for VOCs by virtue of their flexible and rich coordination behaviors,Lewis acidity,excellent oxygen storage and discharge capabilities,unique electronic structure properties of lanthanide coordination metals.Herein,a comprehensive review of the recent advances in Ln-MOF-based catalysts for thermally catalyzed VOCs elaborates on the effects based on the structure,including pyrolysis strategy,metal substitution,surface modification,and composite doping.The review addresses the mechanistic issues of Ln-MOF-based catalysts in the thermocatalysis of VOCs and highlights their characteristic advantages as efficient catalysts for VOCs.Finally,this review also summarizes the key issues and challenges,provides perspectives and outlooks on the development and design of Ln-MOFbased catalysts.It serves as a reference for enhancing the performance and selecting appropriate LnMOF-based catalysts for treating VOCs.展开更多
Metal-organic frameworks(MOFs)usually exist in the state of powder or crystal.When they are exposed to hydrophilic solvents,their structure will change and become unstable.Therefore,it is a challenge to construct MOF ...Metal-organic frameworks(MOFs)usually exist in the state of powder or crystal.When they are exposed to hydrophilic solvents,their structure will change and become unstable.Therefore,it is a challenge to construct MOF materials with tunable mechanical properties.Herein,we report in-situ growth lanthanide metal-organic framework(LnMOF)in sodium alginate(SA)and polyvinyl alcohol(PVA)hydrogel matrix.The prepared composite hydrogel not only displays characteristic lanthanide narrow-band emission under ultraviolet light,but also demonstrates excellent mechanical properties.The addition of LnMOF significantly enhances the compressive strength of the hydrogel(from 0.75 to 7.32 MPa).Furthermore,the composite hydrogel shows highly selective recognition of glutaraldehyde and gaseous formaldehyde at room temperature.The detection limits(LOD)of SP-EuMOF for glutaraldehyde and formaldehyde are 0.27 and 0.22 ppm,respectively.Based on these results,the LnMOF composite hydrogel is deemed to have significant potential as a fluorescent sensor for both glutaraldehyde and formaldehyde detection.展开更多
Two novel lanthanide-based coordination complexes,[LaL(Phen)(NO_(3))_(3)]n(1)and[Pr_(2)L_(2)(Phen)2(NO_(3))_(6)]n(2),were synthesized via a stoichiometric 1∶1∶1 reaction of lanthanide nitrates with tetraisopropyl 1,...Two novel lanthanide-based coordination complexes,[LaL(Phen)(NO_(3))_(3)]n(1)and[Pr_(2)L_(2)(Phen)2(NO_(3))_(6)]n(2),were synthesized via a stoichiometric 1∶1∶1 reaction of lanthanide nitrates with tetraisopropyl 1,2-ethylenediphosphate(L)and 1,10-phenanthroline(Phen)in a mixed ethanol-acetonitrile solvent system at room temperature.Their structures were determined by single-crystal X-ray diffraction(SCXRD)and further confirmed by infrared spectroscopy and elemental analysis.Thermogravimetric analysis(TGA)was used to assess thermal stability.Complexes 1 and 2 are both composed of O atoms provided by L and nitrate ions,formed a 10-coordinate configuration with the central Ln^(3+)(Ln=La,Pr)ion.Complex 1 forms a one-dimensional infinite chain connected by bridging ligands and constructs a complex three-dimensional stacking structure through hydrogen bonding andπ…πweak interactions.Complex 2 is connected by ligand L to form a one-dimensional infinite chain and through weak forces such as hydrogen bonding and C-H…πbonds,a novel three-dimensional stacking structure is formed by transverse and longitudinal crossing.展开更多
Mixed-lanthanide(Ln) luminescent materials have important application values in ratiometric temperature sensing.Hydrogen-bonded organic frameworks(HOFs) offer a self-supporting network to conveniently tune multiple Ln...Mixed-lanthanide(Ln) luminescent materials have important application values in ratiometric temperature sensing.Hydrogen-bonded organic frameworks(HOFs) offer a self-supporting network to conveniently tune multiple Ln^(3+)ions,but challenges still exist in material design.In this work,we selected two simple organic molecules as hydrogen-bonded building blocks,which are melamine(MA) and 2,5-pyridinedicarboxylic acid(PDC) owning the suitable energy to sensitize Tb^(3+)and Eu^(3+)ions.MA assists PDC molecules to support the network in a new HOF(MA-PDC),where the abundant carboxylic groups enable Ln^(3+)ions to combine with the HOF.Based on the effective energy transfer process,the emission of Tb^(3+)and Eu^(3+)from TbxEu1-x@MA-PDC(x=0.75,0.85,0.90) shows the obvious temperature dependence,which benefits ratiometric temperature detection.Taking Tb0.85Eu0.15@MA-PDC as an example,when temperature varies from 303 to 443 K,the intensity ratio exhibits distinct S-type response based on Mott-Seitz model.It also behaves good relative sensitivity(1.03%/K at 383 K),low temperature resolution(0.059 K) and large reproducibility(>96%).This work demonstrates that functionalization of a simple-component HOF with mixed Ln^(3+)ions is a fantastic strategy to develop novel ratiometric thermometers of both low cost and good performance.展开更多
Scientists have devoted considerable effort overs several decades to reduce automobile exhaust emissions,and one practical and important strategy is the catalytic conversion of nitric oxide(NO)[1].Previous studies hav...Scientists have devoted considerable effort overs several decades to reduce automobile exhaust emissions,and one practical and important strategy is the catalytic conversion of nitric oxide(NO)[1].Previous studies have shown that lanthanide(Ln)metals can catalytically reduce NO.Thus,the reactions of NO with Ln to form lanthanide-nitric oxide(LnNO)complexes have been designed and served as the simplest prototype molecules for studying NO chemisorption on metal surfaces[2].展开更多
Interest in lanthanide complexes in the synthetic clays remains growing considerably during the last decades because of the attractive features of the individuals. Synthetic clays like Laponite~? and Aminoclay show gr...Interest in lanthanide complexes in the synthetic clays remains growing considerably during the last decades because of the attractive features of the individuals. Synthetic clays like Laponite~? and Aminoclay show great potentials in building up the luminescent hybrid materials due to their obvious advantages such as high purity, high dispersibility(or solubility) in water to yield translucent gels and clear aqueous solution. Additionally, their strong adsorption capacity for non-polar molecules or complexes is favorable to the formation of water-soluble and aqueous processable luminescent materials. This feature article summarizes the latest developments in the design and preparation of highly luminescent organicinorganic hybrid materials with excellent aqueous process ability based on lanthanide complexes intercalated synthetic clays.展开更多
Present-day advanced technologies heavily rely on the exciting magnetic and spectroscopic properties of lanthanide ions. In particular, their ability to generate well-characterized and intense near-infrared (NIR) lumi...Present-day advanced technologies heavily rely on the exciting magnetic and spectroscopic properties of lanthanide ions. In particular, their ability to generate well-characterized and intense near-infrared (NIR) luminescence is exploited in any modern fiber-optic telecommunication network. In this feature article, we first summarize the whereabouts underlying the design of highly luminescent NIR molecular edifices and materials. We then focus on describing the main trends in three applications related to this spectral range: telecommunications, biosciences, and solar energy conversion. In telecommunications, efforts concentrate presently on getting easily processable polymer-based waveguide amplifiers. Upconversion nanophosphors emitting in the visible after NIR excitation are now ubiquitous in many bioanalyses while their application to bio-imaging is still in its early stages; however, highly sensitive NIR-NIR systems start to be at hand for both in vitro and in vivo imaging, as well as dual probes combining magnetic resonance and optical imaging. Finally, both silicon-based and dye-sensitized solar cells benefit from the downconversion and upconversion capabilities of lanthanide ions to harvest UV and NIR solar light and to boost the overall quantum efficiency of these next-generation devices.展开更多
Calcium tungstate phosphors activated by the Ln3＋ ions （Ln-Pr, Nd, Tb, Yb） were synthesized by a traditional high-temperature solid-state method. The crystal structures and morphologies of the products were charact...Calcium tungstate phosphors activated by the Ln3＋ ions （Ln-Pr, Nd, Tb, Yb） were synthesized by a traditional high-temperature solid-state method. The crystal structures and morphologies of the products were characterized by scanning electron microscopy （SEM）, X-ray powders diffraction （XRD） and infrared spectra （FT-1R）. The samples were fotmd to show luminescence properties （down-conversion, DC, at excitation wavelength 254 nm and up-conversion, UC, at excitation wavelength 980 nm）. CaWO4 doped with Tb3＋/yb3＋ showed green DC and UC luminescence characteristic of Tb（Ⅲ） ion in the range of 470-660 nm, cor- responding to the 5D4→7F6,5,4,3,2 electronic transition. CaWO4 doped with Pr3＋/Yb3＋ showed week blue, green and red （DC and UC） luminescence of Pr（Ⅲ） ion, in the wavelength region of 450-700 nm. Emission peaks were ascribed to the 3P1→3H4,5,6, 3P0→3H4,5,6, 3P1→3F2 and 3P0→3F2 transitions, respectively. CaWO4 doped with Nd3＋/yb3＋ phosphor emitted orange UC luminescence at 450-690 nm （2p3/2→4I15/2, 4G7/2→419/2,11/2,13/2） and strong near-infrared UC luminescence at 720-900 nm （4F7/2＋4S3/2→4419/2, 4F5/2＋2H3/2→419/2, 4F3/2→4I9/2） which is the characteristic of Nd（Ⅲ） ion.展开更多
The complexes of rare earth elements with 1,2-diphenyl-4-butyl-3,5-Pyrazolidinedione （PBH, phenylbutazone） were synthesized and characterized by elemental analysis, molar conductance, IR, UV-Vis, EPR and magnetic mo...The complexes of rare earth elements with 1,2-diphenyl-4-butyl-3,5-Pyrazolidinedione （PBH, phenylbutazone） were synthesized and characterized by elemental analysis, molar conductance, IR, UV-Vis, EPR and magnetic moment measurements. Based on these studies the complexes were formulated as [Ln（PB）3（H2O）2].nH2O, where Ln=Eu（III）, Gd（III）, Tb（III）, Dy（III） and Er（III）. From IR spectra, it was found that PBH acted as a bidentate mono-ionic ligand coordinating through two carbonyl oxygen of the pyrazolidinedione ring. The thermal analysis of all the complexes was carried out at a heating rate of 10 oC/min. The kinetic aspects of the complexes were evaluated. The nega-tive entropy value of the complexes indicated a more ordered state for the activated complexes. The photoluminescence property of Tb（III） complex was investigated. It showed all the characteristic emission peaks of Tb^3＋ with a life time of 0.98914 ms.展开更多
Photoluminescent hybrid materials containing carboxymethyl cellulose and lanthanide ions（Eu3＋, Tb3＋）were prepared by a facile method under ambient conditions. Lanthanide ions were covalently grafted to the cellulo...Photoluminescent hybrid materials containing carboxymethyl cellulose and lanthanide ions（Eu3＋, Tb3＋）were prepared by a facile method under ambient conditions. Lanthanide ions were covalently grafted to the cellulose framework through coordination with the carboxylic groups of the cellulose. Hybrid materials were fabricated as hydrogel and aerogel. As shown by SEM and pore parameters, aerogel materials which were obtained by supercritical CO2 drying show hierarchical porous structure. The photoluminescence spectrum of the hybrid materials shows the characteristic red emission of Eu3＋ ion and green emission of Tb3＋. Further luminescent investigations reveal that these hybrid materials can detect Fe3＋ with relative selectivity and high sensitivity, which suggests that the hybrid materials could be a promising luminescent probe for selectively sensing Fe3＋ ion.展开更多
Trivalent lanthanide ions display fascinating optical properties. The discovery of the corresponding elements and their first industrial uses were intimately linked to their optical properties. This relationship has b...Trivalent lanthanide ions display fascinating optical properties. The discovery of the corresponding elements and their first industrial uses were intimately linked to their optical properties. This relationship has been kept alive until today when many high-technology applications of lanthanide-containing materials such as energy-saving lighting devices, displays, optical fibers and amplifiers, lasers, responsive luminescent stains for biomedical analyses and in cellulo sensing and imaging, heavily rely on the brilliant and pure-color emission of lanthanide ions. In this review we first outlined the basics of lanthanide luminescence with emphasis on f-f transitions, the sensitization mechanisms, and the assessment of the luminescence efficiency of lanthanide-containing emissive molecular edifices. Emphasis was then put on two fast developing aspects of lanthanide luminescence： materials for telecommunications and light emitting diodes, and biomedical imaging and sensing. Recent advances in NIR-emitting materials for plastic amplifiers and waveguides were described, together with the main solutions brought by researchers to minimize non-radiative deactivation of excited states. The demonstration in 1999 that erbium tris（8-hydroxyquinolinate） displayed a bright green emission suitable for organic light emitting diodes （OLEDs） was followed by realizing that in OLEDs, 25% of the excitation energy leads to singlet states and 75% to triplet states. Since lanthanide ions are good triplet quenchers, they now also play a key role in the development of these lighting devices. Luminescence analyses of biological molecules are among the most sensitive analytical techniques known. The long lifetime of the lanthanide excited states allows time-resolved spectroscopy to be used, suppressing the sample autofluorescence and reaching very low detection limits. Not only visible lanthanide sensors are now ubiquitously provided in medical diagnosis and in cell imaging, but the feasibility of using NIR emission of ions such as YbⅢ is now being tested because of deeper penetration in biological tissues.展开更多
基金Project supported by the National Natural Science Foundation of China(21571125,21471144)National Key R&D Program of China(2016YFE0114800)the project from State Key Laboratory of Rare Earth Resource Utilization(RERU2016013)
文摘Recently,much attention has been paid to the lanthanide luminescent materials based on the visiblelight sensitization for their potential applications in the fields of bio-imaging and optical devices.In this work,the lanthanide complexes have been covalently bonded to the ordered mesoporous titania（OMT） matrix,and the resulting titania-based hybrid ordered mesoporous materials（named as LnDBOMT,Ln = Eu,Sm,Yb,Nd） were characterized by using Fourier-transform infrared（FT-IR） spectroscopy,small-angle X-ray powder diffraction（SAXD）,N2 adsorption-desorption isotherms,transmission electron microscopy（TEM）,fluorescence spectroscopy,and thermogravimetric analysis.Generally,exciting with visible light is advantageous over UV excitation.Of importance here is that,under excitation with visible light,the LnDB-OMT all show characteristic visible（Eu3＋,Sm3＋） as well as nearinfrared（Sm3＋,Yb3＋,Nd3＋） luminescence of the corresponding Ln3＋ ions（multicolor emission covered from 500 to 1400 nm spectral region）,which is attributed to the energy transfer from the ligands to the Ln3＋ ions via an antenna effect.
文摘Six new lanthanide complexes:[Ln(3,4-DEOBA)3(4,4'-DM-2,2'-bipy)]2·2C_(2)H_(5)OH,[Ln=Dy(1),Eu(2),Tb(3),Sm(4),Ho(5),Gd(6);3,4-DEOBA-=3,4-diethoxybenzoate,4,4'-DM-2,2'-bipy=4,4'-dimethyl-2,2'-bipyridine]were successfully synthesized by the volatilization of the solution at room temperature.The crystal structures of six complexes were determined by single-crystal X-ray diffraction technology.The results showed that the complexes all have a binuclear structure,and the structures contain free ethanol molecules.Moreover,the coordination number of the central metal of each structural unit is eight.Adjacent structural units interact with each other through hydrogen bonds and further expand to form 1D chain-like and 2D planar structures.After conducting a systematic study on the luminescence properties of complexes 1-4,their emission and excitation spectra were obtained.Experimental results indicated that the fluorescence lifetimes of complexes 2 and 3 were 0.807 and 0.845 ms,respectively.The emission spectral data of complexes 1-4 were imported into the CIE chromaticity coordinate system,and their corre sponding luminescent regions cover the yellow light,red light,green light,and orange-red light bands,respectively.Within the temperature range of 299.15-1300 K,the thermal decomposition processes of the six complexes were comprehensively analyzed by using TG-DSC/FTIR/MS technology.The hypothesis of the gradual loss of ligand groups during the decomposition process was verified by detecting the escaped gas,3D infrared spectroscopy,and ion fragment information detected by mass spectrometry.The specific decomposition path is as follows:firstly,free ethanol molecules and neutral ligands are removed,and finally,acidic ligands are released;the final product is the corresponding metal oxide.CCDC:2430420,1;2430422,2;2430419,3;2430424,4;2430421,5;2430423,6.
基金supported by the National Natural Science Foundation of China(U22B20139,22322609,22076152,and 22476158).
文摘Partitioning of actinides from lanthanides is pivotal for advancing nuclear waste management and sustaining nuclear energy development,yet it remains a formidable challenge due to the intricate chemical behaviors of these f-block elements.In this study,we introduce 3,6-di-2-pyridyl-1,2,4,5-tetrazine(L1),whose hydrolysis product of pyridine-2-carbox-aldehyde(pyridine-2-carbonyl)-hydrazone(L2)can fractionally crystallize U(Ⅵ)ions over Ln(Ⅲ)cations with high selectivity and efficiency.Through hydrolysis-induced C–N bond cleavage,L2 acts as a tetradentate ligand,coordinating with two UO_(2)^(2+) ions in a planar arrangement to form a zerodimensional cluster,[(UO_(2))2(μ_(3)-O)(L2)(CH_(3)COO)]·DMF(U-L2),while lanthanide ions(Ln=La,Pr,Nd,Sm,Eu,Gd,Tb,Yb,and Lu)remain in solution due to their inability to achieve similar coordination.This selective crystallization strategy yields exceptional separation factors(SFs)between U(Ⅵ)and Ln(Ⅲ),with a value of 756276 between U(Ⅵ)and Sm(Ⅲ),the highest reported to date.Furthermore,this fractional crystallization separation process can be achieved under mild ambient conditions with high SFs,enabling the development of a rapid,safe and energy-efficient strategy for once-through separation of high oxidation state actinides from lanthanides.
基金supported by the National Natural Science Foundation of China(Nos.12174151 and 12304448)the Specific Research Fund of the Innovation Platform for Academicians of Hainan Province(No.YSPTZX202208)+3 种基金Hainan Province Clinical Medical Center(No.QWYH_(2)022341)the Key Laboratory of New Energy and Rare Earth Resource Utilization of the State People’s Committee of China(No.NERE202206)the Department of Science and Technology of Jilin Province(No.20220101059JC)the Key Laboratory of the Ministry of Education for First Aid and Trauma Research(No.KLET-202218).
文摘Given customizable crystal structure and intriguing optical properties,lanthanide titanium-oxygen clusters(LTOCs)with atomic-level accuracy have gained a lot of interest.In this study,we prepared[Ln_(9)Ti_(2)(μ4-O)(μ3-OH)_(14)(acac)_(17)(CH_(3)O)_(2)(CH_(3)OH)_(3)](Ln=Tb_(x)Eu_(9−x)(x=0,4,6,7,8,9),Hacac=acetylacetone),Tb^(3+)and Eu^(3+)co-doped LTOCs,to modify the optical properties for the luminescence thermometer.In detail,the serial LTOCs display dual characteristic emission peaks of ^(5)D_(4)→^(7)F_(5) for Tb^(3+)and^(5)D_(0)→^(7)F_(2) for Eu^(3+)at 548 and 616 nm,respectively,under 330 nm excitation.Effective energy transfer(ET)between Tb^(3+)ions and Eu^(3+)ions was revealed in terms of both emission spectra and luminescence lifetime.The ^(5)D_(0)→^(7)F_(2) emission intensity of Eu^(3+)ions at 616 nm is maximally enhanced(by a factor of 11.2)with a change in the relative molar ratio of Tb^(3+)to Eu^(3+),along with a change in the ET efficiency of Tb^(3+)→Eu^(3+).In addition,the luminescent color changes from red,orange,yellow,to green.This precise control of the ET process between rare-earth ions allows{Tb_(6)Eu_(3)Ti_(2)}to reach a maximum relative sensitivity of 1.241 K^(−1) at 355 K,which is an enhancement of up to 4.6-fold with respect to the previously reported homonuclear emission,holding great potential in the optical thermometers.
文摘Two novel lanthanide complexes,[Sm_(2)(BA)_(6)(4-OH-terpy)_(2)]·2H_(2)O·2EtOH(1)and[Pr_(2)(BA)_(6)(4-OH-terpy)_(2)(H_(2)O)_(2)]·HBA·H_(2)O(2),where HBA=benzoic acid,4-OH-terpy=4-hydroxy-2,2'∶6',2″-terpyridine,were successfully synthesized using ultrasonic dissolution and the conventional solution method with two mixed ligands HBA and 4-OH-terpy.During the synthesis,4-OH-terpy was involved in the reaction as a neutral ligand,while HBA,in its deprotonated form(BA-),coordinated with the lanthanide ions as an acidic ligand.The crystal structures of these two complexes were precisely determined by single-crystal X-ray diffraction.Elemental analysis,infrared and Raman spectroscopy,and powder X-ray diffraction techniques were also employed to further explore the physicochemical properties of the two complexes.The single-crystal X-ray diffraction data indicate that,despite their structural differences,both complexes belong to the triclinic crystal system P1 space group.The central lanthanide ions have the same coordination number but exhibit different coordination environments.To comprehensively evaluate the thermal stability of these two complexes,comprehensive tests including thermogravimetric analysis,differential thermogravimetric analysis,differential scanning calorimetry,Fourier transform infrared spectroscopy,and mass spectrometry were conducted.Meanwhile,an in-depth investigation was conducted into the 3D infrared stacked images and mass spectra of the gases emitted from the complexes.In addition,studies of the fluorescence properties of complex1 showed that it exhibited fluorescence emission matching the Sm^(3+)characteristic transition.
基金supported by the National Natural Science Foundation of China(22101116,92261203,21971106)Shenzhen Fundamental Research Program(JCYJ20220530115001002 and JCYJ20220818100417037).
文摘The dominant oxidation state for lanthanide ions is+3 due to the loss of 5d and 6s electrons from their shared configuration of[Xe]4f^(0-14)5d^(0-16)s(2).There are however several exceptions because of the completely empty(Ce(Ⅳ)),half-filled(Eu(Ⅱ)),or fully filled(Yb(Ⅱ))4f subshell.As such,stable complexes are formed primarily with Ln(Ⅲ)ions[1].
基金financially supported by the Fundamental Research Program of Shanxi Province(No.202303021222126)the National Natural Science Foundation of China(No.92261103)。
文摘The dynamic regulation of single-molecule magnet(SMM)behavior remains challenging but extremely critical to practical applications.Efficient manipulation of magnetization of complexes via external stimulus,like solvent,pressure,electric potential or light may further extend the scope of applications for these magnetic molecules.Among these,light is highly desirable because it can provide high-contrast,sensitive and remote control of magnetic behavior at relatively high spatial and temporal resolution.Lanthanide(Ln)complexes represent a distinctive platform for constructing photo-responsive SMMs owing to their extreme sensitivity to subtle change of crystal field(CF)environment.Despite the numerous potential benefits and unique advantages outlined above,light control of magnetism of Ln-SMMs still faces several challenges.This review briefly summarizes recent advancements of photo-responsive Ln-SMMs with photochromic characteristic,highlighting the significance of photoinduced structural changes or electronic distribution alterations to modulate the magnetic properties,which may throw light on the future improvements of photo-responsive molecular materials.
基金supported by National Key Research and Development Program of China(Nos.2021YFA1500400 and 2022YFA1503300)the National Natural Science Foundation of China(Nos.21825107,21971237,22171264 and 22301301)the Science Foundation of the Fujian Province(No.2021J02016)。
文摘Rare-earth supramolecular compounds,such as lanthanide organic polyhedrons(LOPs),are of particular interest due to their many possible applications in various fields.Here we report the first syntheses of Ln_(4)(L^(·+))_(4)-type(Ln,lanthanides;L^(·+),radical ligand)radical-bridged lanthanide organic tetrahedrons by self-assembly of face-capping triphenylamine(TPA)-cored radical ligand with different lanthanide ions.Remarkable coordination enhanced radical stability has been observed,with half-life times(t_(1/2))for L_(1)^(·+),La_(4)(L_(1)^(·+))_(4),Eu_(4)(L_(1)^(·+))_(4),Gd_(4)(L_(1)^(·+))_(4),Tb_(4)(L_(1)^(·+))_(4)and Lu_(4)(L_(1)^(·+))_(4)estimated to be 53 min,482 min,624 min,1248 min,822 min and 347 min,respectively.The TPA radical in Ln_(4)(L_(1)^(·+))_(4)containing paramagnetic Ln ions(Ln=Eu^(Ⅲ),Gd^(Ⅲ)and Tb^(Ⅲ))is observed to be more stable than that in Ln_(4)(L_(1)^(·+))_(4)(Ln=La^(Ⅲ)and Lu^(Ⅲ))constructed by diamagnetic Ln ions.This difference in radical stability is possibly due to the magnetic interactions between paramagnetic Ln^(Ⅲ)ions and L_(1)^(·+)ligands,as confirmed by electron paramagnetic resonance(EPR)in La_(4)(L)_(4)(L=L_(1)and L_(1)^(·+))and Tb_(4)(L)_(4)(L=L_(1)and L_(1)^(·+)),and magnetic susceptibility measurements in Tb·_(4)(L)_(4)(L=L_(1)and L_(1)^(·+)).Our study reveals the coordination of radical ligands with lanthanide ions can improve the radical stability,which is crucial for their applications.
基金supported by Senior Talent Fund of Jiangsu University(No.5501310021)China Postdoctoral Science Foundation(No.2023M741419)+1 种基金the Young Elite Scientist Sponsorship Program by ZJAST(No.G301310002)Research Fund for International Scientists(No.22350710187).
文摘Lanthanide-sensitized upconverting nanoparticles(UCNPs)are widely studied because of their unusual optical characteristics,such as large antenna-generated anti-Stokes shifts,high photostability,and narrow emission bandwidths,which can be harnessed for a variety of applications including bioimaging,sensing,information security and high-level anticounterfeiting.The diverse requirements of these applications typically require precise control over upconversion luminescence(UCL).Recently,the concept of energy migration upconversion has emerged as an effective approach to modulate UCL for various lanthanide ions.Moreover,it provides valuable insights into the fundamental comprehension of energy transfer mechanisms on the nanoscale,thereby contributing to the design of efficient lanthanide-sensitized UCNPs and their practical applications.Here we present a comprehensive overview of the latest developments in energy migration upconversion in lanthanide-sensitized nanoparticles for photon upconversion tuning,encompassing design strategies,mechanistic investigations and applications.Additionally,some future prospects in the field of energy migration upconversion are also discussed.
基金Project supported by the Science and Technology Projects of Fujian Province(2022Y0041)。
文摘Volatile organic compounds(VOCs)are significant indoor and outdoor air pollutants.Thermocatalysis is one of the most common methods for their removal,capable of completely mineralizing VOCs.Nanomaterials derived by pyrolytic means,based on the high specific surface area and high tunability of metal-organic frameworks(MOFs),have received increasing attention in the field of efficient catalysis of VOCs.Lanthanide metal-organic frameworks(Ln-MOFs)have significant research value in thermocatalytic applications for VOCs by virtue of their flexible and rich coordination behaviors,Lewis acidity,excellent oxygen storage and discharge capabilities,unique electronic structure properties of lanthanide coordination metals.Herein,a comprehensive review of the recent advances in Ln-MOF-based catalysts for thermally catalyzed VOCs elaborates on the effects based on the structure,including pyrolysis strategy,metal substitution,surface modification,and composite doping.The review addresses the mechanistic issues of Ln-MOF-based catalysts in the thermocatalysis of VOCs and highlights their characteristic advantages as efficient catalysts for VOCs.Finally,this review also summarizes the key issues and challenges,provides perspectives and outlooks on the development and design of Ln-MOFbased catalysts.It serves as a reference for enhancing the performance and selecting appropriate LnMOF-based catalysts for treating VOCs.
基金Project supported by the National Natural Science Foundation of China(21661034)Reserve Talents Project for Youth and Middle-Aged Academic and Technical Leaders of Yunnan Province(202205AC160032)。
文摘Metal-organic frameworks(MOFs)usually exist in the state of powder or crystal.When they are exposed to hydrophilic solvents,their structure will change and become unstable.Therefore,it is a challenge to construct MOF materials with tunable mechanical properties.Herein,we report in-situ growth lanthanide metal-organic framework(LnMOF)in sodium alginate(SA)and polyvinyl alcohol(PVA)hydrogel matrix.The prepared composite hydrogel not only displays characteristic lanthanide narrow-band emission under ultraviolet light,but also demonstrates excellent mechanical properties.The addition of LnMOF significantly enhances the compressive strength of the hydrogel(from 0.75 to 7.32 MPa).Furthermore,the composite hydrogel shows highly selective recognition of glutaraldehyde and gaseous formaldehyde at room temperature.The detection limits(LOD)of SP-EuMOF for glutaraldehyde and formaldehyde are 0.27 and 0.22 ppm,respectively.Based on these results,the LnMOF composite hydrogel is deemed to have significant potential as a fluorescent sensor for both glutaraldehyde and formaldehyde detection.
基金Supported by the National Natural Sciene Foundation of China(21171119,11574408,81573822,21376008)the Beijing Natural Science Foundation(2172017,2172012)+2 种基金the Beijing Municipal Education Commission(KM201510028006)the Scientific Research Base Development Program of the Beijing Municipal Commission of Educationthe Key Laboratory of Functional Inorganic Material Chemistry(Heilongjiang University)。
文摘Two novel lanthanide-based coordination complexes,[LaL(Phen)(NO_(3))_(3)]n(1)and[Pr_(2)L_(2)(Phen)2(NO_(3))_(6)]n(2),were synthesized via a stoichiometric 1∶1∶1 reaction of lanthanide nitrates with tetraisopropyl 1,2-ethylenediphosphate(L)and 1,10-phenanthroline(Phen)in a mixed ethanol-acetonitrile solvent system at room temperature.Their structures were determined by single-crystal X-ray diffraction(SCXRD)and further confirmed by infrared spectroscopy and elemental analysis.Thermogravimetric analysis(TGA)was used to assess thermal stability.Complexes 1 and 2 are both composed of O atoms provided by L and nitrate ions,formed a 10-coordinate configuration with the central Ln^(3+)(Ln=La,Pr)ion.Complex 1 forms a one-dimensional infinite chain connected by bridging ligands and constructs a complex three-dimensional stacking structure through hydrogen bonding andπ…πweak interactions.Complex 2 is connected by ligand L to form a one-dimensional infinite chain and through weak forces such as hydrogen bonding and C-H…πbonds,a novel three-dimensional stacking structure is formed by transverse and longitudinal crossing.
基金Project supported by the Zhejiang Provincial Natural Science Foundation of China (LY24E020005)Industrial Key Projects of Jinhua City(2023-1-090)。
文摘Mixed-lanthanide(Ln) luminescent materials have important application values in ratiometric temperature sensing.Hydrogen-bonded organic frameworks(HOFs) offer a self-supporting network to conveniently tune multiple Ln^(3+)ions,but challenges still exist in material design.In this work,we selected two simple organic molecules as hydrogen-bonded building blocks,which are melamine(MA) and 2,5-pyridinedicarboxylic acid(PDC) owning the suitable energy to sensitize Tb^(3+)and Eu^(3+)ions.MA assists PDC molecules to support the network in a new HOF(MA-PDC),where the abundant carboxylic groups enable Ln^(3+)ions to combine with the HOF.Based on the effective energy transfer process,the emission of Tb^(3+)and Eu^(3+)from TbxEu1-x@MA-PDC(x=0.75,0.85,0.90) shows the obvious temperature dependence,which benefits ratiometric temperature detection.Taking Tb0.85Eu0.15@MA-PDC as an example,when temperature varies from 303 to 443 K,the intensity ratio exhibits distinct S-type response based on Mott-Seitz model.It also behaves good relative sensitivity(1.03%/K at 383 K),low temperature resolution(0.059 K) and large reproducibility(>96%).This work demonstrates that functionalization of a simple-component HOF with mixed Ln^(3+)ions is a fantastic strategy to develop novel ratiometric thermometers of both low cost and good performance.
基金the National Key Research and Development Program of China(No.2021YFB3501501)the National Natural Science Foundation of China(No.22276013)the Beijing Natural Science Foundation(No.2242009)for financial support,and thank Tianhe2-JK HPC for generous computer time.
文摘Scientists have devoted considerable effort overs several decades to reduce automobile exhaust emissions,and one practical and important strategy is the catalytic conversion of nitric oxide(NO)[1].Previous studies have shown that lanthanide(Ln)metals can catalytically reduce NO.Thus,the reactions of NO with Ln to form lanthanide-nitric oxide(LnNO)complexes have been designed and served as the simplest prototype molecules for studying NO chemisorption on metal surfaces[2].
基金Project support by the National Natural Science Foundation of China(21171046,21502039,21271060)the Natural Science Foundation of Hebei Province(No.B2016202147,B2016202149,B2017202048)+2 种基金Educational Committee of Hebei Province(LJRC021,QN2015172)Hebei Provincial College of Science and Technology Research Project(BJ2018054)Tianjin Natural Science Foundation(18JCYBJC17200)
文摘Interest in lanthanide complexes in the synthetic clays remains growing considerably during the last decades because of the attractive features of the individuals. Synthetic clays like Laponite~? and Aminoclay show great potentials in building up the luminescent hybrid materials due to their obvious advantages such as high purity, high dispersibility(or solubility) in water to yield translucent gels and clear aqueous solution. Additionally, their strong adsorption capacity for non-polar molecules or complexes is favorable to the formation of water-soluble and aqueous processable luminescent materials. This feature article summarizes the latest developments in the design and preparation of highly luminescent organicinorganic hybrid materials with excellent aqueous process ability based on lanthanide complexes intercalated synthetic clays.
基金Project supported through grants from the Swiss National Science Foundationthe WCU program from the National Science Foundation of Korea for grant R31-10035
文摘Present-day advanced technologies heavily rely on the exciting magnetic and spectroscopic properties of lanthanide ions. In particular, their ability to generate well-characterized and intense near-infrared (NIR) luminescence is exploited in any modern fiber-optic telecommunication network. In this feature article, we first summarize the whereabouts underlying the design of highly luminescent NIR molecular edifices and materials. We then focus on describing the main trends in three applications related to this spectral range: telecommunications, biosciences, and solar energy conversion. In telecommunications, efforts concentrate presently on getting easily processable polymer-based waveguide amplifiers. Upconversion nanophosphors emitting in the visible after NIR excitation are now ubiquitous in many bioanalyses while their application to bio-imaging is still in its early stages; however, highly sensitive NIR-NIR systems start to be at hand for both in vitro and in vivo imaging, as well as dual probes combining magnetic resonance and optical imaging. Finally, both silicon-based and dye-sensitized solar cells benefit from the downconversion and upconversion capabilities of lanthanide ions to harvest UV and NIR solar light and to boost the overall quantum efficiency of these next-generation devices.
文摘Calcium tungstate phosphors activated by the Ln3＋ ions （Ln-Pr, Nd, Tb, Yb） were synthesized by a traditional high-temperature solid-state method. The crystal structures and morphologies of the products were characterized by scanning electron microscopy （SEM）, X-ray powders diffraction （XRD） and infrared spectra （FT-1R）. The samples were fotmd to show luminescence properties （down-conversion, DC, at excitation wavelength 254 nm and up-conversion, UC, at excitation wavelength 980 nm）. CaWO4 doped with Tb3＋/yb3＋ showed green DC and UC luminescence characteristic of Tb（Ⅲ） ion in the range of 470-660 nm, cor- responding to the 5D4→7F6,5,4,3,2 electronic transition. CaWO4 doped with Pr3＋/Yb3＋ showed week blue, green and red （DC and UC） luminescence of Pr（Ⅲ） ion, in the wavelength region of 450-700 nm. Emission peaks were ascribed to the 3P1→3H4,5,6, 3P0→3H4,5,6, 3P1→3F2 and 3P0→3F2 transitions, respectively. CaWO4 doped with Nd3＋/yb3＋ phosphor emitted orange UC luminescence at 450-690 nm （2p3/2→4I15/2, 4G7/2→419/2,11/2,13/2） and strong near-infrared UC luminescence at 720-900 nm （4F7/2＋4S3/2→4419/2, 4F5/2＋2H3/2→419/2, 4F3/2→4I9/2） which is the characteristic of Nd（Ⅲ） ion.
基金support from the University of Kerala for the award of afellowship
文摘The complexes of rare earth elements with 1,2-diphenyl-4-butyl-3,5-Pyrazolidinedione （PBH, phenylbutazone） were synthesized and characterized by elemental analysis, molar conductance, IR, UV-Vis, EPR and magnetic moment measurements. Based on these studies the complexes were formulated as [Ln（PB）3（H2O）2].nH2O, where Ln=Eu（III）, Gd（III）, Tb（III）, Dy（III） and Er（III）. From IR spectra, it was found that PBH acted as a bidentate mono-ionic ligand coordinating through two carbonyl oxygen of the pyrazolidinedione ring. The thermal analysis of all the complexes was carried out at a heating rate of 10 oC/min. The kinetic aspects of the complexes were evaluated. The nega-tive entropy value of the complexes indicated a more ordered state for the activated complexes. The photoluminescence property of Tb（III） complex was investigated. It showed all the characteristic emission peaks of Tb^3＋ with a life time of 0.98914 ms.
基金Project supported by the National Natural Science Foundation of China(21161023,21661034)
文摘Photoluminescent hybrid materials containing carboxymethyl cellulose and lanthanide ions（Eu3＋, Tb3＋）were prepared by a facile method under ambient conditions. Lanthanide ions were covalently grafted to the cellulose framework through coordination with the carboxylic groups of the cellulose. Hybrid materials were fabricated as hydrogel and aerogel. As shown by SEM and pore parameters, aerogel materials which were obtained by supercritical CO2 drying show hierarchical porous structure. The photoluminescence spectrum of the hybrid materials shows the characteristic red emission of Eu3＋ ion and green emission of Tb3＋. Further luminescent investigations reveal that these hybrid materials can detect Fe3＋ with relative selectivity and high sensitivity, which suggests that the hybrid materials could be a promising luminescent probe for selectively sensing Fe3＋ ion.
基金Project supported by the Swiss National Science Foundation
文摘Trivalent lanthanide ions display fascinating optical properties. The discovery of the corresponding elements and their first industrial uses were intimately linked to their optical properties. This relationship has been kept alive until today when many high-technology applications of lanthanide-containing materials such as energy-saving lighting devices, displays, optical fibers and amplifiers, lasers, responsive luminescent stains for biomedical analyses and in cellulo sensing and imaging, heavily rely on the brilliant and pure-color emission of lanthanide ions. In this review we first outlined the basics of lanthanide luminescence with emphasis on f-f transitions, the sensitization mechanisms, and the assessment of the luminescence efficiency of lanthanide-containing emissive molecular edifices. Emphasis was then put on two fast developing aspects of lanthanide luminescence： materials for telecommunications and light emitting diodes, and biomedical imaging and sensing. Recent advances in NIR-emitting materials for plastic amplifiers and waveguides were described, together with the main solutions brought by researchers to minimize non-radiative deactivation of excited states. The demonstration in 1999 that erbium tris（8-hydroxyquinolinate） displayed a bright green emission suitable for organic light emitting diodes （OLEDs） was followed by realizing that in OLEDs, 25% of the excitation energy leads to singlet states and 75% to triplet states. Since lanthanide ions are good triplet quenchers, they now also play a key role in the development of these lighting devices. Luminescence analyses of biological molecules are among the most sensitive analytical techniques known. The long lifetime of the lanthanide excited states allows time-resolved spectroscopy to be used, suppressing the sample autofluorescence and reaching very low detection limits. Not only visible lanthanide sensors are now ubiquitously provided in medical diagnosis and in cell imaging, but the feasibility of using NIR emission of ions such as YbⅢ is now being tested because of deeper penetration in biological tissues.
