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1.
YF3:Tb, LaF3:Ce/Tb, and GdF3:Tb nanoparticles (NPs) were synthesized by the thermal co-precipitation technique at a lower temperature. X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA), Fourier transform infrared (FTIR), FT-Raman, UV/visible, and photoluminescence techniques were utilized to determine the phase purity, crystal phase, thermal stability, exterior behavior, optical properties, colloidal stability, and luminescent properties. The XRD results showed the different crystal phases in each nanoproduct. The TGA studies exhibited slight degradation at a lower temperature, which suggests surface water adsorption and organic moieties. The FTIR spectra revealed the existence of the IR bands related to hydroxyl and (C O) groups, suggesting the presence of organic moieties. The absorption spectra and optical bandgap energies were measured in aqueous media for the determination of the colloidal dispersibility in an aqueous solution. The excitation and emission spectra were analyzed, and all observed excitation and emission transitions were labeled. The emission spectra of the LnF3:Tb NPs exhibited distinctive features of the most dominant emission transition located at 543 (5D4 → 7F5) under the excitation at 368 nm. Among the presented LnF3 host matrices, YF3:Tb NPs demonstrated high crystallinity along with superior photoluminescence properties. These findings are highly useful in the conjugation of biomolecules for sensitive detection of biomolecules and optical bioimaging. 相似文献
2.
Dr. Sheng‐Liang Zhong Dr. Yang Lu Dr. Min‐Rui Gao Dr. Shu‐Juan Liu Jun Peng Le‐Cheng Zhang Prof. Dr. Shu‐Hong Yu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(17):5222-5231
A family of monodisperse YF3, YF3:Ce3+ and YF3:Ce3+/Ln3+ (Ln=Tb, Eu) mesocrystals with a morphology of a hollow spindle can be synthesized by a solvothermal process using yttrium nitrate and NH4F as precursors. The effects of reaction time, fluorine source, solvents, and reaction temperature on the synthesis of these mesocrystals have been studied in detail. The results demonstrate that the formation of a hollow spindle‐like YF3 can be ascribed to a nonclassical crystallization process by means of a particle‐based reaction route in ethanol. It has been shown that the fluorine sources selected have a remarkable effect on the morphologies and crystalline phases of the final products. Moreover, the luminescent properties of Ln3+‐doped and Ce3+/Ln3+‐co‐doped spindle‐like YF3 mesocrystals were also investigated. It turns out that Ce3+ is an efficient sensitizer for Ln3+ in the spindle‐like YF3 mesocrystals. Remarkable fluorescence enhancement was observed in Ce3+/Ln3+‐co‐doped YF3 mesocrystals. The mechanism of the energy transfer and electronic transition between Ce3+ and Ln3+ in the host material of YF3 mesocrystals was also explored. The cytotoxicity study revealed that these YF3‐based nanocrystals are biocompatible for applications, such as cellular imaging. 相似文献
3.
Lei Y Pang M Fan W Feng J Song S Dang S Zhang H 《Dalton transactions (Cambridge, England : 2003)》2011,40(1):142-145
Hydrophilic Ce, Tb doped BaYF(5) nanocrystals with uniform size were synthesized by a microwave-assisted route. The synthesized nanocrystals can be well dispersed in hydrophilic solutions (DMSO, DMF, EG, H(2)O). This synthesis procedure represents a less time consuming method, with high product yield and without using any assistant or/and template reagents, which may be expected to be a general method for rapid synthesis of other hydrophilic RE doped fluoride fluorescent nanocrystals. The Ce(3+), Tb(3+) codoped BaYF(5) nanocrystals show bright green fluorescence emission. The Ce(3+) acts as an effective energy transfer medium and the emission at the high (5)D(3) energy level of Tb is enhanced in this host material. 相似文献
4.
Shrikant A. Mohitkar 《Journal of solid state chemistry》2011,184(4):735-740
Nine new A2Mo4Sb2O18 (A=Ce, Pr, Eu, Tb, Ho, Er, Tm, Yb, Lu) compounds have been synthesized by solid-state reactions. They are isostructural with six reported analogues of yttrium and other lanthanides and the monoclinic unit cell parameters of all fifteen of them vary linearly with the size of A3+ ion. Single crystal X-ray structures of eight A2Mo4Sb2O18 (A=Ce, Pr, Eu, Gd, Tb, Ho, Er, Tm) compounds have been determined. Neat A2Mo4Sb2O18 (A=Pr, Sm, Eu, Tb, Dy, Ho, Er, Tm) compounds exhibit characteristic rare earth metal photoluminescence. 相似文献
5.
Systematic Investigation of Reaction‐Time Dependence of Three Series of Copper–Lanthanide/Lanthanide Coordination Polymers: Syntheses,Structures, Photoluminescence,and Magnetism 下载免费PDF全文
Dr. Ju‐Wen Zhang Xiao‐Min Kan Bin‐Qiu Liu Guo‐Cheng Liu Dr. Ai‐Xiang Tian Prof. Xiu‐Li Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(45):16219-16228
Three series of copper–lanthanide/lanthanide coordination polymers (CPs) LnIIICuIICuI(bct)3(H2O)2 [Ln=La ( 1 ), Ce ( 2 ), Pr ( 3 ), Nd ( 4 ), Sm ( 5 ), Eu ( 6 ), Gd ( 7 ), Tb ( 8 ), Dy ( 9 ), Er ( 10 ), Yb ( 11 ), and Lu ( 12 ), H2bct=2,5‐bis(carboxymethylmercapto)‐1,3,4‐thiadiazole acid], LnIIICuI(bct)2 [Ln=Ce ( 2 a ), Pr ( 3 a ), Nd ( 4 a ), Sm ( 5 a ), Eu ( 6 a ), Gd ( 7 a ), Tb ( 8 a ), Dy ( 9 a ), Er ( 10 a ), Yb ( 11 a ), and Lu ( 12 a )], and LnIII2(bct)3(H2O)5 [Ln=La ( 1 b ), Ce ( 2 b ), Pr ( 3 b ), Nd ( 4 b ), Sm ( 5 b ), Eu ( 6 b ), Gd ( 7 b ), Tb ( 8 b ), and Dy ( 9 b )] have been successfully constructed under hydrothermal conditions by modulating the reaction time. Structural characterization has revealed that CPs 1 – 12 possess a unique one‐dimensional (1D) strip‐shaped structure containing two types of double‐helical chains and a double‐helical channel. CPs 2 a – 12 a show a three‐dimensional (3D) framework formed by CuI linking two types of homochiral layers with double‐helical channels. CPs 1 b – 9 b exhibit a 3D framework with single‐helical channels. CPs 6 b and 8 b display visible red and green luminescence of the EuIII and TbIII ions, respectively, sensitized by the bct ligand, and microsecond‐level lifetimes. CP 8 b shows a rare magnetic transition between short‐range ferromagnetic ordering at 110 K and long‐range ferromagnetic ordering below 10 K. CPs 9 a and 9 b display field‐induced single‐chain magnet (SCM) and/or single‐molecule magnet (SMM) behaviors, with Ueff values of 51.7 and 36.5 K, respectively. 相似文献
6.
《Polyhedron》1988,7(1):79-81
The air and moisture stable complexes [Ln{HB(C3N2H3)3}2{MeC(O)CHC(O)Me}] (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Yb, Lu, Y), have been prepared and characterized. The molecular structures of the compounds with Ln = Ce and Yb reveal that a substantial distortion of the coordination geometry found for Ce3+ is necessary to allow the ligand set to accommodate the smaller Yb3+ ion. 相似文献
7.
Zhong Wei Jiang Yang Chun Zou Ting Ting Zhao Shu Jun Zhen Yuan Fang Li Cheng Zhi Huang 《Angewandte Chemie (International ed. in English)》2020,59(8):3300-3306
Synthesizing 2D metal–organic frameworks (2D MOFs) in high yields and rational tailoring of the properties in a predictable manner for specific applications is extremely challenging. Now, a series of porphyrin‐based 2D lanthanide MOFs (Ln‐TCPP, Ln=Ce, Sm, Eu, Tb, Yb, TCPP=tetrakis(4‐carboxyphenyl) porphyrin) with different thickness were successfully prepared in a household microwave oven. The as‐prepared 2D Ln‐TCPP nanosheets showed thickness‐dependent photocatalytic performances towards photooxidation of 1,5‐dihydroxynaphthalene (1,5‐DHN) to synthesize juglone. Particularly, the Yb‐TCPP displayed outstanding photodynamic activity to generate O2? and 1O2. This work not only provides fundamental insights into structure designing and property tailoring of 2D MOFs nanosheets, but also pave a new way to improve the photocatalytic performance. 相似文献
8.
A Family of 12‐Azametallacrown‐4 Structural Motif with Heterometallic MnIII‐Ln‐MnIII‐Ln (Ln=Dy,Er, Yb,Tb, Y) Alternate Arrangement and Single‐Molecule Magnet Behavior 下载免费PDF全文
Dr. Hua Yang Dr. Fan Cao Prof. Dacheng Li Dr. Suyuan Zeng Prof. You Song Prof. Jianmin Dou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(41):14478-14485
Mixed 3d–4f 12‐azametallacrown‐4 complexes, [Mn2Ln2(OH)2(hppt)4(OAc)2(DMF)2] ? 2 DMF ? H2O [Ln=Dy ( 1 ), Er ( 2 ), Yb ( 3 ), Tb ( 4 ) and Y ( 5 ), H2hppt=3‐(2‐hydroxyphenyl)‐5‐(pyrazin‐2‐yl)‐1,2,4‐triazole)], were synthesized by reactions of H2hppt with Mn(OAc)2 ? 4 H2O and Ln(NO3)3 ? 6 H2O. This is the first 3d–4f azametallacrown family to incorporate Ln ions into the ring sets. These isostructural complexes exhibit alternating arrangements of two Mn and two Ln ions in the rings with each pair of metal centers bound by an N?N group and μ2‐O bridging. Magnetic measurements revealed dominant antiferromagnetic interactions between metal centers, and frequency‐dependent out‐of‐phase (${\chi {^\prime}{^\prime}_{\rm{M}} }$ ) signals below 4 K suggest slow relaxation of magnetization. 相似文献
9.
A novel crystalline coordination polymer containing Ce3+ and bis(4‐nitrophenyl) phosphate (L), CeL3, was synthesized and its unique transmetalation selectivities toward Yb3+ and Lu3+ in the lanthanide series were evaluated. The relatively large difference in transmetalation selectivity between the neighboring Tm3+ and Yb3+ species is noteworthy because the reactivities of heavy lanthanides are generally considerably similar. The structural strain of the polymeric framework is likely responsible for this unusual trend. Powder X‐ray diffraction analysis indicated that, in the cases of only Yb3+ and Lu3+, large differences in their ionic sizes compared to that of Ce3+ in the parent framework may induce a structural strain after solid solution formation, while cleavage of the relatively weak Ce?O bond allows the formation of new Yb?O and Lu?O bonds with the incoming Yb3+ and Lu3+, respectively. Structural phase transitions likely caused by the heterogeneous nucleation of the Yb‐ (or Lu‐) type phase were also observed. 相似文献
10.
Template‐Free Synthesis and Mechanistic Study of Porous Three‐Dimensional Hierarchical Uranium‐Containing and Uranium Oxide Microspheres 下载免费PDF全文
Dr. Lin Wang Dr. Ran Zhao Dr. Cong‐zhi Wang Dr. Li‐yong Yuan Dr. Zhan‐jun Gu Dr. Cheng‐liang Xiao Dr. Shu‐ao Wang Dr. Xin‐wei Wang Prof. Yu‐liang Zhao Prof. Zhi‐fang Chai Dr. Wei‐qun Shi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(39):12655-12662
A novel type of uranium‐containing microspheres with an urchin‐like hierarchical nano/microstructure has been successfully synthesized by a facile template‐free hydrothermal method with uranyl nitrate hexahydrate, urea, and glycerol as the uranium source, precipitating agent, and shape‐controlling agent, respectively. The as‐synthesized microspheres were usually a few micrometers in size and porous inside, and their shells were composed of nanoscale rod‐shaped crystals. The growth mechanism of the hydrothermal reaction was studied, revealing that temperature, ratios of reactants, solution pH, and reaction time were all critical for the growth. The mechanism study also revealed that an intermediate compound of 3 UO3?NH3?5 H2O was first formed and then gradually converted into the final hydrothermal product. These uranium‐containing microspheres were excellent precursors to synthesize porous uranium oxide microspheres. With a suitable calcination temperature, very uniform microspheres of uranium oxides (UO2+x, U3O8, and UO3) were successfully synthesized. 相似文献
11.
The cerium‐containing MCM‐41 (Ce‐MCM‐41) has been synthesized by direct hydrothermal method. The low‐angle XRD patterns revealed the typical five major peaks of MCM‐41 type hexagonal structures. The interplanar spacing d100 = 38.4 Å was obtained that can be indexed on a hexagonal unit cell parameter with ao = 44.3 Å which was larger than that of pure siliceous MCM‐41 (Si‐MCM‐41). Transmission electron micrograph shows the regular hexagonal array of uniform channel characteristics of MCM‐41. The BET surface area of Ce‐MCM‐41 was 840 m2/g, which is much reduced as compared to that of Si‐MCM‐41, with the pore size of 26.9 Å and mesopore volume of 0.78 cm3/g were measured by nitrogen adsorption‐desorption isotherm at 77 K. Along with the results, the synthesized Ce‐MCM‐41 exhibited a well‐ordered MCM‐41‐type mesoporous structure with the incorporation of cerium. Using Ce‐MCM‐41 as a support, the Rh (0.5 wt%) catalyst exhibited very high activity for the NO/CO reactions. 相似文献
12.
M. Paula C. Campello Dr. Sara Lacerda Dr. Isabel C. Santos Dr. Giovannia A. Pereira Dr. Carlos F. G. C. Geraldes Prof. Dr. Jan Kotek Dr. Petr Hermann Dr. Jakub Vaněk Přemysl Lubal Vojtěch Kubíček Dr. Éva Tóth Isabel Santos Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(28):8446-8465
Complexes of 4,10‐bis(phosphonomethyl)‐1,4,7,10‐tetraazacyclododecane‐1,7‐diacetic acid (trans‐H6do2a2p, H6 L ) with transition metal and lanthanide(III) ions were investigated. The stability constant values of the divalent and trivalent metal‐ion complexes are between the corresponding values of H4dota and H8dotp complexes, as a consequence of the ligand basicity. The solid‐state structures of the ligand and of nine lanthanide(III) complexes were determined by X‐ray diffraction. All the complexes are present as twisted‐square‐antiprismatic isomers and their structures can be divided into two series. The first one involves nona‐coordinated complexes of the large lanthanide(III) ions (Ce, Nd, Sm) with a coordinated water molecule. In the series of Sm, Eu, Tb, Dy, Er, Yb, the complexes are octa‐coordinated only by the ligand donor atoms and their coordination cages are more irregular. The formation kinetics and the acid‐assisted dissociation of several LnIII–H6 L complexes were investigated at different temperatures and compared with analogous data for complexes of other dota‐like ligands. The [Ce( L )(H2O)]3? complex is the most kinetically inert among complexes of the investigated lanthanide(III) ions (Ce, Eu, Gd, Yb). Among mixed phosphonate–acetate dota analogues, kinetic inertness of the cerium(III) complexes is increased with a higher number of phosphonate arms in the ligand, whereas the opposite is true for europium(III) complexes. According to the 1H NMR spectroscopic pseudo‐contact shifts for the Ce–Eu and Tb–Yb series, the solution structures of the complexes reflect the structures of the [Ce(H L )(H2O)]2? and [Yb(H L )]2? anions, respectively, found in the solid state. However, these solution NMR spectroscopic studies showed that there is no unambiguous relation between 31P/1H lanthanide‐induced shift (LIS) values and coordination of water in the complexes; the values rather express a relative position of the central ions between the N4 and O4 planes. 相似文献
13.
Hyungwoo Kim Min Chul Cha Hyun Woo Park Ji Young Chang 《Journal of polymer science. Part A, Polymer chemistry》2013,51(24):5291-5297
We synthesized a Yb(III)‐incorporated microporous polymer (Yb‐ADA) and studied its gas adsorption property and catalytic activity. The adamantane‐based porous polymer (ADA) was obtained from an ethynyl‐functionalized adamantane derivative and 2,5‐dibromoterephthalic acid through Sonogashira–Hagihara cross‐coupling. ADA had two carboxyl groups which were used for Yb(III) coordination under basic conditions. The Brunauer‐Emmett‐Teller (BET) surface area of ADA was 970 m2 g?1. As Yb(III) ions were incorporated into ADA, the surface area of the polymer (Yb‐ADA) was reduced to 885 m2 g?1. However, Yb‐ADA exhibited a significantly enhanced CO2 adsorption capacity despite the reduction of surface area. The CO2 uptakes of ADA and Yb‐ADA were 1.56 and 2.36 mmol g?1 at 298 K, respectively. The H2 uptake of ADA also increased after coordination with Yb(III) from 1.15 to 1.40 wt % at 77 K. Yb‐ADA showed high catalytic activity in the acetalization of 4‐bromobenzaldehyde and furfural with trimethyl orthoformate and could be reused after recovery without severe loss of activity. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 5291–5297 相似文献
14.
Gaël Zucchi Dr. Olivier Maury Dr. Pierre Thuéry Dr. Frédéric Gumy Jean‐Claude G. Bünzli Prof. Dr. Michel Ephritikhine Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(38):9686-9696
Treatment of Ln(NO3)3?nH2O with 1 or 2 equiv 2,2′‐bipyrimidine (BPM) in dry THF readily afforded the monometallic complexes [Ln(NO3)3(bpm)2] (Ln=Eu, Gd, Dy, Tm) or [Ln(NO3)3(bpm)2]?THF (Ln=Eu, Tb, Er, Yb) after recrystallization from MeOH or THF, respectively. Reactions with nitrate salts of the larger lanthanide ions (Ln=Ce, Nd, Sm) yielded one of two distinct monometallic complexes, depending on the recrystallization solvent: [Ln(NO3)3(bpm)2]?THF (Ln=Nd, Sm) from THF, or [Ln(NO3)3(bpm)(MeOH)2]?MeOH (Ln=Ce, Nd, Sm) from MeOH. Treatment of UO2(NO3)2?6H2O with 1 equiv BPM in THF afforded the monoadduct [UO2(NO3)2(bpm)] after recrystallization from MeOH. The complexes were characterized by their crystal structure. Solid‐state luminescence measurements on these monometallic complexes showed that BPM is an efficient sensitizer of the luminescence of both the lanthanide and the uranyl ions emitting visible light, as well as of the YbIII ion emitting in the near‐IR. For Tb, Dy, Eu, and Yb complexes, energy transfer was quite efficient, resulting in quantum yields of 80.0, 5.1, 70.0, and 0.8 %, respectively. All these complexes in the solid state were stable in air. 相似文献
15.
P. Solokha PhD student S. De Negri A. Saccone V. Pavlyuk J.‐C. Tedenac 《无机化学与普通化学杂志》2007,633(3):482-489
The RENiZn (RE = La, Tb), RE2Ni2Zn (RE = La, Ce, Tb) and La3Ni3Zn ternary compounds were synthesized by two methods: by heating in a resistance furnace evacuated quartz ampoules containing Al2O3‐crucibles with element pieces and by induction melting in sealed Ta crucibles with subsequent annealing at 400 °C. Scanning electron microscopy (SEM) coupled with energy dispersive X‐ray spectroscopy (EDXS) was used for examining microstructure and phase composition of some of the alloys. The crystal structures for all the investigated phases were solved or confirmed on single crystal data by applying the direct methods refined by a standard least square procedure: LaNiZn – str. type ZrNiAl, hexagonal, , hP9, a = 0.7285(1), c = 0.3938(1) nm, wR2 = 0.0534, 257 F2 values, 14 variables; a = 0.7044(1), c = 0.3782(1) nm, wR2 = 0.0447, 236 F2 values, 14 variables for TbNiZn; La2Ni2Zn – str. type Pr2Ni2Al, orthorhombic, Immm, oI10, a = 0.4381(1), b = 0.5459(1) c = 0.8605(2) nm, wR2 = 0.0824, 223 F2 values, 13 variables; a = 0.4365(1), b = 0.5430(1) c = 0.8279(2) nm, wR2 = 0.0635, 209 F2 values, 13 variables for Ce2Ni2Zn; a = 0.4209(1), b = 0.5366(1) c = 0.8165 (1) nm, wR2 = 0.0757, 200 F2 values, 13 variables for Tb2Ni2Zn; La3Ni3Zn – str. type Y3Co3Ga, orthorhombic, Cmcm, oS28, a = 0.4276(1), b = 1.0310(2) c = 1.3636(3) nm, wR2 = 0.0859, 579 F2 values, 26 variables. The structural peculiarities of these compounds and their relations are discussed. 相似文献
16.
beta-NaYF4:Ln3+ (Ln = Eu, Tb, Yb/Er, and Yb/Tm) hexagonal microprisms with remarkably uniform morphology and size have been synthesized via a facile hydrothermal route. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and photoluminescence (PL) spectra as well as kinetic decays were used to characterize the samples. It is found that sodium citrate as a shape modifier introduced into the reaction system plays a critical role in the shape evolution of the final products. Furthermore, the shape and size of the products can be further manipulated by adjusting the molar ratio of citrate/RE3+ (RE represents the total amount of Y3+ and the doped rare earth elements such as Eu3+, Tb3+, Yb3+/Er3+, or Yb3+/Tm3+). Under the excitation of 397 nm ultraviolet light, NaYF4:xEu3+ (x = 1.5, 5%) shows the emission lines of Eu3+ corresponding to 5D0-3 --> 7FJ (J = 0-4) transitions from 400 to 700 nm (whole visible spectral region) with different intensity, resulting in yellow and red down-conversion (DC) light emissions, respectively. When doped with 5% Tb3+ ions, the strong DC fluorescence corresponding to 5D4 --> 7FJ (J = 6, 5, 4, 3) transitions with 5D4 --> 7F5 (green emission at 544 nm) being the most prominent group that has been observed. In addition, under 980 nm laser excitation, the Yb3+/Er3+- and Yb3+/Tm3+-codoped beta-NaYF4 samples exhibit bright green and whitish blue up-conversion (UC) luminescence, respectively. The luminescence mechanisms for the doped lanthanide ions were thoroughly analyzed. 相似文献
17.
Fan Zhang Jing Li Dr. Jiong Shan Lei Xu Prof. Dr. Dongyuan Zhao Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(41):11010-11019
High‐quality rare‐earth fluorides, α‐NaMF4 (M=Dy, Ho, Er, Tm, Y, Yb, and Lu) nanocrystals and β‐NaMF4 (M=Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Y, Yb, and Lu) nanoarrays, have been synthesized by using oleic acid as a stabilizing agent through a facile hydrothermal method at 130–230 °C. The phase, shape, and size of the products are varied by careful control of synthetic conditions, including hydrothermal temperature and time, and the amounts of reactants and solvents. Tuning the hydrothermal temperature, time, and the amount of NaOH can cause the transformation from the cubic α‐NaMF4 to hexagonal phase β‐NaMF4. Upon adjustment of the amount of NaOH, NaF, M3+, and ethanol, the morphologies for the β‐NaMF4 nanoarrays can range from tube, rod, wire, and zigzagged rod, to flower‐patterned disk. Simultaneously, the size of the rare‐earth fluoride crystals is variable from 5 nm to several micrometers. A combination of “diffusion‐controlled growth” and the “organic–inorganic interface effect” is proposed to understand the formation of the nanocrystals. An ideal “1D growth” of rare‐earth fluorides is preferred at high temperatures and high ethanol contents, from which the tube‐ and rodlike nanoarrays with high aspect ratio are obtained. In contrast, the disklike β‐NaMF4 nanoarrays with low aspect ratios are produced by decreasing the ethanol content or prolonging the reaction time, an effect probably caused by “1D/2D ripening”. Multicolor up‐conversion fluorescence is also successfully realized in the Yb3+/Er3+ (green, red) and Yb3+/Tm3+ (blue) co‐doped α‐NaYF4 nanocrystals and β‐NaYF4 nanoarrays by excitation in the NIR region (980 nm). 相似文献
18.
M. G. Abd El-Wahed S. M. El-Megharbel M. Y. El-Sayed Y. M. Zahran M. S. Refat M. A. Al-Omar A. M. Naglah 《Russian Journal of General Chemistry》2016,86(2):391-399
The complexation between the lanthanide metal ions Ce(III), Gd(III), Nd(III), Tb(III), and Er(III) and gliclazide produced 1 : 1 molar ratio metal: gliclazide (Glz) complexes coordinated in a monodentate fashion via the OH group and having the general formulas [M(Glz)Cl3(H2O)]·xH2O (M = Ce, Gd, Nd and x = 1, 3, 4, respectively) and [M(Glz)(H2O)4]Cl3·yH2O (M = Tb, Er and y = 1, 2, respectively). The structure of the synthesized lanthanide gliclazide complexes was assigned by IR, 1HNMR, and UV-Vis spectroscopy. Thermal analysis and kinetic and thermodynamic parameters gave evidence for the thermal stability of the Glz complexes. The latter showed a significant antimicrobial effect against some bacteria and fungi. 相似文献
19.
Philipp R. Matthes Jörn Nitsch Ana Kuzmanoski Prof. Claus Feldmann Dr. Andreas Steffen Prof. Todd B. Marder Prof. Klaus Müller‐Buschbaum 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(51):17369-17378
A series of 12 dinuclear complexes [Ln2Cl6(μ‐4,4′‐bipy)(py)6], Ln=Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, ( 1 – 12 , respectively) was synthesized by an anhydrous solvothermal reaction in pyridine. The complexes contain a 4,4′‐bipyridine bridge and exhibit a coordination sphere closely related to luminescent lanthanide MOFs based on LnCl3 and 4,4‐bipyridine. The dinuclear complexes therefore function as a molecular model system to provide a better understanding of the luminescence mechanisms in the Ln‐N‐MOFs ${\hbox{}{{\hfill 2\atop \hfill \infty }}}$ [Ln2Cl6(4,4′‐bipy)3] ? 2(4,4′‐bipy). Accordingly, the luminescence properties of the complexes with Ln=Y, Sm, Eu, Gd, Tb, Dy, ( 1 , 4 – 8 ) were determined, showing an antenna effect through a ligand–metal energy transfer. The highest efficiency of luminescence is observed for the terbium‐based compound 7 displaying a high quantum yield (QY of 86 %). Excitation with UV light reveals typical emission colors of lanthanide‐dependent intra 4f–4f‐transition emissions in the visible range (TbIII: green, EuIII: red, SmIII: salmon red, DyIII: yellow). For the GdIII‐ and YIII‐containing compounds 6 and 1 , blue emission based on triplet phosphorescence is observed. Furthermore, ligand‐to‐metal charge‐transfer (LMCT) states, based on the interaction of Cl? with EuIII, were observed for the EuIII compound 5 including energy‐transfer processes to the EuIII ion. Altogether, the model complexes give further insights into the luminescence of the related MOFs, for example, rationalization of Ln‐independent quantum yields in the related MOFs. 相似文献
20.
Three Isostructural 4‐Sulfophthalate‐Based Lanthanide Complexes: Syntheses,Crystal Structures,and Luminescent Properties 下载免费PDF全文
Three lanthanide complexes with the ligand 4‐sulfophthalate (sp3–), [Ln(H2O)2(sp)]n [Ln = Dy ( 1 ), Tb ( 2 ), and Er ( 3 )], were solvo‐/hydrothermally synthesized by changing the rare earth cations, and were characterized structurally and photophysically. Complexes 1 – 3 are isostructural, exhibiting a two‐dimensional layered structure with centrosymmetric dinuclear subunits infinitely extended by 4‐connected sp3– connectors. Photoluminescence spectra of 1 – 3 demonstrate that anionic sp3– ligand can serve as a functionalized chromophore to sensitize the luminescent emission of the lanthanide ion, suggesting that the sp3–‐involved lanthanide complexes can be used as novel optical materials. 相似文献