Interactions between pyridinium and Nd3+

In this paper,2D asynchronous spectra generated by using the DAOSD approach was utilized to probe interactions between Nd~(3+) and pyridinium dissolved in aqueous solution.A series of cross peaks in the resultant 2D asynchronous spectrum confirms the occurrence of intermolecular interaction between Nd~(3+)and pyridinium.However,no coordination occurs between Nd~(3+) and pyridinium.Interaction between πelectron from aromatic system and/electron from lanthanide ions account for the appearance of cross peaks in 2D asynchronous spectra.Because of the interaction,the emission spectrum of pyridinium exhibits a significant change when neodymium perchlorate was introduced into the system.     

A rhodamine derivative for Hg2+-selective colorimetric and fluorescent sensing and its application to in vivo imaging

A rhodamine-based sensor has been developed for the detection of mercuric ions. The colorimetric and fluorescence responses, allowing naked-eye detections, are based on Hg~(2+)-induced opening of the rhodamine spirocycle. Among all the testes ions, only Hg~(2+)generated a significant fluorescence enhancement of up to 300-fold, with a bright yellow–green emission. This sensor was a low toxic compound, and was successfully applied in the in vivo imaging of Hg~(2+)in Spill 2 cells and C. elegans. This approach provides a sensitive and accurate method for the estimation of Hg~(2+)in environmental, tobacco and biological applications.     

Effect of Alkali Metal Ions(Li~+, Na~+ and K~+) on the Luminescent Properties of ZnTiO_3:Eu~(3+) Phosphors

A series of red emitting ZnTiO_3 phosphors co-doped with Eu~(3+) and alkali metal ions(Li~+, Na~+ and K~+) was prepared by sol-gel method. The crystal structure of the phosphors was investigated by using X-ray diffraction(XRD) and transmission electron microscopy(TEM) after annealing at 700 ℃. The results show that the crystal structure belongs to the hexagonal phase of ZnTiO_3 with space group R-3:R. The influence of site occupancy of different alkali metal ions on the emission of ZnTiO_3:Eu~(3+) phosphors was investigated in detail. The emission intensity was significantly enhanced by introducing alkali metal ions. In contrast to Eu~(3+) singly doped ZnTiO_3, the red emission intensities of ZnTiO_3:Eu~(3+) with 4 mol% alkali metal ions(Li~+, Na~+, K~+) were enhanced by about 2.1, 1.7 and 1.4 times, respectively. In addition, the Commission Internationale Ed I'eclairage(CIE) chromaticity coordinates of ZnTiO_3:Eu~(3+), Li~+(0.672, 0.328) are quite similar to the National Television Standard Committee(NTSC) standard values for the red(0.670, 0.380).     

PREPARATION AND PROPERTY OF POLYMERIC PENDANT Ru(bpy)_3~(2+) COMPLEXES

Polymeric pendant Ru(bpy)_3~(2+) complexes were prepared from homopolymer and copolymers of 4-methyl-4'-vinyl-2,2'-bipyridine (Vbpy). Vbpy was prepared from 4-methylpyridine. The comonomers were styrene (St), acrylic acid (AA), N-vinylpyrrolidone (Pyr), 4-vinylpyridine (Vpy), methyl methacrylate (MMA), 2-hydroxyethyl methacrylate (HEMA), acrylonitrile (AN) and N-ethyl-4-vinylpyridium bromide (EQ-Vpy). The fraction of the pendant Ru(bpy)_3~(2+) repeating unit in the polymeric complex was 0.022 to 0.052. Absorption maximum, molar extinction coefficient, emission maximum and relative emission intensity of the polymeric complexes were studied.     

Transitional Area of Ce~(4+) to Ce~(3+) in Sm_xCa_yCe_(1-x-y)O_(2-δ) with Various Doping and Oxygen Vacancy Concentrations: A GGA + U Study

In this work,we perform DFT+U periodic calculations to study geometrical and electronic structures and oxygen vacancy formation energies of Sm_xCa_yCe_(1-x-y)O_(2-δ)systems(x=0.0312,0.0625,0.125 and 0.250;y=0.0312,0.0625,0.125 and 0.250;δ=0.0312,0.0625,0.125,0.250 and 0.50)with different oxygen vacancy and doping concentrations.The calculated results show that the V_1-Sm~(3+)-V_2 structures where there is a position relationship of the face diagonal between V_1 and V_2 both nearest to Sm~(3+)have the lowest energy configurations.The study on electronic structures of the Sm_xCa_yCe_(1-x-y)O_(2-δ)systems finds that excess electrons arise from oxygen vacancies and are localized on f-level traps of their neighbor Ce,and Ca~(2+)and Sm~(3+)co-doping effectively restrains the reduction of Ce~(4+).In order to avoid the existence of Ce~(3+),x and y must be both larger than 0.0625 asδ=0.125 orδmust be smaller than 0.125 as x=y=0.0625.The Ce~(3+)/Ce~(4+)change ratio k has an obvious monotonous increase with increasing the vacancy oxygen concentration.The introduction of Sm~(3+)decreases k.In addition,the doped Sm~(3+)can restrain the reduction of Ce~(4+)when the V_1-Sm~(3+)-V_2 structure with a face diagonal position relationship in lower reduced atmosphere exists.It need be pointed out that the Sm_(0.25)Ce_(0.75)O_(1.5) system should be thought of as a Sm-doped Ce_2O_3 one.     

Preparation and Spectroscopic Properties of Tris(2,2′-bipyridine)ruthenium(Ⅱ) Loaded in Siliceous Mesoporous MCM-41

[Ru(bpy)3]2+/MCM-41 composite material obtained by loading tris(2,2′-bipyridine)ruthenium(Ⅱ)([Ru(bpy)3]2+) in siliceous mesoporous MCM-41 was characterized by X-ray powder diffraction, UV-Vis absorption and emission spectroscopies. The absorption spectrum of [Ru(bpy)3]2+/MCM-41 is similar to that of [Ru(bpy)3]2+ aqueous solution, whereas its emission spectrum exhibits hypsochromic shift compared to the solution spectrum. On the other hand, the peak position of the emission spectrum of [Ru(bpy)3]2+/MCM-41 shifts towards longer wavelength when the loading amount increases.     

Up/downconversion luminescence rare-earth ion-doped Y2O3 1D nanocrystals

Multicolor luminescent rare-earth ion-doped Y2O3 nanocrystals(NCs) were prepared by a solvethermal method.The as-synthesized NCs yielded nanosheets,nanowires(NWs) and nanorods(NRs) with the increase of alkali(NaOH) in oleic acid system.Moreover,Y2O3 nanowires with controllable size have also been obtained.After sintering,the PL intensity of Y2O3:Ln 3+ nanocrystals increased with the changed morphology of the precursor,that is,Y(OH) 3 nanocrystals.Both downconversion(red emission for Y2O3:Eu 3+ and green emission for Y2O3:Tb 3+) and upconversion(red emission for Y2O3:Yb/Er 3+) luminescence of the as-prepared nanocrystals have been demonstrated in this work.We also found that the PL intensity of Y2O3:Ln 3+ NCs dispersed in polar solvent was stronger than that in nonpolar solvent.Their up/downconversion fluorescence and controllable morphology might promise further fundamental research and biochemistry such as nanoscale optoelectronics,nanolasers,and ultrasensitive multicolor biolables.     

氧化铝对稀土有机配合物掺杂溶胶凝胶玻璃结构及发光性能的影响

Both silica glass materials singly doped with rare earth organic complex and co-doped with Al^3 were prepared by in situ sol-gel method respectively. XRD and SEM measurements were performed to verify the non-crystalline structure of the glass. The excitation spectra, emission spectra and IR spectra were measured to analyze the influence of the glass contents on the structure of the glass and the energy level of the doped Eu(IH) ions. The effect of Al^3 on the photoluminescence properties of rare earth organic complex in silica glass was investigated. The IR spectra indicated that the in situ synthesized europium complex molecule was confined to the micropores of the host and the vibration of the ligands was frozen. When Al2O3 was doped into the silica host gel, the rare earth ions in the silica network were wrapped up and dispersed by Al2O3, so the distribution of Eu(Ⅲ) complex in the host was morehomogeneous, and the luminescence intensity of ^5D0-^7F2 transition emission of the Eu^3 ions was improved. The results showed that an appropriate amount of Al^3 added to the gel glass improved the emission intensity of the complex in the silica glass, and when the content of Al2O3 reached 4 mol%, the maximum emission intensity could be obtained compared with that of other samples containing different Al2O3 contents.     

Effects of Doping and Oxygen Vacancy Concentrations on Oxygen Ion Migration in Sm_xCe_(1-x)O_(2-δ): a DFT + U Study

Influence of doping and oxygen vacancy concentrations on oxygen ion or oxygen vacancy(V) migration energies of Sm_xCe_(1-x)O_(2-δ)(x = 0.0625, 0.125, 0.25 and δ = 0.0625, 0.125) systems using a GGA+U method are studied. Calculated results show that advantage migration types change from V?O~(2-) to O~(2-) ?V as x and δ increase. For V?O~(2-) migrations of the Sm_(0.0625)Ce_(0.9375)O_(1.9375) and Sm_(0.125)Ce_(0.875)O_(1.9375) systems, electrostatic attractions between Sm~(3+) and V, defect associations between Ce~(3+) and V, and steric hindrances of Sm~(3+) affect the migration energies. For O~(2-) ?V migrations of the Sm+(0.125)Ce_(0.875)O_(1.875) and Sm_(0.25)Ce_(0.75)O_(1.875) systems, migration energies of O~(~(2-) ) are affected by electrostatic repulsions between Sm~(3+) and O~(2-) and defect associations between Ce~(3+) and V. Increases of the oxygen vacancy and Sm~(3+) doping concentrations benefit the oxygen ion and vacancy migrations, respectively.     

REPLACED SITE OF Eu~(2+) ION IN THE COMPLEX FLUORIDES WITH THE PEROVSKITE CRYSTAL STRUCTURE

The replaced site of Eu~(2+) ion is dependent on the electronegativitydifference of the cations in complex fluorides.In the mixed fluorideKMgF_3:Eu~(2+),Eu~(2+) ion occupies K~+ site,its emission spectrum is a sharpline and its valence-state is stable.     

Synthesis and luminescent properties of a silylated-terpyridine derivative and its metalated complexes in solutions and self-assembled monolayers

A silylated-terpyridine(Si TPy) derivative was newly synthesized and reacted with various transition metal ions in the solutions and self-assembled monolayers(SAMs).Composition and morphology of the SAMs were characterized by using absorption spectra,X-ray photoelectron spectra and atomic force microscope.The silylated-TPy compound gave off a luminescent emission at about 456 nm,which slightly shifted to 452 nm in the Zn2+-Si TPy and Fe2+-Si TPy metalated complexes.The absorbed energy can be further transferred to lanthanide ions(Tb3+and Eu3+) to give off the typical emissions of the lanthanide complexes together with an emission of the silylated-TPy at about 363 nm.     

Highly chemiluminescent magnetic mesoporous carbon composites Fe_3O_4@void@C with yolk-shell structure

In this work,highly chemiluminescent magnetic mesoporous carbon with yolk-shell structure was synthesized by encapsulating N-(4-aminobutyl)-N-ethylisoluminol(ABEI)and Co~(2+)into the magnetic mesoporous carbon composites(Co~(2+)-ABEI-Fe_3O_4@void@C).The synthetic Co~(2+)-ABEI-Fe_3O_4@void@C showed a good magnetic separation property,which could remove residual ABEI molecules and Co~(2+)in less than 3 min under an external magnet.Moreover,the synthetic Co~(2+)-ABEI-Fe_3O_4@void@C demonstrated good chemiluminescence(CL)property and good stability when interacted with alkaline H_2O_2solution.The CL intensity of such Co~(2+)-ABEI-Fe_3O_4@void@C was about 120 times higher than that of ABEI-Fe_3O_4@void@C.The Co~(2+)-ABEI-Fe_3O_4@void@C also exhibited good electrochemiluminescence(ECL)property in alkaline solution.The outstanding CL/ECL performance of the Co~(2+)-ABEI-Fe_3O_4@void@C was attributed to the Co~(2+)immobilized in the Co~(2+)-ABEI-Fe_3O_4@void@C,which catalyzed the decomposition of H_2O_2to generate O_2~(·-)and HO~·,expediting the CL/ECL reaction.The synthetic Co~(2+)-ABEI-Fe_3O_4@void@C may be of great application for the development of new methodologies in bioanalysis.     

Tris(2,2''''-bipyridyl)ruthenium(Ⅱ) electrochemiluminescence (ECL) enhanced by rutin on platinum electrode

Ru(bpy)_(3~(2 )) electrochemiluminescence (ECL) was applied to determination of rutin. ECL intensity of Ru(bpy)_(3~(2 ))could be enhanced in the presence of rutin in basic solution on platinum electrode. At pH 9.9, light emission intensity was found to be linear with rutin in the range of 1-50 mmol/L.     

EFFECT OF TRANSMEMBRANE Ca~(2+) GRADIENT ON CONFORMATION AND ENZYME ACTIVITY OF RECONSTITUTED ADENYLATE CYCLASE

Adenylate cyclase from bovine brain cortex was reconstituted into asolectin liposomes with (500-fold) or without transmembrane Ca~(2+) gradient. The enzyme activity of four types of proteoliposomes (the active center of enzyme exposing outside) was compared. The highest adenylate cyclase activity was observed in the vesicles with outside lower Ca~(2+)concentration (≈10~(-6) mol/L, similar to thephysiological condition). If the transmembrane Ca~(2+) gradient was in the inverse direction (i.e. outside higher Ca~(2+) concentration, 0.5 mmol/L), a lowest enzymatic activity would appear. The difference in enzymatic activity between the two types of proteoliposomes could be diminished following the addition of Ca~(2+) ionophore A23187. Proteoliposomes without transmembrane Ca~(2+) gradient exhibited intermediate activities.The conformation difference of adenylatecyclases in the above-mentioned proteoliposomes was also detected by measuring intrinsic fluorescence and fluorescence quenching with KI.     

Studies on the Coordination Polymer of Copper Electropolyurushiol

The coordination polymer of copper electropolyurushiol(EPU-Cu~(2+)) was obtained by the reaction of copper chloride with electropolyurushiol (EPU) in an isopropyl alcohol solution. The properties of EPU-Cu~(2+) were studied by means of ESR, FTIR, XPS, DMTA and TG-DTA. The results of AES show that the content of Cu~(2+) was 8.63％. The electric resistances of EPU-Cu~(2+) and EPU were determined to be 9, 37×10~(10) Ω and 7.90×10~(10) Ω respectively. It was also ascertained that in EPU-Cu~(2+) each Cu~(2+) is coordinated with two units hydroxyl in EPU, making the EPU-Cu~(2+) cross-link further. As a result, the title polymer exhibits an insolubility in most of organic solutions, a higher glass transition temperature and thermal resistance.     

CeCl_3和SmCl_3在氯化物熔盐中的电化学行为

利用计时电位法研究了Ce~(3+)在LiC1-KC1共晶熔体和Sm~(3+)在等摩尔KCl-NaCl熔体中固体阴极上的电化学反应。在LiCl-KCl熔体中,Ce~(3+)的电化学反应为:Ce~(3+)+3e→Ce°;在KCl-NaCl熔体中,Sm~(3+)为Sm_(3+)+e→Sm~(2+)。在600℃下Ce~(3+)的扩散系数Dc_e~(3+)=2.08·10~(-5)cm~2/s;Sm~(3+)的扩散系数与温度的关系式为:lgDs_m~(3+)=-2.802-250/T。实验结果表明,Ce~(3+)可完全放电变为Ce°;而Sm~(3+)在比其它稀土离子更正的析出电位下还原为Sm~(2+),在氧化还原条件下Sm~(2+)的电化学反应为;Sm~(3+)+eSm~(2+)。     

REBO3中Ce3+和Bi3+对Sm3+光致发光的影响

在紫外光(UV)激发下,系统地研究了REBO_3(RE=La,Gd,Y)中Sm~(3+),Ce~(3+)和Bi~(3+)的发射光谱、激发光谱及其发光强度与组成、结构的关系.结果表明:Ce~(3+)、Bi~(3+)均可敏化LaBO_3中Sm~(3+)的发光;而在GdBO_3和YBO_3中,只有Bi~(3+)能敏化Sm~(3+)的发光,Ce~(3+)猝灭Sm~(3+)的发光.本文还探讨了三种基质中Sm~(3+)发光浓度猝灭的机理.     

A selective and sensitive off–on probe for palladium and its application for living cell imaging

A new rhodamine B derivative T1 has been rationally synthesized and displayed selective Pd(Ⅱ)-amplified absorbance and fluorescence emission above 540 nm in methanol–water. Upon the addition of Pd(Ⅱ), the spirolactam ring was unfolded and a 1:1 metal-ligand complex formed, which can be used for ‘‘naked-eyes" detection. In addition, fluorescence imaging experiments of Pd~(2+) in HepG2 living cells showed its valuable application in biological systems.     

Synthesis of a di(2-picolyl)amino-b-diketone dual-functional ligand that can coordinate to europium(Ⅲ) for responding to copper(Ⅱ) and sulfide ions

Lanthanide complex-based luminescent probes/chemosensors have shown great utilities in various biological and environmental assays with time-resolved detection mode to eliminate background noises.In this work,by conjugating di(2-picolyl)amine(DPA)with a tetradentateβ-diketone 1,2-bis[4'-(1",1",1",2",2"-pentafluoro-3",5"-pentanedion-5"-yl)benzyl]-4-chlorosulfo-benzene(BPPBCB),a novel dual-functional ligand that can coordinate to Eu~(3+)for responding to Cu~(2+)and S~2 ions in aqueous media,DPA-BPPBCB,has been designed and synthesized.Theβ-diketone moiety of DPA-BPPBCB can form a strongly luminescent complex with Eu~(3+).Upon reaction with Cu~(2+),accompanied by the formation of heterobimetallic complex Cu~(2+)-DPA-BPPBCB-Eu~(3+),the Eu~(3+)luminescence was quenched.While in the presence of S~2,owing to the high affinity of S~2 to Cu~(2+),stable CuS was formed,which resulted in the release of Cu~(2+)from Cu~(2+)-DPA-BPPBCB-Eu~(3+),to restore the luminescence of the Eu~(3+)complex.This unique"on-off-on"luminescence response of the Eu3+complex enabled Cu~(2+)and S~2 ions in aqueous media to be detected with time-resolved luminescence detection mode.     

11-Mercaptoundecanoic acid functionalized gold nanoclusters as fluorescent probes for the sensitive detection of Cu2+ and Fe3+ ions

Metal ions are physiologically essential,but excessive metal ions may cause severe risk to plants and animals.Here,we prepared gold nanoclusters(Au NCs) protected by 11-mercaptoundecanoic acid(11-MUA),which have excellent fluorescence properties for the detection of metal ions.The results showed that the copper ions(Cu~(2+)) and iron ions(Fe~(3+)) in the solution have obvious quenching effect on the fluorescence intensity of Au NCs.The detection range of Fe~(3+) was 0.8–4.5 mmol/L(R~2= 0.992) and 4.5–11.0 mmol/L(R~2= 0.997).And Cu~(2+) has a lower linear range(0.1–1.0 mmol/L,R2= 0.993).When EDTA was added into the reaction system,it was observed that the quenching effect of Cu~(2+) and Fe~(3+)on Au NCs showed different phenomenon.Then,the effect of metal ions on the fluorescence of Au NCs was investigated.The selective detection of Cu~(2+) was achieved by EDTA masking of Fe~(3+).In addition,we realized the metal ions detection application of Au NCs in the serum