Two-dimensional correlation spectroscopic studies on coordination between carbonyl group of butanone and metalions

Two dimensional asynchronous spectra were used to characterize coordination between carbonyl group of butanone and metal ions by using an approach proposed in our recent paper.Spectral variation of n-π~*transition band of carbonyl group is used to probe the coordination even if metal ions does not possess any characteristic peak in spectra.Experimental results indicate that Ca~(2+) and Al~(3+) show considerable ability to coordinate with the carbonyl group of butanone and bring about spectral variation of the n-π~*transition band,which is manifested by cross peaks in 2D asynchronous spectra.     

Growth and Spectroscopic Properties of Nd3＋：Sr3Gd2（BO3）4 Crystal

<正>This paper reports the growth,X-ray diffraction and spectroscopy of Nd~(3+):Sr_3Gd_2(BO_3)_4 crystal.A Nd~(3+):Sr_3Gd_2(BO_3)_4 crystal with dimensions ofφ20×45 mm~3 has been grown by the Czochralski method.Nd~(3+):Sr_3Gd_2(BO_3)_4 crystal belongs to the orthorhombic system,space group Pnma(D_(2h))with a=0.7401,b=1.604 and c=0.8755 nm.The absorption and emission spectra of Nd~(3+):Sr_3Gd_2(BO_3)_4 were investigated.The absorption cross sectionσ_a is 3.11×10~(-20)cm~2 at 808 nm. The absorption transition at 808 nm has an FWHM of 14 nm.The luminescence lifetimeτ_f is 51.7 us.The emission cross sectionσ_e at 1064 nm wavelength is 1.09×10~(-19)cm~2.     

Ce3+,Tb3+,Eu3+共掺杂Sr2MgSi2O7体系的白色发光和能量传递机理

通过正交试验,采用高温固相法制备了Sr2-x-y-zMgSi2O7∶xCe3+,yTb3+,zEu3+系列样品.使用X射线衍射仪和荧光光谱仪表征了样品的物相和发光性质,并讨论了Ce3+-Tb3+-Eu3+共掺杂Sr2MgSi2O7体系中的能量传递过程.实验结果表明,在327 nm波长激发下,所合成荧光粉的发射峰主要位于387 nm(蓝紫)、542nm(绿)和611 nm(红)处;分别以387,542和611 nm为监控波长,所得激发光谱显示荧光粉在327 nm处有最好的激发.在327 nm光激发下,系列样品发光进入白光区.最优化的荧光粉为Sr1.91MgSi2O7∶0.01Ce3+,0.05Tb3+,0.03Eu3+,其色坐标为(0.337,0.313),是一种潜在的发光二极管(LED)用白色荧光粉.     

Spectroscopic studies on the interaction of cilostazole with iodine and 2,3-dichloro-5,6-dicyanobenzoquinone

Lanthanide sensitized luminescence and chemiluminescence (CL) are of great importance because of the unique spectral properties, such as long lifetime, large Stokes shifts, and narrow emission bands characteristic to lanthanide ions (Ln³⁺). With the fluoroquinolone (FQ) compounds including enoxacin (ENX), norfloxacin (NFLX), lomefloxacin (LMFX), fleroxacin (FLRX), ofloxacin (OFLX), rufloxacin (RFX), gatifloxacin (GFLX) and sparfloxacin (SPFX), the luminescence and CL properties of Tb³⁺–FQ and Eu³⁺–FQ complexes have been investigated in this contribution. Ce⁴⁺–SO₃²⁻ in acidic conditions was taken as the CL system and sensitized CL intensities of Tb³⁺–FQ and Eu³⁺–FQ complexes were determined by flow-injection analysis. The luminescence and CL spectra of Tb³⁺–FQ complexes show characteristic peaks of Tb³⁺ at 490 nm, 545 nm, 585 nm and 620 nm. Complexes of Tb³⁺–ENX, Tb³⁺–NFLX, Tb³⁺–LMFX and Tb³⁺–FLRX display relatively strong emission intensity compared with Tb³⁺–OFLX, Tb³⁺–RFX, Tb³⁺–GFLX and Tb³⁺–SPFX. Quite weak peaks with unique characters of Eu³⁺ at 590 nm and 617 nm appear in the luminescence and CL spectra of Eu³⁺–ENX, but no notable sensitized luminescence and CL of Eu³⁺ could be observed when Eu³⁺ is added into other FQ. The distinct differences on emission intensity of Tb³⁺–FQ and Eu³⁺–FQ might originate from the different energy gap between the triplet levels of FQ and the excited levels of the Ln³⁺. The different sensitized luminescence and CL signals among Tb³⁺–FQ complexes could be attributed to different optical properties and substituents of these FQ compounds. The detailed mechanism involved in the luminescence and CL properties of Tb³⁺–FQ and Eu³⁺–FQ complexes has been investigated by analyzing the luminescence and CL spectra, quantum yields, and theoretical calculation results.     

Specific heat functions for the orthorhombic Nd3+ in scheelite type of crystals

Nd3+ doped scheelite type of crystals have attracted extensive interests because of their applications in solid state lasers, as well as upconversion luminescence and magneto-optical and magnetic properties. Usually, these properties are closely related to the local structures and properties of the Nd3+ impurities in the hosts. Since information about electronic states and local structures of the impurity Nd3+ in the scheelite crystals would be helpful to the understanding of the properties of these materials, theoretical investigations on the specific heat functions and the local structures for these Nd3+ centers are of significance.     

BaLaB9O16中Ce3+敏化Dy3+发光的机理

在紫外光激发下,研究了BaLaB₉O₁₆中Dy³⁺、Ce³⁺的发光光谱、激发光谱、发光强度及荧光寿命随着组成变化的规律性.结果表明;De³⁺对Dy³⁺的发光有相当强的敏化作用,Ce³⁺→Dy³⁺的能量传递效率可高达93%,能量传递的机理为电偶极-偶极相互作用的共振传递.根据349nm激发下Dy³⁺发光强度与浓度的关系,证明了Dy³⁺发光的自身浓度猝灭机理也为电偶极-偶极相互作用.     

白色荧光粉NaGd（MoO4）2:Dy3+,Eu3+的水热合成及发光性能

采用谷氨酸辅助水热法合成了八面体形NaGd(MoO4)2:Dy3+,Eu3+白色荧光粉.X射线衍射结果表明,合成的样品为四方晶系的NaGd(MoO4)2纯相.扫描电子显微镜照片显示所制备的粒子为八面体形,各边长约为2μm.荧光光谱结果表明,在NaGd(MoO4)2:4%Dy3+,yEu3+(y=0,0.5%,0.6%,0.7%,0.8%,0.9%,1.0%)样品中,随着Eu3+掺入量的增加,Dy3+的发射峰逐渐减弱,而Eu3+的发射峰逐渐增强,说明Dy3+-Eu3+之间存在能量传递.通过色坐标图可知,当Eu3+掺杂量y=0.9%时,荧光粉的色坐标(0.338,0.281)与标准的白光色坐标(0.33,0.33)接近,表明NaGd(MoO4)2:4%Dy3+,0.9%Eu3+是很好的近紫外光激发下的白色荧光粉.     

GdAlO_3:Er~(3+),Yb~(3+)荧光粉的制备与上转换发光性能

采用共沉淀、溶胶-凝胶和固相反应法制备了GdAlO3:Er3+,Yb3+荧光粉.借助X射线衍射、扫描电子显微镜、傅里叶变换红外光谱、N2-吸附、吸收光谱和荧光光谱等手段研究了不同方法制备的GdAlO3:Er3+,Yb3+荧光粉结构、形貌、表面基团和光吸收及上转换发光性能.结果表明:用共沉淀法比固相反应法和溶胶-凝胶法可以在更温和的条件下制得纯相GdAlO3:Er3+,Yb3+荧光粉,用共沉淀法和溶胶-凝胶法制备的GdAlO3:Er3+,Yb3+荧光粉颗粒都在纳米尺寸,溶胶-凝胶法制得的样品存在相对严重的颗粒团聚现象,而用固相反应法制备的荧光粉为微米级颗粒.GdAlO3:Er3+,Yb3+荧光粉在980 nm激发的上转换发射光谱包含波长为524和546 nm的绿光与659 nm的红光,且三种方法制备的样品绿光发射强度都显著高于红光.不同方法制备的荧光粉上转换发光强度和红光/绿光强度比相差较大,共沉淀法制备的样品上转换发光强度要显著高于固相法以及溶胶-凝胶法制备的样品,而溶胶-凝胶法制备的样品发光中红光/绿光相对强度比最高.红外光谱显示,不同方法制备的GdAlO3:Er3+,Yb3+荧光粉表面OH-、CO32-及CO2官能团含量不同,溶胶-凝胶法制备的样品要明显高些.基于红外光谱、不同Er3+和Yb3+离子掺杂浓度及不同激光功率上转换发光的结果,对Er3+和Yb3+之间的能量传递过程及不同方法制备荧光粉的上转换发光性能进行了讨论.     

铽(Ⅲ)与PvdA作用的光谱研究

Pyoverdine A(PvdA)是荧光假单胞菌分泌的一种水溶性较高的黄绿色荧光铁载体。在50mmol·L^-1Tris-HCl,pH8.0条件下,使用紫外-可见吸收差光谱、荧光光谱研究了铽(Ⅲ)与荧光铁载体PvdA的结合。结果表明铽(Ⅲ)可与PvdA结合形成1：1的配合物,条件结合常数为(4.44±0.82)×10¹⁴mol^-1·L。在生理条件下,PvdA可竞争伴清蛋白N-,C-端结合的铽(Ⅲ)形成Tb-PvdA配合物;Tb-PvdA与荧光假单胞菌细胞表面受体FpvA结合形成Tb-PvdA-FpvA复合物。     

Charge-transfer interaction of some pyridinium salts with hen egg-white lysozyme

The charge-transfer interaction of pyridinium salts with lysozyme and L-tryptophan has been investigated by visible absorption, circular dichroism and fluorescence spectroscopy. Four quaternized and substituted pyridinium salts were used as electron acceptors. L-tryptophan was used as a model compound of electron donor for the purpose of the comparison with lysozyme. The binding constants obtained from absorption and circular dichroism spectra were 2.0–13 M^–1 and the sequence of the magnitude was found as EPCl(1-ethylpyridinium chloride) < MPCl(1-methylpyridinium chloride) < MNCl(1-methylnicotinamide chloride) < MNMCl(1-methyl-3-carbomethoxypyridinium chloride), which could be explained by the electron affinity of the pyridinium salt. The fluorescence spectra of lysozyme and L-tryptophan in the absence and presence of pyridinium salts were interpreted by Stern-Volmer plot. The static constants thus determined were in agreement with the binding constants obtained by other methods.     

ZnO-B2O3∶Tb3+长余辉玻璃的发光性质

通过还原方法制备了Tb³⁺离子掺杂的硼酸锌玻璃，并观察到在254 nm紫外光激发后有明亮的绿色长余辉发光现象，余辉时间达6 h。通过激发与发射光谱、余辉光谱、余辉衰减曲线、热释光谱、热释光释出速率衰减曲线等得到的信息，研究了Tb³⁺离子掺杂的硼酸锌玻璃的发光性质。     

表柔比星-镁体系与DNA相互作用初步研究

表柔比星是临床上用于治疗快速增殖肿瘤的药物。本文应用紫外、荧光、圆二色、黏度、凝胶电泳等方法研究了表柔比星-Mg2+体系与DNA的作用。结果发现:在pH=7.4时,表柔比星可与Mg2+形成稳定体系。加入DNA后表柔比星-Mg2+体系的紫外吸收明显降低;Scatchard图表明表柔比星-Mg2+体系对溴化乙锭(EB)与DNA的结合为竞争性抑制;同时此体系可使DNA-EB体系荧光偏振度增大;使DNA的热变性温度(Tm)上升;黏度增大;凝胶电泳表明表柔比星-Mg2+体系对pBR322DNA有非常好的切割活性;圆二色谱法表明随着表柔比星-Mg2+体系的加入,DNA碱基间作用能迅速减弱,二级结构发生了显著的变化。综上所述:表柔比星-Mg2+体系与DNA之间为嵌插作用;且表柔比星-Mg2+体系具有更好的切割活性。这些结果,可为合理改善药效和设计新药提供依据。     

Anti-Stokes Yb3+ emission--valuable structure information in spectra of rare earth compounds measured with FT-Raman spectrometers

Raman spectroscopy is a powerful and simple method which proved to be very useful in studies of solids. The most widely used Raman spectrometers are FT-Raman instruments with YAG:Nd(3+) laser as an excitation source. However, in the case of samples containing rare earth elements, the quality of FT-Raman spectra is often low due to strong fluorescence effects. We show that, in such cases, anti-Stokes part of the Raman spectra often contains strong, well resolved bands identified as multiphonon-assisted emission bands of Yb(3+) present as an impurity. We show on several examples that analysis of these bands may provide useful structure information, similar to that obtained by "Eu structure probe" method in optical spectroscopy. The Yb(3+) emission can be also measured using standard luminescence detection systems. However, the application of FT-Raman system allows one to obtain good quality spectra in a much cheaper, easier and faster way (in times as short as a few seconds). Moreover, high-sensitivity of FT-Raman spectrometers allows to detect even very small amounts of Yb(3+) impurity.     

Optical spectroscopy of europium 3,5-dinitrosalicylates—Intense red luminophores

It was found, that alkali metal-europium dinitrosalicylates of composition M₃Eu(3,5-NO₂-Sal)₃·nH₂O (M = Li, Na, K, Cs) are intense red luminophores with wide excitation band. Using methods of optical spectroscopy we studied the influence of nitrogroups and alkali metal counterions on Eu³⁺ luminescence efficiency and on processes of excitation energy transfer to Eu³⁺ ion in compounds synthesized. The Eu³⁺ luminescence and Eu³⁺ luminescence excitation spectra, as well as vibrational IR and Raman spectra were investigated. Details of the structure of compounds were discussed. The network of hydrogen bonds in lanthanide dinitrosalicylates is weakening at introduction of large alkali metal ions in compounds and at the increase of the temperature. As a consequence, the long-wavelength shift of the intraligand charge transfer (ILCT) band in Eu³⁺ excitation spectra arises at inclusion of Cs⁺ cations instead of Li⁺ in the crystal lattice of europium dinitrosalicylates and at heating of these compounds. To obtain the energy of the lowest excited triplet state the phosphorescence spectra of alkali metal-gadolinium compounds M₃Gd(3,5-NO₂-Sal)₃·nH₂O, of alkali metal dinitrosalicylate and salicylate salts were measured with time delay. Change of the energies of ligand electronic states and ligand–metal charge transfer state (LM CTS) can give a two-three orders of magnitude enhancement of the Eu³⁺ luminescence efficiency in dinitrosalicylates in comparison with salicylates and ten-fold enhancement at the substitution of Li⁺ and Na⁺ for Cs⁺ in dinitrosalicylates.     

YAG∶Ce体系中稀土离子掺杂对Ce3+的光谱性能的影响

采用高温固相法合成了一系列的(Y0.95Ln0.01Ce0.04)3Al5O12(简称YAG∶Ce,Ln), 系统地研究了此体系中的Ln3+对Ce3+的发光强度的影响. 结果表明, 在YAG∶Ce的体系中, La3+, Gd3+, Lu3+等光学透明离子的少量掺杂对Ce3+的发光强度的影响不大; 掺入少量的Pr3+, Sm3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+等稀土离子, 由于它们的能级与Ce3+的能级有交叠, 使它们之间存在着竞争吸收或能量转移, 对Ce3+的发光有较明显的变化, 其中, Pr3+和Sm3+的掺入使其在红光区有发射峰, 可以增加YAG∶Ce的红色成分以提高显色性; Nd3+, Eu3+和Yb3+对Ce3+的发光有严重的猝灭作用.     

Enoxacin-Tb complex as an environmentally friendly fluorescence probe for DNA and its application

The fluorescence intensity of the enoxacin (ENX)-Tb³⁺ complex enhanced by DNA was studied. On the basis of this study, an environmentally friendly fluorescence probe of enoxacin-Tb³⁺ for the determination of single-stranded and double-stranded DNA was developed. Under the optimal conditions, the enhanced fluorescence intensity was in proportion to the concentration of DNA in the range of 2.0 × 10⁻⁸ to 2.0 × 10⁻⁶ g mL⁻¹ for hsDNA, 1.0 × 10⁻⁸ to 1.0 × 10⁻⁶ g mL⁻¹ for ctDNA and 5.0 × 10⁻⁹ to 1.0 × 10⁻⁶ g mL⁻¹ for thermally denatured ctDNA. The detection limits (S/N = 3) were 5.0, 9.0 and 3.0 ng mL⁻¹, respectively. The interaction modes between ENX-Tb³⁺ and DNA and the mechanism of the fluorescence enhancement were also discussed in details. The experimental results from UV absorption spectra, fluorescence spectra and the competing combination tests between the ENX-Tb³⁺ complex and EB probe indicated that the possible interaction modes between enoxacin-Tb³⁺ complex and DNA had at least two different binding modes: the electrostatic binding and the intercalation binding. Additionally, this fluorescence probe was used to study the interaction between heavy metals and DNA.     

Photophysical and Photochemical Properties of Ru(bpy)3 2+ in Si-Ti Mixed Oxides Xerogels Prepared by the Sol-Gel Process

The luminescence spectra and lifetime of tris(2,2-bipyridine)ruthenium(II), Ru(bpy)₃ ²⁺, were studied in sol-gel reaction systems of tetramethoxysilane (TMOS) and titanium(IV) isopropoxide (TTIP) with HCl. Luminescence lifetime in the TMOS system increased as the sol-gel reaction proceeded, because diffusion-controlled luminescence quenching such as oxygen and collisional quenching with solvent molecules were suppressed in the rigid matrices. On the other hand, luminescence lifetime in the TTIP system decreased during the sol-gel reaction. The decrease in lifetime was ascribed to electron transfer from photoexcited Ru(bpy)₃ ²⁺ to the conduction band of the TiO₂ xerogels. Extended X-ray absorption fine structure (EXAFS) measurements were done to associate lifetime in the Si-Ti xerogels with the structures of Ti⁴⁺ sites in the xerogels.     

White-light-emitting long-lasting phosphorescence in Dy-doped SrSiO3

We report on a luminescent phenomenon in Dy³⁺-doped SrSiO₃ long-lasting phosphor. After irradiation by a 254-nm UV lamp for 5 min, the Dy³⁺-doped SrSiO₃ phosphor emits white light-emitting long-lasting phosphorescence for more than 1 h even after the irradiation source has been removed. Photoluminescence, long-lasting phosphorescence and thermoluminescence (TL) spectra are used to explain this phenomenon. Photoluminescence spectra reveal that the white light-emitting long-lasting phosphorescence originated from the two mixtures of Dy³⁺ characteristic luminescence, the 480-nm blue emission (⁴F_9/2→⁶H_15/2) and the 572-nm yellow emission (⁴F_9/2→⁶H_13/2). TL spectra shows that the introduction of Dy³⁺ ions into the SrSiO₃ host produces a highly dense trapping level at 377 K (0.59 eV), which is responsible for the long-lasting phosphorescence at room temperature. A possible mechanism of the long-lasting phosphorescence based on the experimental results is proposed. It is considered that the long-lasting phosphorescence is due to persistent energy transfer from the electron traps to the Dy³⁺ ions, which creates the persistent luminescence of Dy³⁺ to produce the white light-emitting long-lasting phosphorescence.     

苯乙烯三嗪衍生物的合成及在重金属离子识别中的应用

合成了2,4-二(2-噻吩乙烯基)-6-(4'-N,N-二甲氨基苯乙烯基)-1,3,5-均三嗪(2)并鉴定了其结构。在乙腈-水混合介质中,化合物2在355和416nm处呈现双吸收峰,加入Cu²⁺,Hg²⁺ 和Fe³⁺ 后,均在520nm附近形成新的吸收峰。化合物2与Cu²⁺、Hg²⁺ 和Fe³⁺ 均形成1:1型配合物,其结合常数分别为1.9×10⁵L·mol^-1,6.6×10³L·mol^-1,2.7×10³L·mol^-1。对照化合物4与金属离子的光谱响应与化合物2相似,仅吸收峰的位置不同。因此,可认为化合物2和4中三嗪环中的N和噻吩环中的S与Cu²⁺、Hg²⁺ 和Fe³⁺ 共同配位形成了稳定的金属配合物。     

Ca9Y(PO4)7:Ce3+,Tb3+纳米荧光粉的制备及发光性能

采用水热法制备出Ca₉Y（PO₄）₇：Ce³⁺,Tb³⁺纳米荧光粉,通过XRD、SEM和荧光光谱等对样品进行了分析,研究在Ca₉Y（PO₄）₇基质中引入Ce³⁺,Tb³⁺离子对发光性能的影响规律。研究发现因Tb³⁺离子自身能量交叉驰豫的存在,使得单掺Tb³⁺时,通过调节Tb³⁺离子的浓度可以实现对发光颜色的控制。同时研究了Ce³⁺-Tb³⁺之间的能量传递为电多极相互作用的偶极-四极机制,Ce³⁺-Tb³⁺之间最大的能量传递效率为55.6%。Ca₉Y（PO₄）₇：Ce³⁺,Tb³⁺的发光颜色可以通过激活离子之间的能量传递和共发射得到可控调节。SEM分析表明荧光粉颗粒尺寸在100 nm左右,分散性好。