含吡唑啉酮三脚架结构的化合物及其稀土配合物的合成、表征及荧光性能

合成了一种含吡唑啉酮的三脚架结构化合物 1,1,1 三 { 1′ [2′ 氧杂 5′ 氧代 5′ ( 1″ 苯基 3″ 甲基吡唑啉酮 4″ 基 )戊基 ] }丙烷 (H3 L)及其 7个稀土配合物。通过元素分析、摩尔电导、质谱、红外光谱、核磁共振谱、荧光光谱等对H3 L及其稀土配合物的组成及性质进行了表征。分析结果表明 :H3 L的分子式为C45H50 N6O9,配合物的组成比为REL·0 5H2 O (RE =La ,Sm ,Eu ,Gd ,Tb ,Dy ,Yb) ;该三脚架形配体分别以醚氧、烯醇氧及吡唑酮环上的羰基氧与稀土离子进行配位 ,形成内配型配合物。荧光光谱分析表明SmL·0 5H2 O ,EuL·0 5H2 O ,TbL·0 5H2 O ,DyL·0 5H2 O配合物具有三价稀土离子的特征线状荧光 ,其中TbL·0 5H2 O的荧光强度最强 ,表明T(配体 )→5D4(Tb)能级更为匹配 ,从而进行分子内能量有效传递 ;由EuL·0 5H2 O的荧光光谱图形推测 ,Eu3 +离子在该配合物中处于非对称中心     

Laser-induced fluorescence microscopic system using an optical parametric oscillator for tunable detection in microchip analysis

A laser-induced fluorescence microscopic system based on optical parametric oscillation has been constructed as a tunable detector for microchip analysis. The detection limit of sulforhodamine B (Ex. 520 nm, Em. 570 nm) was 0.2 mol, which was approximately eight orders of magnitude better than with a conventional fluorophotometer. The system was applied to the determination of fluorescence-labeled DNA (Ex. 494 nm, Em. 519 nm) in a microchannel and the detection limit reached a single molecule. These results showed the feasibility of this system as a highly sensitive and tunable fluorescence detector for microchip analysis.     

Singlet exciplexes between a thioxanthone derivative and substituted aromatic quenchers: role of the resonance integral

Fluorescence quenching of a thioxanthone derivative by methyl- and methoxy-substituted benzenes (MeB and MeOB, respectively) is performed in solvents of different polarity. Emissive exciplexes are observed even in polar solvents and provide kinetic and spectroscopic data over a large scale of solvent polarity. These data were subsequently analyzed by use of a new theoretical model that leads to a thermodynamic relationship between exciplex and electron-transfer driving forces Delta G(exc) and Delta G(et), respectively. The remarkable agreement found between this model and both kinetic and spectroscopic data supports its validity. Moreover, the difference observed between MeB and MeOB compounds in quenching efficiency is analyzed by this model and provides the main parameters governing exciplex features, especially the resonance integral between locally excited and charge-transfer states.     

Cu2+与烟草多酚氧化酶相互作用研究

本文通过酶活性测定，荧光光谱和紫外光谱研究了外加Cu²⁺与烟草多酚氧化酶(简称PPO)的相互作用。结果表明，微量铜的加入能增加酶的活性，[Cu²⁺]/[PPO]为0.20左右时酶活性最大，[Cu²⁺]/[PPO]为0.91时，Cu²⁺开始表现出对PPO活性的抑制;Cu²⁺对PPO内源荧光的猝灭机制属于形成络合物所引起的静态猝灭，猝灭常数K_sv为8.0375×10³L·mol^-1;Cu²⁺的加入使PPO蛋白质分子构象发生变化，α-螺旋含量增加，多肽链及Trp和Tyr残基的芳杂环进一步向分子内收缩，疏水基团之间的疏水作用增强。     

Counterion Exchange Selectivity in Detergent–Polymer Aggregates

In aqueous solution, the interaction between sodium dodecyl sulfate (SDS) and poly(ethylene glycol) (PEG) results in the formation of small aggregates or clusters of SDS attached to the PEG polymer chain. Selectivity coefficients for exchange of two monovalent (N-methyl-4-cyanopyridinium cation and Tl⁺) and two divalent (methylviologen cation and Cu²⁺) counterions at the surface of SDS–PEG clusters, determined employing photophysical techniques, are similar, but not identical, to those for exchange at the surface of SDS micelles in the absence of PEG. The principal factor affecting ion exchange selectivity in SDS–PEG clusters does not appear to be aggregate size or surface charge density but rather the presence of poly(oxyethylene) subunits at the aggregate surface.     

硅钨杂多酸与牛血红蛋白相互作用的研究

多金属氧酸盐作为抗艾滋病病毒、抗流感病毒和抗肿瘤的药物,引起了人们对多金属氧酸与蛋白质之间相互作用的极大关注。蛋白质空间结构的任何变化引起的构象变化都意味着蛋白质分子的活性改变,因此,蛋白质与内源性化合物及许多药物分子之间相互作用的研究一直受到人们关注[1￣3]。血红蛋白是动物及人体内执行输氧任务的蛋白质,是生命机体进行各种生理活动的主要承担者。血红蛋白分子中每条α链和β链含有的色氨酸(Trp)残基分别为α-14Trp、β-15Trp、β-37Trp。Alpert[4]等认为位于疏水腔内的β-37Trp是血红蛋白内源荧光的主要来源,同时β…     

Molecule-Responsive Fluorescent Sensors of α-Helix Peptides Bearing α-Cyclodextrin, Pyrene and Nitrobenzene Units in Their Side Chains

-Helix peptides bearing one unit of -cyclodextrin (-CD), one unit of pyrene and one unit of nitrobenzene (NB) in their side chains have been designed and synthesized as novel molecule-responsive devices.In both the CD-peptides, -PR17 and -PL17, the NB unit is separated from the CD unit by two turns of the helix. Two reference peptides (PL17, and -P17,) have also been synthesized. The circular dichroism studies in the peptide absorption region (200–250 nm)of -PR17 and -PL17 suggestthat the CD-peptides form stable-helixstructures (83–77%), which was destabilized by accommodating guest molecules (e.g., n-pentanol) into the CD cavity. It suggests that formation of intramolecular host–guest(CD–NB) complex stabilized thehelical structure and exogenous guest molecule excluded the appending NB moiety from inside to outside of the CD cavity, thereby causing destabilization of the helical structure and increasing the random coil content. The ICD spectra of the peptides in the pyrene and nitrobenzene absorption region (250–40 nm) suggest that NB forms inclusion complex with CD. The fluorescence studies revealed that the fluorescence of the pyrene unit is quenched by the NB unit in -PR17 and -PL17. The fluorescence intensity increases with increasing guest concentration for the CD-peptides.This guest-responsiveenhancement in the fluorescence intensity can be explained in terms of increased distance between the pyrene and NB moieties, which is caused by exclusion of the NB moiety from the CD cavity by guest accommodation. Using the guest-responsive fluorescence quenching properties of the CD-peptides, we have obtained binding constants for various short chain alkanols. -PL17 has higher binding affinity to the guest molecules than its isomer, -PR17, indicating that the location of functional groups on the peptide scaffold is important in molecule detection.     

PhenNO—TTA—乳化剂OP荧光光度法测定微量铕

研究了Ｅｕ（Ⅲ）－ＰｈｅｎＮＯ－ＴＴＡ－乳化剂ＯＰ体系的荧光性质及其用于微量铕的测定。该体系具有良好的分析特性，最低检测限可达７．０×１０＾－１４ｍｏｌ／Ｌ．     

Fluorescence lifetimes of diphenylhexatriene-containing probes reflect local probe concentrations: Application to the measurement of membrane fusion

An important process in the life of a cell is fusion between cellular membranes. This is the process by which two cellular compartments surrounded by different membranes join to become a single compartment surrounded by a single membrane, without significant loss of compartment contents. To demonstrate fusion, the cell biophysicist must demonstrate all three critical aspects of the process: (1) mixing of membrane components, (2) mixing of compartment contents; and (3) retention of compartment contents. Most commonly, accomplishing this involves the use of fluorescence probes. The general theme to the methods described involves some form of concentration-dependent quenching. An unique method developed in our laboratory utilizes the concentration dependence of the fluorescence lifetime of a phosphatidylcholine containing carboxyethyl diphenylhexatriene at position 2 and palmitic acid at position 1 of glycerol (DPHpPC). The fluorescence lifetime of this molecule and that of its parent fluorophore diphenylhexatriene (DPH) shorten dramatically as their two-dimensional concentrations in a membrane increase. This lifetime quenching can be described by dimer formation that reduces the symmetry of the DPH excited state. This phenomenon allows one to use the fluorescence lifetime to gain insight into the local concentration of probe in microscopic regions of a membrane. One application of this is in distinguishing lipid transfer between the outer leaflets of two contacting membrane bilayers from fusion between these membranes that leads to mixing of lipids in both the inner and outer leaflets of the membrane bilayers. This allows a single measurement to demonstrate fusion between membrane pairs.Abbreviations PEG poly(ethylene glycol) - Na₂EDTA ethyiene-diamine-tetraacedic acid, disodium salt - LUV large, unilamellar vesicles made by rapid extrusion technique - DPH 1,6-diphenyl-trans-1,3,5-hexatriene - DPHpPC 1-palmitoyl-2-[[[2-[4- (phenyl-trans-1,3,5-hexatrienyl)phenyl]ethyl]oxy]carbonyl]-3-sn-phosphatidylcholine - DPPC 1,2-dipalmitoyl-3-sn-phosphatidylcholine - PA palmitic acid - NBD-PE N-(7-nitro-2,1,3-benzoxadiazol-4-yl)-PE - Rh-PE N-(lissamine Rhodamine B sulfoyl)-PE - R₁₈ octadecyl Rhodamine B chloride - ANTS 1-aminonaphthalene-3,6,8-trisulfonic acid - DPX N,N-p-xylylene-bis(pyradinium bromide)