罗丹明B衍生物的合成及其对Cu2+,Hg2+的识别研究

以罗丹明B-酰肼和2-羟基-3-喹啉醛缩合反应得到新型罗丹明B衍生物L,其结构经1H NMR,MS及元素分析表征.通过紫外光谱法和荧光光谱法研究了目标物L在CH3CN-H2O溶液中与金属离子的识别特性.结果表明:目标物L作为探针可选择性比色识别Cu2+和荧光识别Hg2+.随着Cu2+或Hg2+的滴加,探针L的内酰胺环结构发生开环,并形成L-Cu2+1∶1配合物或L-Hg2+1∶2配合物,识别过程均是可逆的.     

作为Be2+磷光探针的含9-冠-3的铱配合物

以4′-(2-苯并噻唑基)苯并-9-冠-3(BTZ9C3)为主配体,用2,2′-联吡啶(bpy)及3-三氟甲基-5-(2′-吡啶基)-1,2-二唑(Hfppz)辅助配体分别合成了离子型铱配合物[Ir(BTZ9C3)2(bpy)]PF6(1)和中性铱配合物[Ir(BTZ9C3)2(fppz)](2)。配合物的结构通过核磁、高分辨质谱进行了表征,并测定了配合物1的单晶结构。对它们光物理性能的研究表明,2种配合物掺杂在PMMA中的发光为黄绿光发射,配合物1的发光波长为535 nm,配合物2的发光波长为541 nm,发光量子效率分别为10.8%,45.0%,发光寿命分别为3.01和2.58μs,为典型的磷光发射。通过循环伏安法测得配合物1和2的HOMO能级分别为-5.60和-5.35 eV。2种配合物对Be2+都有发光增强的选择性识别效果,化学计量比为1∶2,最低检测限低至6.0μmol·L-1。抗干扰能力方面,离子型配合物1的抗干扰能力较好,而中性配合物2受Al3+的干扰较大。     

多吡啶钴(Ⅲ)配合物与Zn2+形成的新型“关-开”荧光探针

近十几年来,对小分子过渡金属配合物与大分子DNA键合与识别机理的研究一直是国际上生物无机化学领域十分活跃的研究课题[1￣3],已发展了一系列具有特定功能的配合物,如DNA结构探针和DNA荧光探针等。与其他类型的金属配合物相比,八面体过渡金属多吡啶配合物具有丰富的光化学和光物理信息,当这些配合物与DNA相互作用时,由于结构匹配或微环境的差异,配合物的光谱特征会出现不同程度的改变,从而达到对DNA的检测。传统的DNA荧光探针有[Ru(bpy)2dppz]2 和[Ru(phen)2dppz]2 (bpy=2,2′-联吡啶,phen=1,10-菲咯啉,dppz=二吡啶[3,2-a∶2′,3′…     

新型罗丹明型荧光探针的合成及其对Cu(Ⅱ)的识别性能

罗丹明B-酰肼和8-羟基-7-喹啉醛经缩合反应合成了一个新型的荧光探针(L),其结构经1H NMR,MS和元素分析表征。考察了L对金属离子的识别性能,结果表明:在乙腈溶液[V(MeCN)∶V(H2O)=19∶1,pH7.0]中,L可高选择性的识别Cu(Ⅱ)。Cu(Ⅱ)能诱导L内酰胺结构开环并形成1∶2型的配合物L-Cu(Ⅱ),这一过程是可逆的。     

单取代罗丹明-硫杂杯[4]芳烃衍生物的合成及对Fe~(3+)离子的荧光探针性质研究

以1,3-交替-二羧基甲氧基硫杂杯[4]芳烃为原料,通过与罗丹明乙二胺衍生物的酰化反应得到罗丹明基团单取代的硫杂杯[4]芳烃衍生物。目标化合物结构经IR,NMR,MS及元素分析等技术表征。荧光及可见吸收光谱法研究表明化合物对Fe3+具有探针性质,在乙醇-水(1/1,V/V)Tris-HCl(pH=6.0)缓冲溶液中,对Fe3+呈现光关-开响应,并观察到显著的荧光增强和颜色变红现象。测定了Fe3+-配合物的组成、稳定常数及荧光量子产率。     

罗丹明型荧光探针的合成及对Hg2+的识别

本文以罗丹明B-酰肼和2-氯-3-喹啉醛经缩合反应得到新型的罗丹明B衍生物3,其结构经1H NMR,MS,元素分析表征.通过荧光光谱法研究了目标物3在CH3CN-H2O溶液中与金属离子的识别特性.结果表明:目标物3可作为荧光探针选择性识别Hg2+,识别过程是不可逆的.     

联苯二甲酸构筑的镍配合物的合成、晶体结构及对罗丹明B的光催化性能

通过水热方法获得了2个镍配合物:[Ni(3,3′-dpdc)(dpp)]n(1),[Ni(2,2′-dpdc)(phen)(H2O)2]n(2)(3,3′-H2dpdc=3,3′-联苯二甲酸,2,2′-H2dpdc=2,2′-联苯二甲酸、phen=菲咯啉,dpp=1,3-二(4-吡啶基)丙烷),通过X射线单晶衍射的方法测定了其晶体结构。配合物1为二维网格型结构,中心金属离子为扭曲的[NiO4N2]八面体构型,3,3′-dpdc配体的2个羧基采取双齿螯合的配位模式与Ni髤离子配位形成Ni-(3,3′-dpdc)一维链结构,dpp配体采取单氮原子桥连的配位模式连接2个Ni髤离子形成Ni-dpp一维链,两种链相互贯穿形成二维网格型结构,二维网格结构之间通过氢键C15D-H15…O2、C21-H21A…O1形成三维超分子结构。配合物2为一维之字链结构,中心金属离子为扭曲的[NiO_4N_2]八面体构型,2,2′-dpdc的2个羧基均采取单齿桥连配位模式连接2个Ni髤离子形成一维之字型链结构,一维链之间通过O-H…O和C-H…π弱作用力连接形成三维超分子结构。探究了2种配合物对有机染料罗丹明B的光催化降解性能,结果表明配合物可以高效地降解罗丹明B。     

Cu2＋和铜锌超氧化物歧化酶作用的光谱学研究

利用邻苯三酚自氧化法监测在磷酸盐缓冲体系中Cu^2＋对猪肝铜锌超氧化物歧化酶(CuZnSOD)活力的影响, 认为Cu^2＋与猪肝CuZnSOD存在直接相互作用. 通过荧光光谱方法研究了这种相互作用, 内源荧光的猝灭实验表明Cu^2＋与CuZnSOD形成1∶1型稳定配合物; 荧光猝灭的动力学分析表明配合物形成过程由两个独立步骤完成: 第一步是双分子快速缔合过程, 形成了结合疏松的配合物, 第二步是单分子慢速过程, 即松散的配合物“异构化”成为结合紧密的配合物. FTIR和CD证实相互作用过程伴随了蛋白分子构象的变化.     

Cu2＋和铜锌超氧化物歧化酶作用的光谱学研究

利用邻苯三酚自氧化法监测在磷酸盐缓冲体系中Cu^2＋对猪肝铜锌超氧化物歧化酶(CuZnSOD)活力的影响, 认为Cu^2＋与猪肝CuZnSOD存在直接相互作用. 通过荧光光谱方法研究了这种相互作用, 内源荧光的猝灭实验表明Cu^2＋与CuZnSOD形成1∶1型稳定配合物; 荧光猝灭的动力学分析表明配合物形成过程由两个独立步骤完成: 第一步是双分子快速缔合过程, 形成了结合疏松的配合物, 第二步是单分子慢速过程, 即松散的配合物“异构化”成为结合紧密的配合物. FTIR和CD证实相互作用过程伴随了蛋白分子构象的变化.     

一种同时分辨识别Zn2+和F-离子的双功能探针

由8-甲酰基-7-羟基香豆素与碳酰肼经一步缩合反应可制得探针1。研究发现,探针1对Zn²⁺和F^-离子均呈现荧光增强和比率比色的高灵敏和高选择性响应,检出限低至10^-8 mol·L^-1。通过光谱、ITC、¹H NMR滴定及质谱分析,详细地研究了探针与离子形成的配合物性质。在不同的介质中,探针不仅同时表现出对金属阳离子Zn²⁺和对阴离子F^-的识别,而且吸收和发射波长均有显著的差异：1-Zn²⁺配合物的最大吸收波长为360 nm,而1-F^-配合物为400 nm;1-Zn²⁺配合物的荧光激发和发射波长分别为360和454 nm,而1-F^-配合物分别为400和475 nm。此外,探针1还能应用于活体PC3细胞中Zn²⁺的荧光成像。     

Recombination of KrD and XeD ions with electrons

Recombination rate coefficients of protonated and deuterated ions KrH⁺, KrD⁺, XeH⁺ and XeD⁺ were measured using Flowing Afterglow with Langmuir Probe (FALP). Helium at 1600 Pa and at temperature 250 K was used as a buffer gas in the experiments. Kr, Xe, H₂ and D₂ were introduced to a flow tube to form the desired ions. Because of small differences in proton affinities of Kr, D₂ and H₂ mixtures of ions, KrD⁺/D₃⁺ and KrH⁺/H₃⁺ are formed in the afterglow plasma, influencing the plasma decay. To obtain a recombination rate coefficient for a particular ion, the dependencies on partial pressures of gases used in the ion formation were measured. The obtained rate coefficients, α_KrD+(250 K) = (0.9 ± 0.3) × 10⁻⁸ cm³ s⁻¹ and α_XeD+(250 K) = (8 ± 2) × 10⁻⁸ cm³ s⁻¹ are compared with α_KrH+(250 K) = (2.0 ± 0.6) × 10⁻⁸ cm³ s⁻¹ and α_XeH+(250 K) = (8 ± 2) × 10⁻⁸ cm³ s⁻¹.     

CO LMR spectrum of14N16O and its analysis with spectra of14N17O and14N18O

LMR spectra for v=1←0 transitions of¹⁴N¹⁶O in X²II_{1/2, 3/2} states were observed at 5.6 μm and 5.4 μm of CO laser. Introducing the advanced isotopic molecular constant scaling function to Hund’s case (a) diatomic structure model, these spectra were analyzed and fitted together with all reliable previous spectral data of¹⁴N¹⁶O as well as¹⁴N¹⁷O and¹⁴N¹⁸O. A full set of precise molecular parameters and their vibrational dependencies have been determined with much higher precision (1–2 orders for most parameters). Many of them have been obtained for the first time. Using isotopic scaling function, the molecular constants of¹⁴N¹⁷O and¹⁴N¹⁸O were deduced.     

Coordinate Structures of PrIII, GdIII, TmIII, and YbIII Complexes with Nitrilotriacetic Acids

The crystal and molecular structures of the [Pr^III(nta)(H₂O)₂]·H₂O (nta = nitrilotriacetic acids), K₃[Gd^III(nta)₂(H₂O)]·6H₂O, and K₃[Yb^III(nta)₂]·5H₂O complexes have been determined by single-crystal X-ray structure analyses. In [Pr^III(nta)(H₂O)₂]·H₂O, the Pr^IIINO₈ part forms a nine-coordinate pseudo-monocapped square antiprismatic structure in which one N and three O atoms are from one nta ligand in the same molecule, three O atoms from another nta ligand in the neighboring molecule and two O atoms from two coordinate water molecules. In K₃[Gd^III(nta)₂(H₂O)]·6H₂O, the [Gd^III(nta)₂(H₂O)^3- complex anion has a nine-coordinate pseudo-monocapped square antiprismatic structure in which each nta acts as a tetradentate ligand with one N atom of the amino group and three O atoms of the carboxylic groups. In K₃[Yb^III(nta)₂]·5H₂O, each nta also acts as a tetradentate ligand with one N atom of amino group and three O atoms of the carboxylic groups, but the [Yb^III(nta)₂ ^3- complex anion has an eight-coordinate structure with a distorted square antiprismatic prism. All the results including those for [Tm^III(nta)(H₂O)₂]·2H₂O confirm the inferences on the coordinate structures and coordination numbers of rare earth metal complexes with the nta ligand.     

Orthogonal Wavelets Analysis of Electroanalytical Signals

ABSTRACT

A signal processing technique based on orthogonal wavelet analysis is applied to process various simulated electroanalytical signals. The results indicate that if the scale parameters are selected, the orthogonal wavelet processing method (OWPM) can remove high-frequency noise. Experimental signal was recorded by computer and used to test the OWPM procedure. After processing with OWPM, the processed data was used to analyze the mechanism of the electrode reactions. Processed results of the experimental data are also satisfactory.     

Analytical methods to determine Po and Pb in marine samples

This paper describes the methods of sampling, preconcentration, chemical separation and final count of ²¹⁰Po and ²¹⁰Pb present in different marine matrices to determine their background levels in a marine ecosystem. Complex, time consuming and selective radioanalytical methods have been used to prepare final clear sources for alpha spectrometry and beta count; in fact, gamma spectrometry, a method direct and non destructive, cannot be taken into account because the ²¹⁰Pb activity is very low which does not allow to carry out sufficiently accurate measurements and ²¹⁰Po is not a gamma emitter but it emits only alpha particle at 5.40 MeV. The results of ²¹⁰Po and ²¹⁰Pb activity concentrations obtained in different marine samples collected in the first two campaigns are still very few to discuss about the ²¹⁰Po and ²¹⁰Pb behavior in marine environment.     

Rotational molecular motion and solvation of Na+ and Cs+ in water-dimethylacetamide. A nuclear magnetic relaxation study

Nuclear magnetic relaxation by intra- and intermolecular quadrupoleelectric field gradient interaction has been used for the study of the systems DMA-water-NaI and DMA-water-CsI at 25°C.¹⁴N relaxation of DMA and²H relaxation of D₂O measured over the complete mixture range reveal the behavior of the rotational molecular motion of the two solvent components. For both solvent components a marked maximum of the reorientational correlation time has been found, reflecting hydrophobic effects and strong DMA-water interaction. The quadrupolar relaxation rates of²³Na⁺ and¹³³Cs⁺ in pure DMA were evaluated giving an indication that the electric solvent dipoles in the solvation shell are not located on positions of cubic symmetry. A quantitative study of preferential solvation of the cations in the mixed solvent has been performed by using the H₂O-D₂O isotope effect on²³Na⁺ and¹³³Cs⁺ relaxation. For both cations an obviously typical change in the selectivity occurs. In the range l>x _{H2 O}>0.7 we find weak preferential hydration, but in the range 0.7>xH ₂ O>0 strong preferential solvation by DMA is reflected.     

A kinetic study of the oxidation of hydroxamic acids by compounds I and II of horseradish peroxidase: Effect of transition metal ions

Abstract

Oxidation of hydroxamic acids (HXs) generates HNO, and it is not clear whether it is formed also in the presence of metal ions. The kinetics of the oxidation of HXs, such as acetohydroxamic acid, suberohydroxamic acid, and suberoylanilide hydroxamic acid (SAHA), by compounds I and II of horseradish peroxidase (HRP) at pH 7.0 and 25?°C have been studied using rapid-mixing stopped-flow. The kinetics of these reactions were compared to those observed in the presence of Cu(ClO₄)₂, NiSO₄, or ZnSO₄. The rates decrease upon increasing [Cu^II] at constant [HXs], and no oxidation of HX occurs when [HX]/[Cu^II] ≈ 2, implying that HX oxidation in the presence of Cu^II proceeds through the free ligand since the predominant complex is CuX₂. In the case of Ni^II, the oxidation rate decreases upon increasing the ratio [Ni^II]/[HX] beyond 1, where the predominant complex is Ni^IIX⁺, implying that its oxidation is feasible. The effect of Zn^II could be studied only on the rate of HXs oxidation by compound II demonstrating similar behavior to that of Ni^II. HXs were also oxidized catalytically by HRP/H₂O₂ at pH 7.0, demonstrating that metal ions facilitate the formation of HNO while hardly affecting its yield and the extent of HX oxidation.     

The Synthesis of Dibenzo[3n]crown-n by Novel Methods and their Cation Binding Studied by Fluorescence Spectroscopy. Part IV

The dibenzo[3n]crown-n were synthesised from1,2-bis(o-hydroxyphenoxy)ethane obtained from 1,2-bis(o-formylphenoxy)ethane via Bayer-Willigeroxidations with H₂O₂/CH₃COOH in good yields. The cyclic condensation of 1,2-bis(o-hydroxyphenoxy)ethanewith dichlorides, and ditosylates of polyethylene glycols in DMF/Me₂CO₃ gave the macrocyclesdibenzo[15]crown-5, dibenzo[18]crown-6, dibenzo[21]crown-7 anddibenzo[24]crown-8. The structures were identified using IR, mass, ¹H and ¹³C NMR spectroscopy. Therecognition of the molecules for the cations, Li⁺, Na⁺, K⁺, Rb⁺ and Zn²⁺were conducted quantitatively with steady state fluorescencespectroscopy. The 1:1 association constants in acetonitrileshowed a good relation of the appropriate size of the macrocyclic ether towards the fitting cationradii. Namely, dibenzo[15]crown-5 was the best for Li⁺ binding and more than 100 times better thanNa⁺ and K⁺. Dibenzo[21]crown-7 was excellent for Rb⁺ binding while K⁺ is 100 timesless preferred. The largest crown ether studied, dibenzo[24]crown-8, exhibited the order of binding power,Rb⁺ > K⁺ > Na⁺. Zn²⁺ displayed, however, a marked binding with only dibenzo[18]crown-6.p>     

The preparation and analysis of fluoro-polyphosphates by F, P, 2D F-P HETCOR and 2D P-P COSY NMR

A complex mixture of fluoro-polyphosphates (FPPs) and polyphosphates was prepared by heating a mixture of NaF and sodium tripolyphosphate (STPP) at 600 °C in nitrogen atmosphere. Two-dimensional ³¹P-¹⁹F heteronuclear correlation spectroscopy (HETCOR) NMR was developed in identifying the atomic connection between F and P in the mixed FPPs. ¹⁹F, ³¹P and ³¹P-³¹P correlation spectroscopy (COSY) NMR methods were employed to identify the components of the mixture and measure the chain length of each FPP ingredient. NMR results clearly demonstrated that the mixture contains four kinds of fluoro-phosphates with different chain length of polyphosphate, which are monofluoro-phosphate (MFP), monofluoro-dipolyphosphate (MFDPP), monofluoro-tripolyphosphate (MFTPP) and difluoro-tripolyphosphate (DFTPP). Other phosphates and polyphosphates also were found in the mixture.     

Possibilities of multinuclear NMR in the chemistry of heteroorganic compounds

Results of multinuclear NMR studies of some heteroorganic compounds have been presented.According to a report at the conference «Current problems of organometallic chemistry» (May 8–13,1994, Moscow).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 614–616, April, 1994.