荧光光谱法研究萘酚绿B与牛血清白蛋白相互作用特征

在不同温度下,研究了萘酚绿B(NGB)作用于牛血清白蛋白的荧光猝灭光谱、同步荧光光谱、三维荧光光谱和紫外-可见吸收光谱特征。分别用Stern-Volmer方程和Lineweaver-Burk双倒数方程等处理实验数据,证实了在试验浓度和温度范围内,NGB与BSA可相互作用形成复合物, 荧光猝灭作用符合静态猝灭作用特征,作用力主要是疏水作用力和静电作用力;得到了相互作用的相关参数K_LB,ΔHθ,ΔGθ和ΔSθ等的平均值分别为1.411×105 L·mol-1,-5.707 kJ·mol-1,-30.25 kJ·mol-1和79.95 J·K-1,结合位点数为1.258,为研究NGB对蛋白质构象的影响和在生物体内的生物学效应等提供了重要信息。     

光谱法研究1-萘酚、2-萘酚与瓜环的包结作用

用荧光光谱、紫外吸收光谱法研究了瓜环与1-萘酚、2-萘酚的相互作用,考察了pH对体系的影响。结果表明,1-萘酚、2-萘酚与六元、七元瓜环都不发生作用,而与八元瓜环发生相互作用,形成物质的量比为1∶1的稳定包结配合物。用荧光法测定1-萘酚、2-萘酚与八元瓜环包结配合物的稳定常数为4.2×104 L·mol-1和1.6×104 L·mol-1,紫外光谱法测定的稳定常数为4.2×104 L·mol-1和5.4×104 L·mol-1;在酸性和中性条件下1-萘酚、2-萘酚与八元瓜环发生包结作用,形成稳定包结物,而在强碱性条件下不发生包结作用。     

A New Emissive Chalcone-Based Chemosensor Armed by Coumarin and Naphthol with Fluorescence “Turn-on” Properties for Selective Detection of F<Superscript>−</Superscript> Ions

A new chalcone-based probe containing coumarin and naphthol at both ends has been synthesized via aldol condensation. The uniqueness of the newly derived probe can be ascribed to the presence of naphthol and coumarin units acting as binding site and signaling element, respectively. The fluorogenic behaviors toward various anions were investigated. The probe was characterized by various spectroscopic techniques and the in-depth study led to show excellent selectivity and sensitivity for fluoride ions. The hydrogen bonding thus formed with fluoride anion provides remarkable fluorometric responses. The interactions of the probe with fluoride ions were determined by fluorescence, FT-IR and NMR spectroscopic techniques. The exploratory studies by fluorescent spectral changes augur well for the naked-eye sensing applications.     

分光光度法测定生药中微量元素锌

采用湿法消解样品,用０．１％ＰＡＮ「１－２（－吡啶偶氮）２－萘酚」－２０％ＯＰ（聚乙二醇辛基苯基醚）显色分光光度法测定１０种生药中微量元素锌。     

Synthesis of trans-1,3-diaryl-2-(5-methylisoxazol-3-yl)-2,3-dihydro-1H-naphtho[1,2-e][1,3]oxazines via bismuth(III)-catalyzed one-pot pseudo-four component reaction

An expeditious, straightforward and efficient synthesis of diversely naphtho[1,2-e][1,3]oxazines via one-pot condensation reaction of ??- naphthol, 3-amino-5-methylisoxazole and arylaldehydes catalyzed by bismuth(III) trifluoromethanesulfonate is described. The reaction preferentially afforded 1,3-trans oxazines.     

双波长双指示剂催化分光光度法测定水和茶叶中的痕量锰

研究在pH 5.6的HAc-NaAc缓冲溶液中,氨三乙酸活化痕量锰离子催化高碘酸钾氧化灿烂绿和萘酚绿B的指示反应,通过测定460nm和630nm下催化体系与非催化体系吸光度值的变化,建立了双波长双指示剂催化分光光度法测定痕量锰的新方法。在最佳实验条件下,测定痕量锰离子的线性范围为0.010—0.60μg/25mL。检出限为1.2×10-10g/mL。此法用于水和茶叶中痕量锰的测定,结果满意。     

扇形叶栅叶尖间隙流动及其对叶尖换热的影响

本文通过在水槽中用粒子示踪的方法，利用最新的ＰＩＶ技术对扇形叶栅叶尖间隙泄漏流进行了定量流动显示。同时在风洞中利用萘升华传质模拟传热技术，研究了叶尖间隙区的局部换热特性结果表明泄漏流的流动特性与间隙大小、进口Ｒｅ数、攻角等密切相关，并直接影响叶尖的换热特性。     

Excited-State Proton Transfer in Hydroxynaphthaldehydes Covalently Bound to Proteins

The kinetics and equilibrium of excited-state proton transfer (ESPT) in 2-hydroxynaphthaldehyde-1 (HNA-2.1) bound to proteins (bovine serum albumin, cytochrome c, and lysozyme) by an alkylamino bond was studied by means of fluorimetric steady-state and time-resolved methods. The results were compared to analogous data for 1-hydroxy naphthaldehyde-4 (HNA-1.4) bound to proteins and for other 2-naphthol derivatives bound to proteins by a sulfonamide bond, Conclusions concerning the influence on ESPT of the mode of binding and of intramolecular hydrogen bonds occurring in the case of HNA-2. 1 were drawn. An intramolecular hydrogen bond enhances the rate of ESPT but the molecular environment in the protein leads to an opposite effect by increasing reorganization energy during proton transfer. The results obtained prove that the mode of binding and the kind of group linking fluorophores to proteins influence considerably the rate and mechanism of ESPT. In naphthol groups bound to proteins by an alkylamino bond, proton dissociation depends strongly on the molecular environment in the macromolecule. This is due to the short length of the alkylamino bridge and its small interaction with electronic orbitals of the aromatic system. Fluorophores bound to proteins by a sulfonamide bond show a higher rate of ESPT, which is due partly to the electron withdrawing effect of the linking arm. The efficiency of ESPT for naphthol groups bound to proteins by a sulfonamide bond is, in most cases, sufficient for acidification of the medium and influence of the proton gradient in biological membranes.     

2-甲基重氮萘醌在环醚中光解产物的2D NMR研究

应用二维核磁共振对2-甲基重氮萘醌在四氢呋喃和二氧六环中光解反应的产物：2-甲基-4-螺(2′-四氢吡喃)萘-1-酮 (3)、2-甲基-4-(2′-四氢呋喃基)-1- 萘酚 (4)、2-甲基-4-螺［7′-(1′,4′-二氧杂环庚烷)萘-1-酮 (5)、2-甲基-4 -［2′-(1′,4′-二氧杂环己基)］-1-萘酚 (6)和二(2-甲基-萘 -22-冠-6) (7)的¹H和¹³C NMR谱进行了全归属.     

Photodegradation of Carbaryl in Acetonitrile Solution

The photochemical decomposition, induced by UV radiation, of the carbamate pesticide (Carbaryl) in acetonitrile has been examined by means of gas chromatography–Mass spectrometry (GC‐MS). The result of continuous irradiation was almost total degradation of the pesticide examined. In order to investigate the nature of the reaction products, a spectroscopic study (UV‐Vis, steady‐state fluorescence, and fluorescence lifetime) of the products was performed. Phthalic anhydride and traces of 1,4‐naphtalenedione as an intermediate were detected as reaction products. The presence of a trace amount of 1‐naphthol as one of the photoproducts was confirmed by fluorescence lifetime measurements.     

Vibrational spectra and scaled quantum chemical studies of the structure of Martius yellow sodium salt monohydrate

The FT‐IR and Raman spectra of Martius Yellow sodium salt Monohydrate (MYM) [2, 4‐dinitro‐1‐naphthol sodium salt] in solid‐phase have been measured. The geometry, intramolecular hydrogen bonding and harmonic vibrational wavenumbers of MYM have been investigated with the help of B3LYP density functional theory (DFT) methods. The detailed interpretation of the vibrational spectra has been carried out with the aid of normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology (SQMFF). The existence of intramolecular C H···O improper, blue‐shifted hydrogen bonding was investigated by means of the NBO analysis. The infrared and Raman spectra were predicted theoretically from the calculated intensities. The observed and the calculated spectra were found to be in good agreement. Copyright © 2009 John Wiley & Sons, Ltd.     

Glass Transition Temperatures of Epoxy Modified with Pendent Nano‐Organic Rigid‐Rod Compounds

Pendent nanoscale organic rigid‐rod compounds are molecular fiber‐like materials that can be used to reinforce the polymer matrix. In this study, 4,4′‐diphenylmethane diisocyanate (MDI) was used to covalently connect a number of organic rigid‐rod compounds [4′‐hydroxyphenyl‐4‐hydroxy‐benzoate (HPHB), phenyl 4‐hydroxybenzoate (HPB), 4,4′‐isopropylidenediphenol (BSPA), and 2‐naphthol (NPT)] to the secondary hydroxyl groups of the epoxy resin. These reactions were monitored using Fourier transform infrared (FT‐IR) spectroscopy; the products were characterized using nuclear magnetic resonance (NMR) spectroscopy. The glass transition temperatures of the organic rigid‐rod compounds modified epoxy resins were investigated through differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Thermogravimetric analysis (TGA) was used to detect the values of Td and the thermal stabilities of the polymers.     

Determination of trace elements in natural water using X‐ray fluorescence spectrometry after preconcentration with powdered silica gel

A simple and cheap method is described for simultaneous determination of V, Cr, Mn, Fe, Co, Ni, Cu and Zn contents in water by means of wavelength‐dispersive X‐ray fluorescence (WDXRF) spectrometry after preconcentration. The method of preconcentration is based on sorbing analytes onto silica gel powder. 1‐(2‐pyridylazo)‐2‐naphthol (PAN) is used as a chelating agent. The effect of some parameters such as pH, temperature, stirring time, amount of ligand, breakthrough volume and the limit of detection has been studied. The detection limits 0.120, 9.75 × 10^?4, 0.075, 0.070, 0.061, 0.089, 0.029 and 0.044 mg l^?1 were achieved for V, Cr, Mn, Fe, Co, Ni, Cu and Zn, respectively. Copyright © 2009 John Wiley & Sons, Ltd.     

萘酚萘磺酸酯的核磁共振结构鉴定

叔胺基萘酚萘磺酸酯及其衍生物可以用于合成通用染料、酸性染料及阳离子染料. 本文通过操作简单、成本低廉的一步法合成该化合物. 即在碳酸钾存在下，通过7-乙酰氨基-4-羟基-2-磺酰氯与N,N-二甲基乙二胺在乙腈中反应来制备. 并通过¹H、¹³C NMR及gCOSY、TOCSY、gHMBC、gHSQC等二维核磁共振谱，完成了萘酚萘磺酸酯的¹H、¹³C的核磁共振谱线化学位移的归属，并得到相关质子的偶合常数.     

Raman spectroscopy of synthetic organic pigments used in 20th century works of art

Raman microscopy allows a non‐destructive characterisation of inorganic and organic painting materials such as pigments and organic dyestuffs. The objectives of this study are the more recent organic pigments typically present in paintings and other art works from the 20th century. More than 20 organic synthetic pigments from different chemical classes could be identified by Raman spectroscopy using different excitation wavelengths (457.9, 476.5, 487.9, 514.5, 632.8, and 1064 nm). To evaluate the performance for real paint samples, varying paint mixtures of the Hansa Yellow pigment PY 3 and the binding medium Mowilith, a polyvinyl acetate (PVAC) compound, were characterised; PY 3 was determined at a 1 wt% level in the binder. In addition, commercial tube paints containing the quinacridone violet PV 19 were studied. The pigment was clearly identified in all of these more complex oil and acrylic paints. Finally, alizarin (PR 83) and a green copper phthalocyanine pigment (PG 7) could unambiguously be identified by Raman microscopy in the painting ‘Woman with mandolin in yellow and red’ of Max Beckmann dating 1950. The discovery of a red naphthol AS pigment by Raman spectroscopy in a sample from the ‘Three field workers’ by Georg Baselitz (1964/1965) demonstrated that in some cases complementary chromatographic methods are needed for a comprehensive identification of the organic pigments. Copyright © 2008 John Wiley & Sons, Ltd.     

Sonochemical degradation of martius yellow dye in aqueous solution

The sonolytic degradation of the textile dye martius yellow, also known as either naphthol yellow or acid orange 24, was studied at various initial concentrations in water. The degradation of the dye followed first-order kinetics under the conditions examined. Based on gas chromatographic results and sonoluminescence measurements of sonicated aqueous solutions of the dye, it is concluded that pyrolysis does not play a significant role in its degradation. The chromatographic identification of hydroxy added species indicates that an OH radical induced reaction is the main degradation pathway of the dye. Considering the non-volatility and surface activity of the dye, the degradation of the dye most probably takes place at the bubble/solution interface. The quantitative and qualitative formation of the degradation intermediates and final products were monitored using HPLC and ESMS. The analytical results suggest that the sonolytic degradation of the dye proceeds via hydroxylation of the aryl ring and also by C-N bond cleavage of the chromophoric ring, either through OH radical attack or through another unidentified process. The identification of various intermediates and end products also imply that the degradation of martius yellow proceeds through multiple reaction pathways. Total organic carbon (TOC) analyses of the dye solutions at various times following sonication revealed that sonolysis was effective in the initial degradation of the parent dye but very slow in achieving mineralization. The slow rate of mineralization is likely to be due to the inability of many of the intermediate products such as, the carboxylic acids, to accumulate at the bubble (air/water) interface and undergo decomposition due to their high water solubility (low surface activity).     

2-Naphthol-phosphatidylethanolamine: A fluorescent phospholipid analogue for excited-state proton transfer studies in membranes

The fluorescence properties of the phospholipid derivative,N-[1-(2-naphthol)]-phosphatidylethanolamine (NAPH-PE), have been studied by steady-state and time-resolved fluorescence techniques. The new probe is a naphthol adduct of phosphatidylethanolamine. The emission spectrum of the fluorescent phospholipid depends on the pH and on the proton acceptor concentration as expected for a typical two-state excited-state proton transfer reaction. In ethanol solutions at an apparent pH of 6.7 and in the presence of acetate anion (0.14M), a biexponential decay is obtained from global analysis of the data. The lifetimes, ₁=3.9 ns and ₂=6.2 ns. are constant across the spectral region 350–460 nm. The decay-associated spectra and the species-associated spectra reproduce well the profiles reported for a two-state excited-state proton transfer reaction. The fluorescent phospholipid has been incorporated into dimyristoyllecithin and dipalmitoyllecithin vesicles. Although lower proton transfer is found, the reaction appears to be dependent on the gel-to-liquid-crystalline phase transition of the lipid membrane. In addition, the steady-state anisotropy of NAPH-PE measured as a function of temperature trace the phase transition of the two vesicle systems. Thus, it is shown that the physical state of the bilayer affects a reaction which takes place at the membrane surface. In the presence of acetate ions (0.3M), global analysis, performed in terms of fluorescence decay parameters, recovers preexponential coefficients that are consistent with an excited-state proton transfer reaction. The short lifetime drops from 3.9 to 0.44 ns without significant changes of the longer-lifetime component.     

The role of environment in the nonradiative relaxation of the triplet state of naphthalene derivatives in solid solutions at 77 K

The nonradiative relaxation of the triplet states of oxy-and amino-derivatives of naphthalene and conjugated ions is studied by luminescent and kinetic methods (measurements of the phosphorescence decay and of phosphorescence excitation and phosphorescence spectra) in solid solutions of ethanol-h ₆, ethanol-d ₆, and mixtures of toluene-h ₈ with piperidine-h ₁₁ at 77 K. It is found that, along with intramolecular factors, a microsolvate surrounding a molecule or an ion substantially affects the nonradiative relaxation. The contribution of this factor in ethanol increases in the series cation-polar molecule-anion and in mixtures of toluene with piperidine—with increasing piperidine concentration. The results are interpreted assuming the inductive-resonance dipole-dipole transfer of the triplet energy to the dipole acceptors of intramolecular bonds and bonds with molecules of the environment. The relative arrangement of hydrogen atoms of OH groups of ethanol molecules in microsolvates of cations and anions estimated using the inductive-resonance model agrees with the difference in the structure of solvates of oppositely charged ions, which is caused by the electrostatic charge-dipole interaction and the distribution of the electron density in the ground state of the corresponding emitting center. The inductive-resonance model was used for studying the features of solvation processes involving polar molecules. It is shown that the difference between the structures of microsolvates of 2-oxy-naphthalene molecules in solvents with close dipole moments (ethanol and piperidine) is mainly caused by the different ability of these solvent molecules to form associates. The structure of microsolvates of oxy-derivatives of naphthalene in the associated amphoteric solvent is found to depend on the number and position of substituents. In oxy-derivatives of naphthalene with spatially separated OH groups in ethano-d ₆, deuteroexchange occurs in both substituents, whereas in the naphthalene derivative with adjacent OH groups this occurs only in one of the groups. Comparison of the phosphorescence spectra of hydrogen-bond complexes and proton-transfer complexes in nonpolar solvents at 77 K revealed the existence of molecular naphthol entities in the triplet state that were formed from ionized entities in the singlet state.