以聚丙烯酰胺凝胶为基质的光导纤维pH传感器

以凝胶为基质的新型固定化试剂制备了3种pH荧光传感器.在实验条件下,其信号响应时间低于10s,pH突跃范围为1.83～7.54和1.39～2.97.基本上无试剂脱落,在试剂本身化学稳定期限内,具有一定的使用寿命.     

Wavelength encoded analytical imaging and fiber optic sensing with pH sensitive CdTe quantum dots

CdTe quantum dots (QDs), capped with mercaptopropionic acid (MPA), were synthesized and the variation of their fluorescence properties (steady state and lifetime) with pH was assessed in solution and when immobilized in a sol-gel host. Three different sizes of CdTe QDs with excited state lifetimes ranging from 42 to 48 ns and with emission maximum at 540 nm (QD₅₄₀), 580 nm (QD₅₈₀) and 625 nm (QD₆₂₅) were selected. The solution pH affects the maximum emission wavelength (shifts to higher wavelengths of 23, 24 and 27 nm for QD₅₄₀, QD₅₈₀ and QD₆₂₅, respectively), the excited state lifetime and the fluorescence intensity in a reversible way. Linearization of the maximum emission wavelength variation with the pH allows the estimation of an apparent ionization constant (pK_a) for each QD: 6.5 ± 0.1 (QD₅₄₀), 6.1 ± 0.5 (QD₅₈₀) and 5.4 ± 0.3 (QD₆₂₅). The variation of the QDs fluorescence properties was further explored using confocal laser scanning microscopy allowing the implementation of a new calibration method for pH imaging in solution. QDs were successfully immobilized on the tip of an optical fiber by dip-coating using sol-gel procedure. The immobilized QDs showed a similar pH behaviour to the one observed in solution and an apparent lifetime of 80, 68 and 99 ns, respectively. The proposed QDs based methodology can be successfully used to monitor pH using wavelength encoded data in imaging and fiber optic sensing applications.     

模式滤光光纤pH传感器的研究

采用溶胶-凝胶法将邻苯二酚紫涂覆在光纤上,然后将涂好的光纤插入毛细管中,构建新型的模式滤光光纤pH传感器.该传感器的模式滤光信号随pH的增加而降低,且在pH=6.0～9.0范围内有良好的线性关系(R=0.999),响应时间(t95％)为168 s,相对标准偏差为1.95％(n=6);而涂层中未加邻苯二酚紫的光纤传感器对...     

Recent advancement on chromo-fluorogenic sensing of aluminum(III) with Schiff bases

The consumption of non-essential aluminum ion (Al³⁺) at higher concentration from biotic and abiotic sources can cause serious adverse effects to the human body. Therefore, there is bourgeoning need of developing facile analytical methods for the on-site and real-time monitoring of Al³⁺ concentration in various environmental and biological samples. The chromo-fluorogenic based sensors have been widely developed in the recent years to detect and monitor Al³⁺ ion. Among the various types of developed chemical sensors, the Schiff bases proved to have several advantages due to their facile synthesis with high yield, fascinating coordination behavior and easy structural modification. This review was narrated to compile the Schiff bases introduced recently for the sensing of Al³⁺ in various environmental and biological samples. The designing of sensor, sensing mechanisms and other analytical novelties of the developed sensors are discussed.     

A fluorescent sensor for Al3+ based on a photochromic diarylethene with a hydrazinobenzothiazole Schiff base unit

A new fluorescent turn-on chemosensor for Al³⁺ based on a diarylethene unit was designed and synthesized. Photochromism, fluorescence switch, and metal ion recognition behaviors of this diarylethene derivative were investigated by absorption and fluorescence emission spectra. It shows an outstanding fluorometric sensing ability toward Al³⁺ ion, and the detection limit was measured to be 9.3 × 10^?8 mol L^?1 via fluorescence methods. Based on these interesting properties, a combinational logic circuit was constructed successfully.     

High efficient probes with Schiff base functional receptors for hypochlorite sensing under physiological conditions

A series of novel and convenient fluorescent probes with Schiff base functionality were presented for direct detection of OCI via the irreversible OCl-promoted oxidation and hydrolyzation reaction in formation of the ring-opened product, fluorescein. Prominent high sensitivity, selectivity and antiinterference OCl-induced fluorescence and color change over a wide range of tested metal ions performance were observed for each probe under physiological conditions, thus making the probes well suitable for sensing of OCl in living cells.     

1-[1-(4-氯苯基)环丁基]-3-甲基丁胺席夫碱的合成、表征及晶体结构

采用减肥药盐酸西布曲明的中间体1-[1-(4-氯苯基)环丁基]-3-甲基丁胺分别与水杨醛、3,5-二氯水杨醛缩合,得到相应的席夫碱化合物2-[[1-[1-(4-氯苯基)环丁基]-3-甲基丁亚氨基]甲基]苯酚(1)和2,4-二氯-6-[[1-[1-(4-氯苯基)环丁基]-3-甲基丁亚氨基]甲基]苯酚(2).通过单晶X-射线衍射、红外光谱、核磁共振谱、元素分析等表征确定了两个席夫碱化合物的组成及结构.1是单斜晶体,空间群C2/c.2是三斜晶体,空间群P-1.化合物主要通过氢键或π-π相互作用形成超分子结构.两个席夫碱化合物具有相似的荧光性质,是潜在多功能蓝色荧光材料.     

Syntheses and crystal structures of four new organotin complexes with Schiff bases containing triazole

Four new organotin complexes, namely [(Bu₂Sn)₂O(EtO)(L1)]₂ (1), [(Bu₂Sn)₂O(EtO)(L2)]₂ (2), [(Bu₂Sn)₂O(EtO)(L3)]₂ (3) and [Ph₃Sn(L4)] · 0.5H₂O (4), were obtained by reactions of Bu₂SnO and Ph₃SnOH with 4-phenylideneamino-3-methyl-1,2,4-triazole-5-thione (HL1), 4-furfuralideneamino-3-methyl-1,2,4-triazole-5-thione (HL2), 4-(2-thienylideneamino)-3-ethyl-1,2,4 -triazole-5-thione (HL3) and 4-(3,5-di-t-butylsalicylideneamino)-3-ethyl-1,2,4-triazole-5-thione (HL4). Compounds 1-4 were characterized by elemental analysis, IR spectra and their structures were determined by single-crystal X-ray diffraction methods. Complexes 1-3 show similar structures containing a Sn₄O₄ ladder skeleton in which each of the exo tin atoms is bonded to the N atom of a corresponding thione-form deprotonated ligand. Complex 4 shows a mononuclear structure in which the tin atom of triphenyltin group is coordinated by the S atom of a thiol-form L4⁻ anion.     

光纤传感技术在腐蚀监测中的应用

本文全面介绍了利用光纤传感技术检测与材料腐蚀相关参数的检测方法和应用状况;系统地分析了各项技术的优缺点及国内外发展状况;明确提出参数的综合检测是材料所处环境的腐蚀状况的全面评估措施,它为腐蚀防护提供了理论依据。     

A fiber optic sensor with a metal organic framework as a sensing material for trace levels of water in industrial gases

Industrial gases such as nitrogen, oxygen, argon, and helium are easily contaminated with water during production, transfer and use, because there is a high volume fraction of water in the atmosphere (approximately 1.2% estimated with the average annual atmospheric temperature and relative humidity). Even trace water (<1 parts per million by volume (ppmv) of H₂O, dew point < −76 °C) in the industrial gases can cause quality problems in the process such as production of semiconductors. Therefore, it is important to monitor and to control trace water levels in industrial gases at each supplying step, and especially during their use. In the present study, a fiber optic gas sensor was investigated for monitoring trace water levels in industrial gases. The sensor consists of a film containing a metal organic framework (MOF). MOFs are made of metals coordinated to organic ligands, and have mesoscale pores that adsorb gas molecules. When the MOF, copper benzene-1,3,5-tricarboxylate (Cu-BTC), was used as a sensing material, we investigated the color of Cu-BTC with water adsorption changed both in depth and tone. Cu-BTC crystals appeared deep blue in dry gases, and then changed to light blue in wet gases. An optical gas sensor with the Cu-BTC film was developed using a light emitting diode as the light source and a photodiode as the light intensity detector. The sensor showed a reversible response to trace water, did not require heating to remove the adsorbed water molecules. The sample gas flow rate did not affect the sensitivity. The obtained limit of detection was 40 parts per billion by volume (ppbv). The response time for sample gas containing 2.5 ppmvH₂O was 23 s. The standard deviation obtained for daily analysis of 1.0 ppmvH₂O standard gas over 20 days was 9%. Furthermore, the type of industrial gas did not affect the sensitivity. These properties mean the sensor will be applicable to trace water detection in various industrial gases.     

The effect of electron-withdrawing properties of substituents on the hydrolysis of some Schiff bases

The dissociation kinetics of the Schiff bases investigated in the present paper [N,N-bis(X-benzylidenes)ethylenediamine], have been examined under basic and acidic conditions, in aqueous medium 25% acetone in water (wt-wt). The base hydrolysis reaction of these compounds was found to follow second-order kinetics, first-order with respect to each of the Schiff base and the hydroxide ions. The rate-determining step is suggested to be the hydroxide ions attack on the free base. The effect of acetone ratio, in hydrolysis medium, has been studied under alkaline conditions. It is deduced that both the hydrogen bonding formation and solvent-solvent interaction have a pronounced role in such hydrolysis reactions. The acid hydrolysis reaction is strictly second-order kinetics, first-order with respect to the Schiff base and also to the hydrogen ions, and the attack of water molecules on the protonated substrate becomes the rate-determining step. A slower rate of the base hydrolysis was observed through the Schiff base II (p-NO₂), on the other hand, a fast acid hydrolysis rate was detected in the case of compound III (p-COOH). Furthermore, from the effect of temperature on the reaction rate, the various thermodynamic parameters have been also calculated and discussed.     

基于4-(N, N-二乙氨基)水杨醛席夫碱类荧光探针的研究进展

4-(N,N-二乙氨基)水杨醛是染料及有机合成的重要中间体,也是具有亲水性质的生色团,其醛基常被用来制备席夫碱进而开发新颖的探针分子。本文介绍了对于一些常见离子如Al~(3+)、Cu~(2+)、Zn~(2+)、Hg~(2+)、Co~(2+)、F~-、CN~-等进行荧光识别和检测的基于4-(N,N-二乙氨基)水杨醛合成的席夫碱类荧光探针,这些探针具有较高的选择性和灵敏度,并有很好的细胞通透性和较低的细胞毒性,有一定的实用价值。本文为此类荧光探针在环境、生物、食品中的实际检测和应用研究提供了理论依据和实践基础。     

Influence of substituent effects on the coordination ability of salicylaldehyde Schiff bases

Abstract

The logK₁ was quantified by four parameters, metal ion radii R, metal ion charge Q, metal atom polarizability P, and Hammett constants σ of substituent, where logK₁ was the stability constant of complexes (179) involving 10 Schiff bases Sal-A-X (N-(5-chloro-4-6-dimethyl-benzylidene)-anilines) reacting with 18 metal ions. The effect of substituents on the coordination ability of Sal-A-X was systematically investigated, and an expression with good correlation was obtained. The result shows that the electronic effect of substituent X on the aniline ring has an important influence on the stability of the complex; its electron-donating effect enhances the stability of the complex, whereas its electron-withdrawing effect lowers the stability of the complex. The theoretical results provide a potential value for the design of coordination compounds with unique function and reactivity. Moreover, their coordination selectivity to specific metal-ions can also be evaluated according to Equation (2).     

EPR character of gadolinium complexes with noncyclic polyether Schiff bases and its solvent effects

EPR characters of three new gadolinium complexes with noncydic polyether Schiff bases in powder or organic solvents, including various oxyethylene chain lengths and different substituting groups in ligands, are investigated respectively. Some regularities are summed up. The difference of EPR character in various solvents, particularly at different temperatures, has been examined. The 'single peak effect' due to THF solvent at low temperature is observed for the first time. This phenomenon is explicated.     

N-1,3,4-噻二唑-2-基取代Schiff碱的合成及光学性质研究

本文以对甲苯磺酸为催化剂,通过2-氨基-5-烃基-1,3,4-噻二唑与水杨醛的反应合成了一系列N-1,3,4-噻二唑-2-基取代Schiff碱类化合物2,利用IR,1H NMR,13C NMR和元素分析表征了化合物的结构。采用紫外光谱和荧光光谱研究了化合物的光谱性能,结果表明,所合成的化合物2具有较强的荧光发射光谱,λem为554～573 nm。     

Synthesis,spectroscopic characterization and catalytic activity of cis-dioxidomolybdenum (VI) complexes with chiral tetradentate Schiff bases

New chiral mononuclear cis-dioxidomolybdenum (VI) complexes, MoO ₂ L ¹ –MoO ₂ L ¹⁰ , with tetradentate Schiff bases derived from various substituted salicylaldehydes and 1S,2S-(+)-2-amino-1-(4-nitrophenyl)-1,3-propanediol were synthesized. All complexes were characterized by elemental analysis, circular dichroism, electronic and IR spectroscopy. ¹H NMR and also two-dimensional (COSY, NOESY and gHSQC) NMR measurements made for MoO ₂ L ¹ –MoO ₂ L ¹⁰ complexes show that Schiff bases are coordinated to the MoO₂²⁺ cation, creating facial (fac) and meridional (mer) types of geometrical isomers. Moreover, catalytic activity studies were also performed for all complexes in asymmetric sulfoxidation of thioanisole and epoxidation of styrene, cyclohexene and two monoterpenes, i.e. S(−)-limonene and (−)-α-pinene, using aqueous 30% H₂O₂ or tert-butyl hydroperoxide as the oxygen source.     

光纤化学传感器分子探针的固定方法

本文综述分子探针在光纤化学传感器探头上的固定方法,按照其结合方式可分为物理方法和化学方法,分别综述了它们的特点及实际。引用文献２４篇。     

Photochemical reactions of group VIB metal carbonyls with heterocyclic Schiff bases derived from 4-amino -3-hydrazino-5-mercapto-1,2,4-triazole

The new complexes, M(CO)₅(Schiff base) [M?=?Cr; 1, Mo; 2, W; 3, Schiff base?=?4-salicylidenamino-3-hydrazino-5-mercapto-1,2,4-triazole, SAHMT, a; 4-(2-hydroxynaphthylidenamino)-3-hydrazino-5-mercapto-1,2,4-triazole, 2HNAHMT, b; 4-(3-hydroxybenzylidenamino)-3-hydrazino-5-mercapto-1,2,4- triazole, 3HBAHMT, c; 4-(4-hydroxybenzylidenamino)-3-hydrazino-5-mercapto-1,2,4- triazole, 4HBAHMT, d; 4-(5-bromosalicylidenamino)-3-hydrazino-5-mercapto-1,2,4-triazole, 5BrSAHMT, e; were synthesized by photochemical reaction of metal carbonyls M(CO)₆ (M?=?Cr, Mo, W) with new heterocyclic Schiff bases derived from 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole, a–e. The ligands and complexes have been characterized by elemental analysis, EI-mass spectrometry, FT-IR, ¹H and ¹³C-{¹H}-NMR spectroscopy. The spectroscopic studies show that Schiff bases, a–e, are monodentate and coordinate via azomethine N donor to the central metal atom in M(CO)₅(Schiff base) (M?=?Cr, Mo, W).     

Synthesis and structural characterization of diorganotin(IV) esters with pyruvic acid isonicotinyl hydrazone and pyruvic acid salicylhydrazone Schiff bases

Eight diorganotin esters of Schiff base ligands formulated as [R₂SnLY]₂, where L₁ is 4-NC₅H₄CON₂C(CH₃) CO₂ with Y = H₂O, R = Ph (1), PhCH₂ (2), m-ClC₆H₄CH₂ (3), and L₂ is 2-HOC₆H₄CON₂C(CH₃) CO₂ with Y = CH₃OH, R = PhCH₂ (4), o-ClC₆H₄CH₂ (5), m-ClC₆H₄CH₂ (6), o-FC₆H₄CH₂ (7), p-FC₆H₄CH₂ (8) have been prepared and characterized by elemental analysis, IR, ¹H and ¹¹⁹Sn NMR spectra. The crystal structures of compounds 1, 2 and 4 have been determined by X-ray single crystal diffraction. Their structures show that the tin atoms of three compounds are all rendered seven-coordinated in distorted pentagonal bipyramid geometries with a planar SnO₄N unit and two apical aryl carbon atoms. A comparison of the IR spectra of the ligands with those of the corresponding compounds, reveals that the disappearance of the bands assigned to carbonyl unambiguously conforms that the ligands coordinate with tin in the enol form.