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1.
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. 相似文献
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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 (pKa) 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. 相似文献
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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. 相似文献
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Erting Feng Ruimin Lu Congbin Fan Chunhong Zheng Shouzhi Pu 《Tetrahedron letters》2017,58(14):1390-1394
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. 相似文献
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Yang-Yang Huang Meng-Jia Wang Zheng Yang Meng-Yao She Shu Wang Ping Liu Jian-Li Li Zhen Shi 《中国化学快报》2014,25(7):1077-1081
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. 相似文献
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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. 相似文献
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Syntheses and crystal structures of four new organotin complexes with Schiff bases containing triazole 总被引:1,自引:0,他引:1
Hai-Xia Yu Guo-Hai Xu Jin Yang Yan-Xiang Cheng 《Journal of organometallic chemistry》2006,691(16):3531-3539
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. 相似文献
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Shin-Ichi Ohira Yusuke Miki Toru Matsuzaki Nao Nakamura Yu-ki Sato Yasuo Hirose Kei Toda 《Analytica chimica acta》2015
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. 相似文献
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The effect of electron-withdrawing properties of substituents on the hydrolysis of some Schiff bases
Mahmoud Abd El-Daim El-Taher 《Journal of solution chemistry》1996,25(4):401-410
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. 相似文献
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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。 相似文献
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《Journal of Coordination Chemistry》2012,65(23):3836-3846
AbstractThe 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). 相似文献
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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. 相似文献
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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. 相似文献
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光纤化学传感器分子探针的固定方法 总被引:3,自引:0,他引:3
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。 相似文献
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《Journal of Coordination Chemistry》2012,65(5):740-749
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). 相似文献
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Han Dong Yin Min Hong Qi Bao Wang Sheng Cai Xue Da Qi Wang 《Journal of organometallic chemistry》2005,690(6):1669-1676
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. 相似文献