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A PVC membrane electrode for aluminium ion based on bis(5-phenyl azo salicylaldehyde) 2,3-naphthalene diimine (5PHAZOSALNPHN) as an ion carrier was developed. The electrode exhibits a Nernstian slope of 19.3+/-0.8 mV per decade and a linear range of 5.0x10(-6)-1.0x10(-2) M for Al(NO(3))(3). The limit of detection is 2.5x10(-6) M. It has a fast response time of about 10 s and can be used for at least 10 weeks without observing any deviation. The proposed membrane sensor revealed good selectivity for Al(3+) over a wide variety of other metal ions and could be used in pH range of 2.9-5.0. It was used as an indicator electrode in potentiometric titration of aluminium ion. 相似文献
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The syntheses, structures and spectroscopic properties of tricarbonylrhenium(I) complexes with N,N′-bis(2-bromo, 4-bromo, 4-chloro and 3-methoxybenzaldehyde)-1,2-diiminoethane Schiff base ligands have been investigated in this paper. Characterization of these complexes was carried out with FTIR, NMR, UV–Vis spectroscopy, elemental analysis and X-ray crystallography. The electrochemical behavior of the investigated complexes has been studied by cyclic voltammetry. The crystal structures of the 4-chloro, 4-bromo and 4-methoxy substituted complexes are stabilized by intermolecular C–H?Cl and C–H?O hydrogen bonds. The remarkable features of the 2-bromo, 4-bromo and 4-chloro substituted complexes are short intermolecular halogen–oxygen contacts. In the 4-bromo complex, short intermolecular Br?O and O?O contacts link neighboring molecules along the [1 0 0] direction, which are further stabilized by short intermolecular π?π interactions. In 2-bromo complex, intermolecular Br?O interactions link neighboring molecules into 1D extended chains along the [0 1 0] and [0 0 1] directions, forming a 2D network which is parallel to the bc-plane. 相似文献
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Philip. J. Davies Stephen F. Lincoln Christopher B. Smith Max R. Taylor Kevin P. Wainwright Kia S. Wallwork 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(1):28-30
Crystallization of [Cd(S‐thpc12)](ClO4)2·H2O {S‐thpc12 is 1,4,7,10‐tetrakis[(S)‐2‐hydroxypropyl]‐1,4,7,10‐tetraazacyclo‐dodecane} in the presence of sodium p‐nitrophenolate forms the title complex, [Cd(C20H44N4O4)](C6H4NO3)(ClO4)·H2O, in which p‐nitrophenolate and water separately hydrogen bond to a different pair of cis‐related pendant hydroxyl groups which, together with the four N atoms, are themselves bound to CdII in an approximately square antiprismatic arrangement. The diastereoselectivity of the complex‐forming process is apparent from the fact that both different disymmetric cations in the asymmetric unit have the same Δ helicity. 相似文献
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Reza Ranjbar-Karimi Mahtab Mashak-Shoshtari Reza Kia 《Journal of fluorine chemistry》2011,132(4):285-290
Bis-perfluoropyridyl bridged by 1,4 and 1,2 dihydropyridine compounds was synthesized by reaction of 2 and 4 aminopridine derivatives with pentafluoropyridine. The structures were determined by X-ray crystallography. Compound 3a comprises two crystallographically independent molecules in the asymmetric unit in which one of them shows 1-D infinite chains along [0 1 0] direction due to the intermolecular C-H?N hydrogen bonds. In compound 5 intermolecular C-H?F and C-H?N hydrogen bonds link neighbouring molecules to each other. In addition, in both structures a series of C-F?π interactions stabilize the crystal packing. 相似文献
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Arman Kiani-B Kia Fallahi Naser Pariz Henry Leung 《Communications in Nonlinear Science & Numerical Simulation》2009,14(3):863-879
In recent years chaotic secure communication and chaos synchronization have received ever increasing attention. In this paper, for the first time, a fractional chaotic communication method using an extended fractional Kalman filter is presented. The chaotic synchronization is implemented by the EFKF design in the presence of channel additive noise and processing noise. Encoding chaotic communication achieves a satisfactory, typical secure communication scheme. In the proposed system, security is enhanced based on spreading the signal in frequency and encrypting it in time domain. In this paper, the main advantages of using fractional order systems, increasing nonlinearity and spreading the power spectrum are highlighted. To illustrate the effectiveness of the proposed scheme, a numerical example based on the fractional Lorenz dynamical system is presented and the results are compared to the integer Lorenz system. 相似文献
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A new ammine dual-cation (Li, Mg) borohydride: synthesis, structure, and dehydrogenation enhancement
Sun W Chen X Gu Q Wallwork KS Tan Y Tang Z Yu X 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(22):6825-6834
A new ammine dual-cation borohydride, LiMg(BH(4))(3)(NH(3))(2), has been successfully synthesized simply by ball-milling of Mg(BH(4))(2) and LiBH(4)·NH(3). Structure analysis of the synthesized LiMg(BH(4))(3)(NH(3))(2) revealed that it crystallized in the space group P6(3) (no. 173) with lattice parameters of a=b=8.0002(1) ?, c=8.4276(1) ?, α=β=90°, and γ=120° at 50 °C. A three-dimensional architecture is built up through corner-connecting BH(4) units. Strong N-H···H-B dihydrogen bonds exist between the NH(3) and BH(4) units, enabling LiMg(BH(4))(3)(NH(3))(2) to undergo dehydrogenation at a much lower temperature. Dehydrogenation studies have revealed that the LiMg(BH(4))(3)(NH(3))(2)/LiBH(4) composite is able to release over 8 wt% hydrogen below 200 °C, which is comparable to that released by Mg(BH(4))(3)(NH(3))(2). More importantly, it was found that release of the byproduct NH(3) in this system can be completely suppressed by adjusting the ratio of Mg(BH(4))(2) and LiBH(4)·NH(3). This chemical control route highlights a potential method for modifying the dehydrogenation properties of other ammine borohydride systems. 相似文献
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Moayad Hossaini Sadr Behzad Soltani Alireza Jalili Faeghe Nejadghafar Reza Kia James T. Engle Christopher J. Ziegler 《Transition Metal Chemistry》2012,37(7):611-617
The novel bidentate N,S-donor anionic ligands [PhNCSIndz]?, [PhNCSImz]?, [PhNCSPzMe3]?, and [EtNCSPz]?, where Indz?=?indazole, Imz?=?imidazole, PzMe3?=?3,4,5-trimethylpyrazole, and Pz?=?pyrazole, were synthesized and used to prepare Cu(II) complexes of general formula [Cu(N^S)2]. The ligands were synthesized via direct addition of phenylisothiocyanate or ethylisothiocyanate into THF suspensions of the corresponding sodium-pyrazolate salts. All of the synthesized compounds, including the ligands and the complexes, were characterized by physico-chemical and spectroscopic methods, and crystal structures of [Cu(EtNCSPz)2] and [Cu(PhNCSPzMe2)2] were determined by X-ray diffraction analysis, showing a trans-square planar geometry for [Cu(EtNCSPz)2] and a distorted tetrahedral geometry for [Cu(PhNCSPzMe2)2]. 相似文献
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Unsymmetrical benzoN(4) nickel(II) macrocyclic complexes have been explored as an ionophore for preparing PVC-based membrane electrodes selective to SCN(-). The resulting electrode exhibited the best working concentration range (1.4x10(-7)-0.1 M) with a Nernstian slope of (-59.7+/-0.9 mV per decade) in the wide pH range of 3.5-10.5. The proposed electrode has a very fast response time (5 s) and high selectivity for thiocyanate over variety of anions. This sensor was successfully applied as an indicator electrode to potentiometric titration of thiocyanate ion with AgNO(3) and for direct determination of the amount of thiocyanate in urine and saliva samples in order to distinguish between smokers and nonsmokers. 相似文献
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The blends of polyamide 6/acrylonitrile-butadiene-styrene (PA6/ABS), with added styrene-maleic acid copolymer (SMA) compatibilizer, were prepared through melt mixing in an internal mixer. The effects of blend composition and various process conditions, as well as the addition of multi-wall carbon nanotubes (MWCNTs) to the blends, on the morphology and mechanical properties were investigated. The morphology of the blends and blend nanocomposites were observed by scanning electron microscopy (SEM) and analyzed using an image analysis technique. The mechanical behavior of the blends was investigated by tensile and also impact testing. The results showed that the blend composition as well as the processing conditions significantly affected the morphology and mechanical properties of the PA6/ABS blends. Among the various compositions, the blend with 36?wt.% of ABS and 4?wt.% of SMA compatibilizer exhibited the best mechanical properties. Comparing various speeds and times of mixing, it was found that less mixing speed and longer mixing times resulted in the favorable morphology and conditions for achievement of the desired toughness for the polyamide 6. By adding different amounts of MWCNTs to the blends, it was found that the presence of the carbon nanotubes changed the viscosity of the resulting nanocomposite and thus changed the morphology. These nanocomposites also showed an improvement in mechanical properties. The MWCNTs acted as a second compatibilizer, resulting in a synergistic effect on the mechanical properties of the PA6/ABS blend nanocomposites. 相似文献