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31.
流动注射分光光度法测定微量硫氰酸根 总被引:2,自引:0,他引:2
基于3,5-Br2-PADAP硫氰酸根分别与重铬酸根,铈(IV)在硫酸介质中反应成不稳定的蓝色产物,建立了两种测定微量硫氰酸根的流动注射分光光度新方法,在前一方法中,硫氰酸根含量在0.80~7.20mg/L范围内可定量测定,检出限为0.27mg/L在后一方法中,硫氰酸根含量在0.80~6.40mg/L范围内呈线性,检出限为0.30mg/L。当进样体积为100μL时,进样频率为60次/h,所建立的两 相似文献
32.
Rory?H.?Uibel Emily?C.?Heider Jennifer?L.?Gasser Joel?M.?HarrisEmail author Edward?M.?Eyring Sergio?Petrucci 《Journal of solution chemistry》2005,34(5):499-514
Advances have been made recently in broadening the accessible ultrasonic absorption frequency range and improving the detectability of minor species present in solution using Raman spectroscopy. Development of chemometric techniques in these areas needs to keep pace with the improvement of these experimental methods. Refinements in the analysis of ultrasonic and Raman data based on multivariable least squares and factor analysis, respectively, are examined to investigate the kinetics of zinc thiocyanate complex formation in water. Analysis of ultrasonic absorption relaxation spectra verified that the observed process in aqueous Zn(SCN)2 involves substitution of water from the first coordination shell of Zn2+. Use of a multivariable least-squares error surface is described that enhances the reliability of assigned frequencies of ultrasonic absorption maxima. Factor analysis of Raman scattering data provided direct evidence that at least four complex species, such as Zn(SCN)+ and Zn(SCN)2, are simultaneously present in the aqueous zinc thiocyanate solutions. 相似文献
33.
Mark Salomon 《Journal of solution chemistry》1990,19(12):1225-1236
Conductivity data are used to determine thermodynamic complex formation constants for cases in which both the initial electrolyte and the complexed electrolyte form ion pairs. Using the method described in the text, the complex formation constants of Li+, Na+ and K+ with the crown ether 18-crown-6 and of Li+ with the ligand triphenylphosphine oxide in propylene carbonate have been evaluated from conductance data. The complexation of AgBr in propylene carbonate solutions of n-etrabutylammonium bromide has also been studied by the measurement of molar conductivities. The results of these studies indicate that ion pairing should not be neglected, even in high permittivity solvents such as propylene carbonate, and that the ion pair association constants correlate well with structural studies on cation-crown ether molecular conformations. 相似文献
34.
新型双核铜金属配合物为中性载体的硫氰酸根离子高选择性电极的研究 总被引:8,自引:0,他引:8
研制了基于N,N'-亚乙基(μ-5,5-亚甲基-二水杨醛根)(乙酰丙酮根)合二铜(II) [Cu2(II)-MDSBAE]金属配合物为中性载体的阴离子选择性电极. 试验表明, 以Cu2(II)-MDSBAE金属配合物为中性载体的电极对SCN-具有良好的电位响应特性, 且呈现反Hofmeister行为,其选择性序列为: SCN->Sal->I->ClO4->NO3->Br->NO2->Cl-≈SO32->SO42-. 在pH 5.0的磷酸盐缓冲体系中, 电极电位呈现近能斯特响应, 线性响应范围为1.0×10-6~1.0×10-1 mol/L, 斜率为-53. 6 mV/dec (25 ℃), 检测下限为8.1×10-7 mol/L. 用交流阻抗研究了电极的响应机理, 并用紫外可见光谱技术测定了电极载体与SCN-, Sal-, I-, ClO4-和NO3-离子间的配位数及缔合常数. 将该电极用于实验室废水和工业废水中硫氰酸根的检测, 其结果令人满意. 相似文献
35.
One-pot reactions of cadmium(II) perchlorate/nitrate, Schiff bases (pbap/pfap) and pseudohalides (sodium azide/ammonium thiocyanate) in a 2:1:4 molar ratio in MeOH–MeCN solvent mixtures at room temperature result in a dinuclear compound [Cd2(pbap)(OH2)2(N3)4] (1) [pbap = N-(1-pyridin-2-ylbenzylidene)-N-[2-(4-{2-[(1-pyridin-2-ylbenzylidene)amino]ethyl}piperazin-1-yl)ethyl]amine] and a polymeric compound [Cd2(pfap)(μ1,3-NCS)(μ1,3-SCN)(NCS)2]n (2) [pfap = N-(1-pyridin-2-ylformylidene)-N-[2-(4-{2-[(1-pyridin-2ylformylidene)amino]ethyl}piperazin-1-yl)ethyl]-amine]. X-ray crystal structural analyses reveal a bis(tridentate) congregation behaviour of the hexadentate blocker (pbap/pfap) encapsulating two metal centers. Each cadmium(II) center in 1 and 2 is in a distorted octahedral geometry with CdN5O and CdN5S chromophores, respectively. In 1, the dinuclear units participate in intermolecular O–H?N hydrogen bonding between bound water O atoms and terminal azide N atoms, in combination with C–H?π interactions, resulting in a 3D supramolecular network with an intramolecular Cd?Cd distance of 6.473(2) Å. In the crystal lattice, the covalent 1D chain of 2 is further engaged in face-to-face π?π interactions from two terminal pyridine rings, which stabilizes the chain with an intradimer Cd?Cd separation of 6.640(5) Å. Both the complexes display intraligand 1(π–π∗) fluorescence and intraligand 3(π–π∗) phosphorescence in glassy solutions. 相似文献
36.
Highly selective poly(vinyl chloride) (PVC) membrane electrode based on N-salicylidene-benzylamineato copper(II) complexes
[Cu(SBA)2] as new carriers towards thiocyanate-selective electrode was reported. The influence of membrane composition, pH and possible
interfering anions were investigated on the response properties of the electrode. The resulting electrode exhibits anti-Hofmeister
selectivity sequence: SCN− > ClO4− > Sal− > I− > Br− > NO3− > NO2− > SO32− > H2PO4− > Cl− > SO42−, and a near-Nernstian potential linear range for thiocyanate from 1.0 × 10−1 to 9.0 × 10−7 M with a detection limit of 7.0 10−7 M and a slope of , over a wide pH range of 3.0–9.0 in phosphate buffer solution at 20°C. The proposed electrode has a fast response time of
about 5–10 s and can be used for at least 3 months without any considerable divergence in potential. The electrode was successfully
applied to the determination of thiocyanate in waste water and human urine and saliva samples.
Published in Russian in Elektrokhimiya, 2008, Vol. 44, No. 3, pp. 293–299.
The text was submitted by the authors in English. 相似文献
37.
Hui‐Ting Wang Qiang Li Lin Zhou 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(9):763-767
A cadmium–thiocyanate complex, poly[(1‐cyanomethyl‐4‐aza‐1‐azoniabicyclo[2.2.2]octane‐κ4N)octakis‐μ2‐thiocyanato‐κ8N:S;κ8S:N‐tricadmium(II)], [Cd3(C8H14N3)2(NCS)8]n, was synthesized by the reaction of 1‐cyanomethyl‐4‐aza‐1‐azoniabicyclo[2.2.2]octane chloride, cadmium nitrate tetrahydrate and potassium thiocyanide in aqueous solution. In the crystal structure, there are two independent types of CdII cation (one on a centre of inversion and one in a general position) and both are in distorted octahedral coordination environments, coordinated by N and S atoms from different ligands. Neighbouring CdII cations are linked together by thiocyanate bridges to form a two‐dimensional network. Hydrogen‐bonding interactions are involved in the formation of a three‐dimensional supramolecular network. 相似文献
38.
运用密度泛函理论方法研究了烷基碳链长度对氯化三烷基铵络合氯化汞的影响,计算结果表明,氯化三烷基铵与氯化汞的络合作用随着氯化三烷基铵中烷基碳链的增长而增强.通过对络合物的键长、Mayer键级和Mulliken电荷分析可知,电子富集在氯化三烷基铵的Cl原子上,并和Hg原子之间形成静电吸引作用.当烷基长度小于3时,烷基的电子效应影响较为明显,增强了原子之间的电子转移,使得络合物更稳定;当氯化三烷基铵烷基碳链长度大于3后,烷基链长对络合物中的电子转移不再有影响,络合物的稳定性受到烷基的几何效应影响更为明显. 相似文献
39.
40.
Ethylene diamine (EDA)/salt solvent systems can dissolve cellulose without any pretreatment. A comparison of the electrical
conductivity of different salts in EDA was made at 25 °C, and conductivity decreased in the order of KSCN>KI>NaSCN at the
same molar concentration. Among the salts tested, potassium thiocyanate (KSCN) was capable of dissolving both high molecular
weight (DP>1000) and low molecular weight (DP = 210) cellulose, and this was confirmed by polarized light microscopy. 39K and 14N NMR experiments were conducted at 70 °C as a function of cellobiose concentration with EDA/KSCN as the solvent. The results
showed that the K+ ion interacts with cellobiose more than the SCN− ion does. Recovered cellulose was studied by infrared spectroscopy (FTIR) and wide angle X-ray diffraction (WAXD). Changes
in the FTIR absorption bands at 1,430 and 1,317 cm−1 were associated with a change in the conformation of the C-6CH2OH group. The changes in positions and/or intensities of absorption bands at 2,900, 1,163, and 8,97cm−1 were related to the breaking of hydrogen bonds in cellulose. X-ray diffraction studies revealed that cellulose, recovered
by precipitating cellulose solutions with water, underwent a polymorphic transformation from cellulose I to cellulose II. 相似文献