共查询到20条相似文献,搜索用时 46 毫秒
1.
A novel flow cell for use with ion-selective membrane electrodes is reported in which the carrier stream is drawn through a tube that suppresses the pump noise. PVC membrane electrodes based on 7,16-dithenoyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (DTODC), and 7,16-di-(2-thiopheneacetyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (DTAODC) for lead (II), and 7,16-dithenyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (DTDC) and 7,16-di-(2-methylquinolyl)-1,4,10,13-tertraoxa-7,16-diazacyclootadecane (DQDC), for mercury (II) were prepared and evaluated. The linear ranges were pPb: 5.5-3.0 (DTODC) and 6.0-2.0 (DTAODC); pHg: 5.5-3.0 (DTDC) and 4.5-2.5 (DQDC). With flow rate of 3 ml min(-1) the repeatability of measurements was less than 5% RSD (n = 3). The system was applied to the determination of lead (II) and mercury (II) in spiked natural water samples. 相似文献
2.
The syntheses of phenol-containing diazamacrocycles and liquid membrane transports of alkali cations
Shu-Lan Ma Xiao-Zhu Wang Cui-Hong Fan Qian-Ling Guo Wen-Xiang Zhu Jing Zhang 《Journal of Molecular Structure》2007,846(1-3):23-27
Two new bisphenol-containing diazacrown ether derivatives, 7,16-bis(2-hydroxy-5-ethylbenzoatebenzyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (1) and 7,16-bis(2-hydroxy-3,4-dimethylbenzyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (2), have been synthesized via one-pot Mannich reaction. The compound 1 is structurally characterized. The liquid membrane transports of alkali metal cations using these two new diazamacrocycles and the other previously prepared diazamacrocyclic derivative 7,16-bis(3-hydroxy-6-methyl-2-pyridylmethyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (3) as ion-carriers are also studied. The results show that the rates of cation transports are closely related to the number of nitrogen donors and the steric effect of the substituted groups. Compared with other macrocyclic compounds, compound 1 shows a good selectivity for Li+, therefore providing a new efficient carrier for Li+ extraction. 相似文献
3.
《Journal of Molecular Structure》2002,602(1-3):141-146
A lariat crown ether compound 7,16-bis(2-hydroxy-5-methylbenzyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane has been prepared via one-pot Mannich reaction. A copper(II) complex with the ligand 7,16-bis(2-hydroxy-5-methyl-3-nitrobenzyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane was unexpectedly synthesized and characterized by elemental analysis, IR and UV spectra. The crystal structure of the complex has been determined by X-ray diffraction. Both crystal structure analysis and spectroscopy study indicated that the side-arm phenols of lariat crown ether are nitrated while complexing with Cu(NO3)2. Structure shows that the copper(II) ion is coordinated to two nitrogen and four oxygen atoms, two from the crown ether and other two from the deprotonated phenolate groups. The coordination polyhedron is a distorted octahedron. 相似文献
4.
Rahul M. Kotkar Ashwini K. Srivastava 《Journal of inclusion phenomena and macrocyclic chemistry》2008,60(3-4):271-279
The electrochemical behavior of nicotinamide was studied at a carbon paste electrode and the electrodes modified with macrocyclic
compounds using voltammetric and impedance measurements. The electrodes so formed were able to bind nicotinamide ions chemically
and gave better voltammetric responses than the unmodified ones. The macrocycles used as modifiers for the electrode preparation
were 18-crown-6, dicyclohexano-18-crown-6, dibenzo-18-crown-6, 7,16-dibenzyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane,
1,4,7,10,13,16-hexathiacyclooctadecane (Hexathia), 1,4,7,10-tetratosyl-1,4,7,10-tetraazacyclododecane, 1,4,8,11-tetraazacyclooctadecane,
c-Methylcalix[4]resorcenarene and calix[8]arene. Among these macrocyclic modified electrodes, hexathia showed more affinity
towards nicotinamide and a 2.3-fold increase in voltammetric signal was obtained. Impedance measurement was used to confirm
this enhancement observed on modified electrode. This increase in anodic peak current was then used for finding linear working
range, which was 0.1–500 μg mL−1 with a detection limit of 0.03 μg mL−1 by DPV. Interference from other vitamins like thiamine HCl (Vit. B1), riboflavin (Vit. B2), pyridoxine HCl (Vit. B6) cynocobamine (Vit. B12), para-aminobenzoic acid (PABA) and ascorbic acid (Vit. C) was also studied. The modified electrode could be used for the simultaneous
determination of riboflavin, nicotinamide and pyridoxine HCl. It has also been utilized for the analysis of nicotinamide in
pharmaceutical preparations. 相似文献
5.
Synthesis and Crystal Structure of the Copper Complex of 7,16-Bis(2-hyd roxy-5-met hylbenzyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane 总被引:1,自引:0,他引:1
A lariat crown ether ligand 7,16-bis (2-hydroxy-5-methylbenzyl)- 1,4,10,13-tetraoxa-7,16-diazacyclooctadeeane (L1) has been prepared via one-pot Mannich reaction. Its copper(Ⅱ) complex Cu-L1 was synthesized and characterized by elemental analysis, IR and UV-visible spectroscopy. The crystal structure of the complex has been determined by X-ray diffraction analysis. The result shows that the copper(Ⅱ) ion is six-coordinated by two nitrogen and four oxygen atoms, two from the crown ether and the other two from the deprotonated phenolate anions, forming an elongated octahedral complex. Electrochemical study indicates that the complex undergoes reversible reduction in DMF solution. 相似文献
6.
A new PVC membrane electrode for the triiodide ion based on a charge-transfer complex of iodine with 7,16-dibenzyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane as a membrane carrier was prepared. The electrode exhibits a Nernstian response for triiodide ions over a wide concentration range (1.0 x 10(-1)-1.0 x 10(-5) M) with a slope of 59.3 +/- 0.9 mV decade(-1) and a detection limit of 6.3 x 10(-6) M. It has a response time of 30 s and can be used for at least 3 months without any divergence in the potential. The potentiometric response is independent of the pH, in the pH range 1.6 - 10.0. The proposed electrode has shown very high selectivity for the triiodide ion over a wide variety of other anions. This electrode was successfully applied as an indicator electrode in the potentiometric titration of ascorbic acid and hydroquinone from pharmaceutical preparations as well as ascorbic acid in orange juice and dissolved O2 in tap water. 相似文献
7.
Iványi T Pál K Lázár I Massart DL Vander Heyden Y 《Journal of chromatography. A》2004,1028(2):325-332
Two new diaza-crown ether derivatives (R-1, RS-1) have been synthesized from 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane and tested as potential chiral selectors in capillary electrophoresis (CE) for the chiral separation of five amino acid derivatives. The individual use of the selectors did not lead to chiral differentiation. However, they enhanced the enantioselective effect of different cyclodextrins in dual selector systems. In this paper, we report the effect of different substituted diaza-crown ether derivatives on the separation results obtained in dual systems with cyclodextrins. 相似文献
8.
E. Sonveaux 《Tetrahedron》1984,40(4):793-797
Various N,N'-diaryl derivatives of l,4,10,13-tetraoxa-7,16-diazacyclooctadecane were synthesized. 7,16-diphenyl-l,4,10,13-tetraoxa-7,16-diazacyclooctad On the contrary, diamide derivatives of 7,16-di[(2-amino)phenyl]-l,4,10,13-tetraoxa-7,16- diazacyclooctadecane were deprotonated by Cu(II) and formed stable chelates. Spectral data suggest that monodeprotonation gives dissymmetric 1:1-complexes and dideprotonation gives symmetric 1: 1-complexes. 相似文献
9.
Electrospray ionization mass spectrometry is used for the measurement of binding selectivities of four model hosts, 18-crown-6, dibenzo-18-crown-6, dicyclohexano-18-crown-6, and 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane, for both alkali and transition metal ions. Based on the intensities of the metal complexes observed in the mass spectra, the relative binding selectivities can be directly estimated. Results are compared to theoretical selectivities obtained by solving simultaneous equilibria equations that define the competing complexation reactions in solution. Good agreement is found in most cases, thus allowing rapid determination of binding selectivities of hosts in a variety of solvents. 相似文献
10.
Polyaniline (PANI) chemically coated on polyvinylchloride (PVC) membrane based on a neutral carrier 7,16-didecyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (Kryptofix 22 DD) as the active component has been developed for determination of pH values ranging from pH 0.1–1. Effect of experimental parameters such as membrane composition, nature and amount of plasticizer, lipophilic additives and thickness of PANI film on the potential response of the pH electrode was investigated. The electrode has an apparent Nernstian response slope of 54.5 ± 0.4 mV/pH (at 20°C). The equilibrium water content of the electrode was determined in pure water and NaCl solution (I = 0.1 mol/kg). The electrode had low electric resistance, good potential stability and reproducibility (±1.5 mV, n = 10). It had a rapid potential response to changes of pH (15 s). The excellent performance in terms of linearity, stability and fast response makes this device suitable for pH measurements in highly acidic media. 相似文献
11.
The use of a positively charged diazacrown ether, N,N,N',N'-tetramethyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane dichloride (1), in capillary electrophoresis is reported, for the first time. The addition of the cationic diazacrown 1 to the running buffer permitted the successful separation of positional isomers of aromatic anions such as naphthalenedisulfonate, naphthalenedicarboxylate and phthalate. At a concentration of 1 of 2 mM, all the analyte anions were completely separated in less than 5 min. The ion association constants of the solute anions with diazacrown 1 were evaluated and the findings are discussed. 相似文献
12.
The solvent extraction of univalent metal cations with N,N'-dibenzyl-1,4,10,13-tetraoxa-7,16 diaza-2,3,11,12-dibenzocycloocta deca-2,11-diene (L(1)), N,N' didodecyl-1,4,10,13-tetraoxa-7,16-diaza-2,3-benzocylooctadeca-2 ene (L(2)) and N,N'-dibenzyl-1,4,10,13-tetraoxa-7,16 diaza-2,3,11,12-dibenzocyclo octadeca-2,11-diene (L(3)) with picrate anion into dichloromethane has been studied at 25 degrees C by UV-visible spectroscopy. The extractability and selectivity of univalent metal picrates (Li(+), Na(+), Ag(+), PhCH(2)NH(3)(+), NH(4)(+)) was evaluated as a function of [ligand]/[metal cation]. L(2) showed the highest extractability and selectivity for Li(+) over the larger studied cations, and also exhibited the highest [Li(+)]/[NH(4)(+)] selectivity as L/M=1. 相似文献
13.
Reaction of HgSO4 with one molar equivalent of L{L = [18]aneN2S4 (1,4,10,13-tetrathia-7,16-diazacyclooctadecane) or Me2[18]aneN2S4 (7,16-dimethyl-1,4,10,13-tetrathia-7,16-diazacyclooctadecane)} in refluxing MeOH-H2O for 15 min affords a colourless solution containing the complex cation [Hg(L)]2+. Addition of excess PF6− counterion gives the complex [Hg([18]aneN2S4)](PF6)2·4/3H2O as a cream coloured solid. A single crystal X-ray structure determination shows mercury(II) bound to a severely distorted octahedral arrangement of the six macrocyclic donor atoms, Hg---S = 2.655(5), 2.735(4), 2.751(4), 2.639(5) Å, Hg---N = 2.473(11), 2.472(17) Å. The cation is in a rac configuration with the two SCH2CH2NCH2CH2S linkages bound meridionally to the metal centre. 相似文献
14.
《Polyhedron》2003,22(25-26):3249-3253
Reaction of the crown ether ligand H2L (H2L=7,16-bis (5-t-butyl-2-hydroxybenzyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane) with Cu(Ac)2 and Cu(NO3)2 affords complexes 1 and 2, respectively, which are characterized by elemental analysis, IR and UV–Visible spectroscopy and X-ray diffraction. Both crystal structure analysis and spectroscopy study unexpectedly showed that the two side-arm p-tert-butylphenols of the original crown ether are converted to nitro p-tert-butylphenols in complex 2. In each complex the copper (II) ion is coordinated to two nitrogen and four oxygen atoms, two from the crown ether ring and other two from the deprotonated phenolate groups, which define an elongated octahedron. Electrochemical studies indicate that the two complexes undergo irreversible reduction in DMF solution. 相似文献
15.
Smith Gary L. N. Powell Douglas R. Moser Michelle D. Taylor Richard W. 《Journal of inclusion phenomena and macrocyclic chemistry》2022,102(5-6):515-521
Journal of Inclusion Phenomena and Macrocyclic Chemistry - The crystal structures are reported for 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-6,17-dione, (C12H22N2O6), (I),... 相似文献
16.
The electrochemical behaviour and cation recognition properties of two oxaferrocene cryptand ligands, 1,1′-[(1,4,10-trioxa-7,13-diazacyclopentadecane-7,13-diyl)diethoxy]-3,3′,4,4′-tetraphenylferrocene and 1,1′-[(1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diyl)diethoxy]-3,3′,4,4′-tetraphenylferrocene, have been characterized in acetonitrile in the presence of Ba2+ and Na+ by cyclic voltammetry, square wave voltammetry and a rotating disc electrode. The changes in the redox signals for the cryptates at varying concentrations of the target cations are used as a direct measure of the electronic coupling between the two units, leading to the conclusion that the cryptate formation process proceeds in multiple stages and the ligand offers several binding sites in the complex. 相似文献
17.
测定了双臂套索冠醚双核铜(Ⅰ)配合物[Cu2L(OH)](ClO4)3Me2CO(L=N,N'-二(8-喹啉甲基)-1,4,10,13-四氧-7,16-二氮环八环)的变温磁化率(4~300K),所加场强为5.O×105A/m.拟合了变温磁化率数据,得到J=-279.cm-1;加上分子场校正后,得J=-257.7cm-1,Zj'=-30.1cm-1.拟合结果表明,分子间存在反铁磁性交换作用,而分子内的磁交换(J<500cm-1)还未大到使其反铁磁性交换作用变为抗磁性.用自旋倾斜体系解释了其反常的χm-H图.晶体结构和Cu2+3d轨道的分析表明,磁交换作用是通过OH桥进行的.比较了另外2个类似的双核铜(Ⅰ)大环OH桥联配合物,得出了J值和轨道重叠之间的关系. 相似文献
18.
Paul F. Fore Jerald S. Bradshaw Steven F. Nielsen 《Journal of heterocyclic chemistry》1978,15(2):269-272
A new series of macrocyclic polyether-diesler compounds ( 3-12 ) have been prepared by treating various oligoethylene glyeols or mercaplans with oxalyl chloride. The compounds prepared were: 1,4,7,10,13-pentaoxacyclopentadecane-2,3-dione ( 3 ), 1,4,7,1 3-tetraoxa-10-thiacyclopenta-decane-2,3-dione ( 4 ), 1,4,10-lrioxa-7,13-dithiacyclopenladecane-2,3-dione ( 5 ), 1,4,7,10,13,16-hexaoxacyclooctadecane-2,3-dione ( 6 ), 1,4,7,10,13, 16-hexaoxacyclooctadecane-2,3,11,12-tetra-one ( 7 ), 1,4,10,13-tetraoxa-7,16-dithiacyclooctadecane-2,3,11,12-tetraone ( 8 ), 7,16-dioxa-1,4, 10,13-letralhiacyclooctadecane-2,3,11,12-tctraone ( 9 ), 1,4,7,10,13,16-hexathiacyclooctadecane-2,3,11,12-tetraone ( 10 ), 1,4,7,10,13,16,19-heptaoxacyclohencicosane-2,3-dione (11), and 1,4,7, 10,13,16,19,22-octaoxacyclolelracosane-2,3,14,15-letraone ( 12 ). 相似文献
19.
Teleb SM Gaballa AS Elmosallamy MA Nour el-M 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,61(11-12):2708-2712
The interaction of the mixed oxygen-nitrogen cyclic base, N,N'-dibenzyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (DD18C6) with pi-acceptors such as picric acid (HPA) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) has been studied spectrophotometrically in chloroform at 25 degrees C. The results obtained indicate the formation of 1:4 charge-transfer complexes with the general formula (DD18C6)(acceptor)4. The electronic and infrared spectra of charge-transfer complexes along with the (1)H NMR spectra were recorded and discussed. Based on the data obtained, the complexes were formulated as [(DD18C6H2)(HPA)2](PA)2 and [(DD18C6H2)(DDQ)2](DDQH)2. A general mechanism explaining the formation of the DDQ complex has been suggested. 相似文献
20.
Daniel Citterio Mio Omagari Shin-ichi Sasaki Yoshio Suzuki 《Analytica chimica acta》2004,504(2):227-234
This paper describes the design, synthesis, and the characterization of the two new chromogenic crown ethers 2,2′-[1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diylbis(methylene)]bis[4-[(1-methyl-4-(1H)-pyridinylidene)ethylidene]-2,5-cyclohexadien-1-one (KBC-001) and the lipophilic derivative 2,2′-[1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diylbis(methylene)]bis[4-[(1-dodecyl-4-(1H)-pyridinylidene)ethylidene]-2,5-cyclohexadien-1-one (KBC-002). A merocyanine dye that forms a betainic structure upon intramolecular charge transfer and shows solvent polarity dependent spectral sensitivity was selected as the chromophore system to develop the new chromoionophores. This approach allows the design of overall electrically neutral ligands bearing charged groups without the need of external counter ions. A proton ionizable group in the dye moiety acts as a charged ion-binding site and is an integral part of a lariat crown ether ionophore. A chromoionophore for calcium ion sensing has been developed, which combines the size-selective binding character of a crown ether with strong electrostatic attraction between the positively charged calcium ion and two negatively charged lariat side arms in the overall neutral compound. This water-soluble dye selectively responds to the presence of calcium ions in water at pH 8.5 with a dynamic response range between 10 μM and 10 mM. The binding event can be monitored both by absorption spectrometry and by fluorescence spectrometry. No cross-sensitivity was found for the physiologically important cations Mg2+, Li+, Na+, and K+ up to concentrations of 0.1 M under the same experimental conditions. In contrast to the water-soluble reagent KBC-001, the lipophilized derivative KBC-002 having two long alkyl chains was successfully applied to ion-exchange type optode membranes made from plasticized poly(vinyl chloride) (PVC). The dynamic response range of the optode at pH 9.0 was between 10 μM and 10 mM while retaining the high calcium selectivity. 相似文献