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1.
A novel calix[4]arene derivative containing benzothiazole azo groups at the upper rim was synthesized as chromogenic chemosensor, and its binding and sensing properties with heavy metal ions (Pb2+, Hg2+, Ni2+, Cd2+, Cu2+, Zn2+, Co2+, Fe2+, Mn2+, Cr3+, Ag+) were investigated by UV-vis spectroscopy and voltammetric techniques. The results of spectroscopic and voltammetric experiments showed that the chromogenic chemosensor has high selectivity towards Hg2+ ion over the other heavy metal ions. Moreover, it was shown that the interaction between Hg2+ and the chromogenic chemosensor occurs by means of the benzothiazole azo groups at the upper rim by using differential pulse voltammetry. The stoichiometric ratio and the association constant were determined as 1:1 and (6.1 ± 0.3) × 105 L mol−1 for the complex between Hg2+ and the ionophore. Furthermore, we prepared a rapid test kit for early detection of Hg2+ in aqueous environment in the concentration range of 1 × 10−4 to 1 × 10−2 M.  相似文献   

2.
The synthesis and characterization of three novel Schiff bases of azocalix[4]arene and their selective copper extraction are described. The preparation of azocalix[4]arenes (1c, 2c and 3c) has been achieved by the condensation of 2-hydroxy-3-methoxybenzaldehyde with the amine group of upper rim mono-, di- and tetra-(aminophenylazo) calix[4]arene in ethanol. The synthesized products (1c, 2c and 3c) are characterized by both 1H and 13C NMR techniques, IR spectroscopy and elemental analysis. Extraction capabilities of interested derivatives of azocalix[4]arene from aqueous phase into organic phase are also examined. While extraction of Ag+, Hg+ and Hg2+ cations gave strong complexes with azo groups, extraction of Cu2+ cation is found to be highly effective with ?CCH=N?C and neighboring ?COH groups.  相似文献   

3.
A series of new calix[4]arene(amido)mono-crown compounds have been synthesized through aminolysis of calix[4]arene esters and intramolecular cyclization of the intermediates. The title compounds were converted into their nitro and azo substituted derivatives to provide novel photoresponsive molecular receptors for transition metal ions. Single crystal X-ray analysis of calix[4]arene(ethyleneamido)mono-crown (2a) revealed that the compound is present in a cone conformation with an amido loop that caps the lower rim of calix[4]arene cavity to result in stacking along axis a and axis c to provide supramolecular aggregates in the solid state. Evaluation of synthesized macrocycles in the solution phase for recognition of transition metal cations (Cr3+, Fe2+, Co2+, Ni2+, Cu2+, Ag+, Cd2+, Pb2+, Hg+, Hg2+, Pd2+, and Pt2+) by UV-visible spectroscopy revealed that p-tert-butyl-calix[4]arene mono-(amidocrown) 1c selectively shows a blue shift at 38 nm on interaction with Hg+ ions.  相似文献   

4.
Three novel chromogenic cone azocalix[4]arenes 5ac, which have cavity and the azo groups as metal-binding sites and as coloration sites were synthesized. They were studied by the liquid–liquid extraction of selected metal cations (Sr2+, Ag+, Hg+, Hg2+, Co2+, Ni2+, Cu2+, Zn2+, Cr3+, Al3+). Through examination of the extraction, a novel selectivity of these compounds toward Hg2+ cations has been determined. Besides, it has been also found that azocalix[4]arene 5c is highly sensitive to acid–base titration, which can be detected by the naked eye.  相似文献   

5.
Calix[4]arene based podands 1a of cone conformation and 1b of 1,3-alternate conformation possessing imine units and bearing anthracene moieties have been synthesized by a 1 + 2 Schiff base condensation in good yields and examined for their cation recognition abilities towards cations such as lithium, sodium, potassium, nickel, cadmium, copper, zinc, lead, silver and mercury ions by UV–vis and fluorescence spectroscopy. The calix[4]arene derivative 1b shows a selective fluorescence enhancement in presence of Cu2+ ions among the various metal ions tested (Li+, Na+, K+, Ni2+, Cd2+, Cu2+, Zn2+, Pb2+, Ag+ and Hg2+ ions). The colour of the solution changes from colourless to light yellow in the presence of Cu2+ ions. The stoichiometry of the complex formed between 1b and Cu2+ was found to be 1:1 as established by Job’s plot.  相似文献   

6.
A new pyrene derivative (1) containing a diaminomaleonitrile moiety exhibits high selectivity for Cu2+ detection. Significant fluorescence enhancement was observed with chemosensor 1 in the presence of Cu2+. However, the metal ions Ag+, Ca2+, Cd2+, Co2+, Fe2+, Fe3+, Hg2+, Mg2+, Mn2+, Ni2+, Pb2+, and Zn2+ produced only minor changes in fluorescence values for the system. The apparent association constant (Ka) of Cu2+ binding in chemosensor 1 was found to be 5.55×103 M−1. The maximum fluorescence enhancement caused by Cu2+ binding in chemosensor 1 was observed over the pH range 5-7.5.  相似文献   

7.
Effects of chlorides of univalent (LiCl, NaCl, KCl), bivalent (MgCl2, BaCl2) and trivalent (AlCl3) metals at different concentration (0.001–0.1 M) on the behavior of nanosilica A-200 (0.5–5 wt.%) in aqueous media are analyzed using photon correlation spectroscopy (particle size distribution, PSD), electrophoresis (zeta potential ζ), potentiometric titration (surface charge density), and estimation of screening length of primary particles and their aggregates. The zeta potential and the PSD are affected by silica content, pH, and concentration and type of dissolved salts. Smaller but more strongly hydrated Li+ cations caused stronger nonlinear dependences of the zeta potential on pH and salt content than Na+ or K+. This nonlinearity is much stronger at a lower content of silica (0.5–1 wt.%) than at C A-200 = 2.5 or 5 wt.%. At a high concentration of nanosilica (5 wt.%) the effect of K+ ions causes stronger diminution of the negative value of the zeta potential due to better adsorption of larger cations. Therefore, the influence of K+ on increasing screening length is stronger than that of Na+ for both primary nanoparticles and their aggregates. A similar difference in the ζ values is observed for different in size cations Ba2+ and Mg2+.   相似文献   

8.
Calix[4]arene 3, which contains two distal triazole groups on the lower rim and two distal o-methoxyphenylazo groups on the upper rim, was synthesized and found to be a specific and ratiometric sensor for Hg2+ in a polar protic solvent. A series of o-methoxyphenylazo derivatives (3, 4, 5, 7, and 9) were synthesized, which proved that the lower-rim triazoles and the hydroxyl azophenol(s) were the major ligands for metal ion binding. Though analogues 4 and 10 showed some sensitivity for Hg2+, compound 3 was the only ratiometric chemosensor for Hg2+ among the series of azocalix[4]arenes synthesized in this work. The formation of 3·Hg2+ complex was supported by UV/vis and NMR titration studies and Mass spectrometry. Based on the symmetrical features of NMR spectra of 3·Hg2+, the complex is believed to be symmetrical with respect to the calix[4]arene cavity. Furthermore, the complex was determined to be 1:1 binding stoichiometry by Job’s plot, and the association constant was determined to be 4.02×103 M−1 using Benesi-Hildebrand plot.  相似文献   

9.
Three series of heterocycle substituted calixarenes, derivatized at lower and upper rim, were synthesized and successfully evaluated for metal extraction towards alkali, alkaline, transition and heavy metal ions. The presence and placement of sulfur, heterocycle functionality at upper/lower rim played a crucial role toward the extractability and selectivity of metal ions. The lower rim substituted calixarenes have shown high extractability and poor selectivity. In contrast to this, upper rim substituted calixarenes exhibited good selectivity. Moreover, sulfur functionalized calixarenes have shown better selectivity for heavy metal ions than alkali and alkaline metal ions. Among upper rim substituted calixarenes, 17 and 18 were found to be suitable for Na+, K+ and Ag+, 19,13 for heavy metal ions i.e., Pb2+, Hg+, Hg2+ and Ag+, and 11,12 for Pb2+ and Ag+ only.  相似文献   

10.
From extraction experiments and $ \gamma $ -activity measurements, the exchange extraction constants corresponding to the general equilibrium M2+(aq) + Sr2+(nb) $ \Leftrightarrow $ M2+(nb) + Sr2+(aq) taking place in the two-phase water–nitrobenzene system (M2+ = Mg2+, Ca2+, Ba2+, Pb2+, Cu2+, Zn2+, Cd2+, $ {\hbox{UO}}_{2}^{2 + } $ , Mn2+, Co2+, Ni2+; 1 = macrocyclic lactam receptor–see Scheme 1; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Moreover, the stability constants of the M2+ complexes in nitrobenzene saturated with water were calculated; they were found to increase in the following cation order: Mg2+ < Co2+ < Cu2+, Mn2+, Ni2+ < Cd2+ < Ca2+ < Ba2+, Zn2+ < Pb2+ <  $ {\hbox{UO}}_{2}^{2 + } $ .
Scheme 1
Structural formula of 2,18-dichloro-9,10,11,12-tetrahydro-6H, 20H-dibenzo[l,o][1,11,4,8]dioxadiazacyclohexadecine-7,13(8H, 14H)-dione (abbrev. 1)  相似文献   

11.
New fluorescent chemosensor 1 with two amidoanthraquinone groups (1-AAQs) at the lower rim of p-tert-butylcalix[4]arene has been synthesized. The significant changes of absorption and fluorescence bands show that chemosensor 1 is selective toward fluoride ion (F) over other anions such as Cl, Br, I, CH3COO, , , and OH. The ESIPT process of 1 is inhibited by the fluoride-induced H-bonding followed by deprotonation of NH of the 1-AAQ.  相似文献   

12.
The influence of Li+, Na+, K+, Rb+, Cs+, Mg2+, Ca2+, Sr2+, Ba2+, Ag+, Cd2+, Co2+, Fe2+, Hg2+, Mn2+, Pb2+, Zn2+ and Fe3+ on the spectroscopic properties of two dansyl (1-dimethylaminonaphthalene-5-sulfonyl) groups linked to the lower rims of a series of three, structurally related, di-ionized calix[4]arenes is investigated by means of absorption and emission spectrophotometry. Di(tetramethylammonium) salts of the di-ionized ligands, L, L1, and L2, which differ in having no, two and four allyl groups, respectively, on the upper rim of the calix[4]arene scaffold, are utilized for the spectrofluorimetric titration experiments in MeCN. On complexation by alkaline earth metal cations, the emission spectra undergo marked red shifts and quenching of the dansyl fluorescence. These effects are weaker with alkali metal cations. Transition metal cations and Pb2+ interact strongly with the ligands. In particular, Fe3+, Hg2+ and Pb2+ cause greater than 99% quenching of the dansyl fluorescence.  相似文献   

13.
Aasif Helal 《Tetrahedron》2010,66(52):9925-9932
A new thiazole sulfonamide (TTP, 1) based Zn2+ selective intrinsic chemosensor has been synthesized and investigated. The chemosensor shows a selective fluorescence enhancement (3.0 fold) with Zn2+ over biologically relevant cations (Ca2+, Mg2+, Na+, and K+) and biologically non-relevant cations (Cd2+) in an aqueous ethanol system. It produces an increase in the quantum yield and a longer emission wavelength shift (64 nm) on Zn2+ binding with the potential of a ratiometric assay.  相似文献   

14.
This article displays the synthesis of N-(2-tosylato)ethylpiperazine (ii) and 5,11,17,23-tetra-tert-butyl-25,27-bis-(2-piprazinoethyl)-26,28-dihydroxycalix[4]arene (3). Compounds (ii) and 3 were characterized through elemental analysis, FT-IR, 1H NMR and/or 13C NMR studies. The transition metal cations (Hg2+, Co2+, Ni2+, Cu2+, and Cd2+) and dichromate anion were studied by liquid–liquid extraction experiment. The results showed that compound 3 has moderate but selective extraction ability for Hg2+ and dichromate anion. Comparison between extraction properties of compound 3 with previously reported 5,11,17,23-tetra-tert-butyl-25,27-bis(isoniazidylcarbonylmethoxy)-26,28-dihydroxy-calix[4]arene (4) and protonated pyridinium form of 4 (5) is also described.  相似文献   

15.
By applying an indirect strategy, a new copper (Ⅱ) complex of a thiosemicarbazone L has been successfully developed as a colorimetric chemosensor for the sensitive detection of mercury (Ⅱ) ions. In the presence of copper (Ⅱ) ions, the colorless solution of L became yellow; however, upon the addition of traces of mercury (Ⅱ) ions, the yellow color faded to colorless immediately. Other ions, including Fe3+ , Ag+ , Ca2+ , Zn2+ , Pb2+ , Cd2+ , Ni2+ , Co2+ , Cr3+ and Mg2+ had a negligible influence on the probe behavior. The detection limits were 5.0×10 -6 M and 3.0×10 -7 M of Hg2+ using the visual color changes and UV-vis changes respectively. Test strips based on Cu-L were fabricated, which could act as a convenient and efficient Hg2+ test kits.  相似文献   

16.
Anthracene anchored 1,3-di-derivatives of lower rim p-tert-butyl-calix[4]arene were synthesized and characterized. These derivatives were subjected to the binding studies with the divalent metal ions, viz., Mg2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+ and Zn2+ using fluorescence and absorption spectra. The imine moiety that is in conjugation with the anthryl unit is responsible for quenching the fluorescence in the absence of metal ion, however, in the presence of Fe2+ and Cu2+, the spectra showed very high enhancement in fluorescence intensity indicating that the lone pair present on the imine-N is involved in the metal ion binding and as a result the photo-induced electron transfer is prevented. Based on the photo-physical studies, it has been found that the anthracene derivative that is coupled with the calix[4]arene unit through an imine bond acts as a chemosensor for Fe2+ and Cu2+. The fluorescence studies are further augmented by the absorption spectra.  相似文献   

17.
The bis-{N-(2-hydroxynaphthyl-1-methylimine)} anchored 1,3-di-derivative of lower rim p-tert-butyl-calix[4]arene possessing a N2O2, N2O4 or N2O6 binding core was found to be selective for Zn(II) ions even at ?60 ppb by eliciting fluorescence-on behaviour while the other ions, viz., Ti4+, VO2+, Cr3+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Mg2+, Cd2+ and Hg2+ caused no change in the fluorescence. The reaction between 1 and Zn2+ was found to be stoichiometric with the formation of a 1:1 complex; while H+ quenched the fluorescence of the complex, OH restored it. The studies of the 1:1 isolated complexes of Zn2+, Ni2+ and Cu2+ augmented the results.  相似文献   

18.
Kinetics, activation parameters, and the kinetic isotope effect (KIE) of hydrogen have been determined for the first rate-limiting step of the reactions of benzene, monoalkylbenzenes, dimethylbenzenes, and trimethylbenzenes in HVO3-sulfuric acid (54–70 wt % H2SO4) solutions. The effects of solution acidity on the rate constants (k) and KIE have been studied. The reactions begin with electron transfer from the arene to VO 2 + and end with oxidative coupling: $PhCH_3 \xrightarrow{{VO_2^ + }}PhCH_3^{ + \cdot } \xrightarrow{{ - H^ \cdot }}PhCH_2^ + \xrightarrow{{PhCH_3 }}PhCH_2 C_6 H_4 CH_3 .$ logk is a linear function of the ionization potential of the arene (I ArH). A three-parameter correlation is for the first time established between the activation energy (E), the logarithm of the preexponential factor (log A), and I ArH: logA = 0.15E ? 0.058I ArH + 49.1 (E and I ArH are expressed in kJ/mol). The reactions of arenes with VO 2 + , NO 2 + , and Co3+ are intercompared.  相似文献   

19.
Cluster ions of alloys (Li-Na, Li-Mg) have been produced by a liquid metal ion source (LMIS), and analyzed by mass spectrometry. For the Li-Na system, bimetallic clusters with various compositions were formed, and dominant bimetallic species were Na2Li+, NaLi+, NaLi 2 + and NaLi 8 + with this sequence of ion intensity. These clusters are systems containing 2 or 8 valence electrons except for NaLi+. For the Li-Mg, observed bimetallic clusters were limited to only three species (MgLi+, MgLi 2 + and Mg2Li+), but unexpectedly small multiply charged homonuclear clusters, Mg 2 2+ and Mg 3 2+ , were observed.  相似文献   

20.
N-Tosyl-2,6-diisopropyl-4-(2,3-dimethoxylbenzoylamide)aniline (1) has been synthesized and its metal ion (Na+, K+, Ca2+, Mg2+) coordinating properties investigated by FT-IR, ESI-MS, and 1H NMR methods. Among the tested metal ions, the overall stability constant (log K) for Mg2+ (6.89) is the highest (Na+, 5.64; K+, 5.43; Ca2+, 5.51) in 10% water/THF at 25.0 ± 0.5 °C determined by UV-vis spectroscopy, indicating that 1 is a potent ionophore for Mg2+ ion.  相似文献   

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