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1.
Ionic mobility in the NaSbClF3 · H2O, KSbClF3, and NH4SbClF3 fluorochloride complexes was studied by 1H and 19F NMR spectroscopy in the temperature interval from 150 to 480 K. The types of ionic motions in the compounds were determined. Their physicochemical characteristics were compared with those of the earlier studied sodium, potassium, and ammonium tetrafluoroantimonates(iii). The replacement of one F atom by the Cl atom in MSbF4 (M = Na, K, NH4) changes both the structure of the Sb polyhedra forming the structure of the antimony(iii) fluorochloride complex and the character of ionic motions in the compounds. The ionic conductivity in the 324–436 K range was determined for NH4SbClF3: σ = 1.07 · 10−4 S cm−1 at T = 423 K. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1353–1357, July, 2008.  相似文献   

2.
Crystalline substances formed in the (MF)1−x −(M′F) x −SbF3−H2O systems (M, M′=Na, K, Rb, Cs, and NH4;x=0 to 1) were investigated by121,123Sb NQR spectroscopy at 77 K. The formation of individual SbIII complexes NaCs3Sb4F16·H2O and NaKSbF5·1.5H2O, and statistically disordered mixed crystals M1−x −M′ x −SbF4 (M, M′=K, Rb, Cs, and NH4) was established. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 109–112, January, 1999.  相似文献   

3.
The mononuclear complexes (η3-terpy)M(Piv)2·MeCN (M = Fe ii (3) and Co ii (4), and Piv is the pivalate anion) were synthesized by the reactions of polymeric iron(ii) and cobalt(ii) pivalates with 2,2′:6′,2″-terpyridine (terpy). The oxidation of compound 3 affords the pentanuclear heterospin iron(ii,iii) complex (η3-terpy)Fe54-O)(μ3-OH)(μ-OH)2(μ-Piv)71-Piv)2 (5). All compounds were characterized by X-ray diffraction. Dedicated to the 90th anniversary of the L. Ya. Karpov Institute of Physical Chemistry. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1186–1190, June, 2008.  相似文献   

4.
A carbon paste electrode, modified with 2, 2′-[1,7-hepthandiylbis(nitriloethylidyne)]-bis-hydroquinone and TiO2 nanoparticles, was used for the simultaneous determination of dopamine (DA), uric acid (UA), and l-cysteine. The study was carried out by using cyclic voltammetry, chronoamperometry, and square wave voltammetry (SWV) techniques. Some kinetic parameters such as the electron transfer coefficient (α) and heterogeneous rate constant (ks) were also determined for the DA oxidation. A dynamic range of 8.0–1400 μM, with the detection limit of 8.4 × 10−7 M for DA, was obtained using SWV (pH = 7.0). The prepared electrode was successfully applied for the determination of DA, UA, and l-cysteine in real samples.  相似文献   

5.
New dinuclear ruthenium manganese complexes of general composition (bpy)2Ru(L)MnClx(H2O)2 (L is 1,10-phenanthroline-5,6-dione, 3,3′-dicarboxy-2,2′-bipyridyl, or bis(pyrazolyl); x = 2 or 4) were synthesized by the reaction of (bpy)2Ru(L) with MnCl2 · 4H2O. These compounds and the starting mononuclear ruthenium complexes were studied by spectrophotometric and electrochemical methods in MeCN. The position of the charge-transfer band RuII → L in the spectra depends on the donor-acceptor characteristics of the ligand L. For the dinuclear complex under study, the formal potentials of reversible one-electron oxidation of RuII are in the range of 0.9–1.2 V (vs. the standard hydrogen electrode), whereas oxidation of MnII occurs at more positive (by 0.1–0.2 V) potentials. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2281–2285, October, 2005.  相似文献   

6.
Dinuclear copper(II) complexes with acyldihydrazones of 2-hydroxy-5-nitroacetophenone (H4L) of the composition Cu2(Py)xmEtOH were synthesized and characterized. In these complexes, the coordination polyhedra of the copper atoms are linked to each other by a polymethylene chain of different lengths, from one to five monomer units. The structure of the [Cu2L·4Mrf] complex (Mrf is morpholine) based on acyldihydrazone of malonic acid was established by X-ray diffraction. The copper(II) atoms in this complex are [4+1]-coordinated and are spaced by 6.94 Å. At room temperature, the signal in the ESR spectra of solutions of the complexes based on acyldihydrazones of malonic, succinic, glutaric, and adipic acids has a seven-line hyperfine structure with the constant of (35.3–38.8)·10−4 cm−1 (g = 2.109–2.112) due to exchange interactions between unpaired electrons and two equivalent copper nuclei. An increase in the length of the polymethylene chain to five monomer units hinders exchange interactions, and the ESR signal of the complex based on acyldihydrazone of pimelic acid has a four-line hyperfine structure with a Cu = 72.7·10−4 cm−1 typical of mononuclear copper(II) complexes. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 229–234, February, 2007.  相似文献   

7.
Small additives of iron(II) or copper(II) salts change the regioselectivity of 2,4,6-trinitrotoluene monoreduction with titanium(III) chloride affording predominantly less accessible 2-amino-4,6-dinitrotoluene over 4-amino-2,6-dinitrotoluene (from 25% when the reduction occurs in the absence of the iron and copper salts to 70% in the presence of these salts). A possible mechanism of the process is discussed. Dedicated to Academician N. K. Kochetkov on the occasion of his 90th birthday. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1172–1176, May, 2005.  相似文献   

8.
The nature of intermediate species and their reactions were studied by laser pulse photolysis for a photochromic system consisting of 8,8′-diquinolyl disulfide (RSSR) and a planar NiII complex di(mercaptoquinolinato)nickel(II) (Ni(SR)2) in toluene and benzene solutions. Under exposure to laser radiation, disulfide RSSR dissociates to two RS· radicals, whose spectrum has an intense absorption band with a maximum at λ = 400 nm (ε = 8400 L mol−1 cm−1). The radicals disappear by recombination (2k rec = 4.6 · 109 L mol−1 s−1). In the presence of the Ni(SR)2 complex, coordination of the radical (k coord = 4.4 · 109 L mol−1 s−1) competes with recombination to form a radical complex RS· Ni(SR)2 having an intense absorption band with a maximum at 460 nm (ε = 16 600 L mol−1 cm−1). This species decays in the second-order reaction (2k = 4.6 · 104 L mol−1 s−1). Since the photochromic system returns to the initial state, the reaction of two radical complexes is assumed to produce radical recombination and reduction of the disulfide and Ni(SR)2 complex. Analysis of the kinetic data showed that some RS· radicals decay in the microsecond time interval due to the reaction with the RS· Ni(SR)2 radical complex (k = 3.1 · 109 L mol−1 s−1). Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2291–2300, October, 2005.  相似文献   

9.
A detailed investigation of sulphided Co/Mo/Al2O3 catalysts, their oxide precursors and several model oxides and sulphides of cobalt and molybdenum has been carried out using x-ray photoelectron spectroscopy and x-ray absorption spectroscopy (xanes andexafs). Octahedrally coordinated Co(II) and Mo(IV) are shown to be present in a sulphidic environment on the surfaces of these catalysts. The surface species contain an excess of sulphur, probably involving disulphide linkages. The surface compositions of the catalysts examined conform to the general formula Co11 Mo 2n IV (2n + 3)S 2 2− (2n -2)S2−.  相似文献   

10.
A kind of erbium hexacyanoferrate (ErHCF)-modified carbon ceramic electrodes (CCEs) fabricated by mechanically attaching ErHCF samples to the surface of CCEs derived from sol–gel technique was proposed. The resulting modified electrodes exhibit well-defined redox responses with the formal potential of +0.215 V [vs saturated calomel electrode (SCE)] at a scan rate of 20 mV s−1 in 0.5 M KCl (pH 7) solution. The voltammetric characteristics of the ErHCF-modified CCEs were investigated by voltammetry. Attractively, the ErHCF-modified CCEs presented good electrocatalytic activity with a marked decrease in the overvoltage about 400 mV for l-cysteine oxidation. The calibration plot for l-cysteine determination was linear at 5.0 × 10−6–1.3 × 10−4 M with a linear regression equation of I(A) = 0.558 + 0.148c (μM) (R 2 = 0.9989, n = 20), and the detection limit was 2 × 10−6 M (S/N = 3). At last, the ErHCF-modified CCEs were used for amperometric detection of l-cysteine in real samples.  相似文献   

11.
The reaction of 2,2′-di(2-hydroxybenzaliminoethyl) disulfide (H2L1) and 2-[(2-thioethyl)iminomethyl]phenol (H2L2) with MCl2·xH2O (M = Co, Ni, Cu) afforded the [M2(L1)Cl2] and [M(L2)]2 complexes, respectively. Their structures were determined by the data of electronic and IR spectroscopy and PM3 quantum chemical calculations. The H2L1 ligand and the complexes were studied by electrochemistry (CV and using a rotating disk electrode). The primary electronic changes are localized on the ligand fragment upon the electrochemical oxidation and reduction of the complexes. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1325–1330, July, 2007.  相似文献   

12.
The composition of complexes formed upon the extraction of UVI and ThIV nitrates with O-n-nonyl(N,N-dibutylcarbamoylmethyl) methyl phosphinate (L) from solutions of nitric acid without additional solvent was determined by 31P NMR spectroscopy. The structures of the complexes formed were studied by IR spectroscopy. Uranium(VI) is extracted from 3 and 5 M solutions of HNO3 as the [UO2(L)2(NO3)2] complex, while thorium(IV) is extracted from 5 M HNO3 as the [Th(L)3(NO3)3]+·NO 3 complex. In both cases, ligand L has bidentate coordination. Ligand L contacts with 3 and 5 M nitric acid to form adducts L·HNO3 and L· (HNO3)2, respectively. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2460–2464, November, 2005.  相似文献   

13.
A dependence between the quadrupole coupling constants (e 2 Qq zz ) and the asymmetry parameters of the electric field gradient (η) for the antimony atoms in the complex [SbF5]2− anions of M2SbF5 pentafluoroantimonites (M=Na, K, Rb, Cs, NH4, Ti, and Et2NH2) was revealed from the123Sb NQR spectra at 77 K. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1988–1990, October, 1998.  相似文献   

14.
An enzymatic method for determining L-malic acid in wine based on an L-malate sensing layer with nicotinamide adenine dinucleotide (NAD+), L-malate dehydrogenase (L-MDH) and diaphorase (DI), immobilized by sol-gel technology, was constructed and evaluated. The sol-gel glass was prepared with tetramethoxysilane (TMOS), water and HCl. L-MDH catalyzes the reaction between L-malate and NAD+, producing NADH, whose fluorescence (λ exc = 340 nm, λ em = 430 nm) could be directly related to the amount of L-malate. NADH is converted to NAD+ by applying hexacyanoferrate(III) as oxidant in the presence of DI. Some parameters affecting sol-gel encapsulation and the pH of the enzymatic reaction were studied. The sensing layer has a dynamic range of 0.1–1.0 g/L of L-malate and a long-term storage stability of 25 days. It exhibits acceptable reproducibility [s r(%)≈10] and allows six regenerations. The content of L-malic acid was determined for different types of wine, and polyvinylpolypyrrolidone (PVPP) was used as a bleaching agent with red wine. The results obtained for the wine samples using the sensing layer are comparable to those obtained from a reference method based on UV-vis molecular absorption spectrometry, if the matrix effect is corrected for.  相似文献   

15.
The enthalpies of dissolution of glycine (Gly) and L-α-alanine (Ala) in water at 288.15–318.15 K were measured. The results were compared with the earlier obtained data for L-α-phenylalanine (Phe) and L-α-histidine (His). The standard enthalpies of dissolution (Δsoln H 0) and differences (ΔC p 0 ) between the limiting partial molar heat capacity of the amino acids in solution and the heat capacity of the amino acids in the crystalline state were calculated in the temperature interval 273–373 K. Changes in the entropy of dissolution (ΔΔsoln S 0) and reduced Gibbs energy [Δ (Δsoln G 0/T)] in the temperature interval from 273 to 373 K were determined from the known thermodynamic relationships. The ΔC p 0 value is negative for hydrophilic glycine and positive for other amino acids. The ΔΔsoln S 0 values increase with an increase in the hydrophobicity of the amino acids. The Δ(Δsoln G 0/T) values become more negative in the order Ala, Phe, Gly, His. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 711–714, April, 2007.  相似文献   

16.
The synthesis, IR spectra, and the temperatures of the transition into a ferromagnetic state (T c) of layered ferromagnetics [R3RX[MCr(C2O4)3 (M = Mn, Fe, Co, Cu, and Ni) with the [Ph3BuP]+, [Bu3RN]+ (R = Pr, Et, and Me) cations capable of subsequently changing the distances between metallooxalate layers have been considered. The temperatureT c has been found to be independent of the size of the organic cation. It is believed that the determining factors in the transition to a ferromagnetic state are exchange interactions inside the metallooxalate layer.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2327–2330, September, 1996.  相似文献   

17.
The reactions of the Pd/ZrO2/SO4-catalyzed oxidation of ethylene, propene, and but-1-ene in a 0.1–1.5 M solution of perchloric acid with iron(III) aqua ions to carbonyl compounds, viz., acetaldehyde, acetone, and methyl ethyl ketone, respectively, were studied. The formation of palladium nanoparticles (5 nm) in solution on contact of the initial heterogeneous Pd/ZrO2/SO4 catalyst with perchloric acid was proved by transmission electron microscopy. The palladium nanoparticles are assumed to play the key role in olefin oxidation with the iron(III) aqua ions. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 627–632, April, 2006.  相似文献   

18.
The reaction of 5-[2-(methylthio)ethyl]-3-phenyl-2-thioxoimidazolidin-4-one (LH) with salts MCl2· xH2O (M = Co, Ni, Cu; x = 2, 6) afforded the [M(L)Cl]n complexes of NiII, CoII, and CuII. The electrochemical behavior of the LH ligand and its complexes was studied using the cyclic voltammetry and rotating disk electrode techniques. The structures of the synthesized compounds were determined by the data of UV—Vis and IR spectroscopy, mass spectrometry, and electrochemical characteristics. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 339–343, February, 2007.  相似文献   

19.
Phenylhydrazine reacts with thallium(iii) oxide in benzene to give organothallium compounds. Reactions of these compounds with acids afford diphenylthallium salts. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 857–858, April, 1997.  相似文献   

20.
Hypothetical mechanisms of oxidative carbonylation of alkynes to alkynoates in the PdCl2-CuCl2-base system are discusssed. σ-Alkynylcopper(i) and σ-alkynylpalladium(ii) complexes are considered to be the most probable intermediates in the process. A kinetic model of the reaction is proposed. The oxidative carbonylation of RC≡CCu in the PdCl2-CuCl2-base system leads to the formation of RC≡CCOOR'. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1806–1809, October, 1993.  相似文献   

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