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1.
V. L. Lobachev G. P. Zimtseva E. S. Rudakov Yu. V. Geletii 《Theoretical and Experimental Chemistry》2000,36(1):42-47
The first observed basic products of the reaction of dimethylsulfoxide with peroxonitrite were methyl nitrite and methane
with pH=7 and methyl nitrate at pH>10. The dependence of the yield of these and other reaction products on pH, concentrations
of the substrate and peroxonitrite, and the additives NO
2
−
and CO2 was studied. It is proposed that CH4 and CH3ONO are formed in the reaction between DMSO and the cis-form of−OONO, while DMSO2 and CH3ONO2 are formed in reactions with the trans-form of−OONO or the dimer HOONO/OONO respectively.
Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 36, No. 1, pp. 41–46, Jaunuary–February, 2000. 相似文献
2.
Ibrahim M. EI-Mehasseb Abd El-Motaleb M. Ramadan Raafat M. Issa 《Transition Metal Chemistry》2006,31(6):730-739
The oxidation of catechol by molecular oxygen in the presence of a catalytic amount of copper(II) complex with 2-methyl-3-amino-(3H)quinazoline-4-one (MAQ) and various anions (Cl−, Br−, ClO
4
−
, SCN−, NO
3
−
and SO
4
–
) was studied. The catecholase biomimetic catalytic activity of the copper(II) complexes has been determined spectrophotometrically
by monitoring the oxidative transformation of catechol to the corresponding light absorbing o-quinone (Q). The rate of the catalytic oxidation reaction was investigated and correlated with the catalyst structure, time,
concentration of catalyst and substrate and finally solvent effects. Addition of pyridine or Et3N showed a dramatic effect on the rate of oxidation reaction. Kinetic investigations demonstrate that the rate of oxidation
reaction has a first order dependence with respect to the catalyst and catechol concentration and obeying Michaelis–Menten
Kinetics. It was shown that the catalytic activity depends on the coordination environment of the catalyst created by the
nature of counter anions bound to copper(II) ion in the complex molecule and follows the order: Cl− > NO
3
−
> Br− > SO
4
–
> SCN− > ClO
4
−
. To further elucidate the catalytic activity of the complexes, their electrochemical properties were investigated and the
catecholase mimetic activity has been correlated with the redox potential of the Cu2+/Cu+ couple in the complexes. 相似文献
3.
Gamma — radiolytic decomposition of sodium and potassium nitrates and its admixtures with respective cyanide and borate additives
has been studied over a wide absorbed dose range from 675 to 500 kGy. The decomposition of nitrate increases with the nature
and concentration of the additive in the admixture. The enhancement is more significant at >80 mol% of the additive.G(NO
2
−
) values, calculated on the basis of electron fraction of the nitrate salt, decrease with increasing concentration of the
nitrate. ESR spectral studies suggest the formation of radical species such as BO4 and BO
3
2−
etc, in borates whereas in case of cyanide additive FH centres are produced. The radical species and colour centres so produced may then transfer their energy to nitrate and cause
enhancement in decomposition. A comparison with other oxyanion additives shows thatG(NO
2
−
) values decrease in the order PO
4
3−
>B4O
7
2−
>SO
4
2−
>CO
3
2−
. Similarly, the nature of the cation also affects the decomposition. 相似文献
4.
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
5.
The rate of reaction of NO
2
−
ion with various FeIII porphyrins in the presence of PPh3 is shown to depend on the redox potential of the FeIII center. There is a linear relationship between the ease of reduction of the FeIII to FeII and the kinetics for the formation of the FeII porphyrin nitrosyl adduct, with concomitant oxidation of PPh3 to PPh3O. Cyclic voltammograms show reversible one-electron reductions that can be ascribed to the FeIII/FeII couple ranging from E1/2 = −343 to −145 mV (versus Ag/AgCl). The order of increasing half-wave reduction potentials for the FeIII/FeII porphyrin redox centers studied is octaethylporphyrin > etioporphyrin I > deuteroporphyrin IX dimethyl ester > protoporphyrin
IX dimethyl ester > α,β,γ,δ-tetraphenylporphyrin. This sequence of redox potentials complements the pseudo first-order kinetics
(
to
m s
−1) for the oxidation of PPh3 and subsequent FeII porphyrin nitrosyl adduct formation. The rates of reaction of biomimetic FeIII porphyrins with NO
2
−
ion demonstrate how metal center redox properties are influenced by the surrounding ligand. In this paper we have elucidated
a possible mechanistic control for the rate of this reaction. 相似文献
6.
Shamim A. Chaudhri R. Ahmed M. Ejaz 《Journal of Radioanalytical and Nuclear Chemistry》1977,35(2):235-243
The extraction of HCl, HBr, HNO3, HClO4, H2SO4 and CH3COOH into solutions of 4-(5-nonyl)pyridine (NPy) and 2-hexylpyridine (HPy) dissolved in benzene has been studied. The results
show that the larger, less basic anions extract better (ClO
4
−
>CH3COO−≥NO
3
−
>Br−>Cl−>HSO
4
−
) due to their low aqueous hydration. The ionization constants of NPyH+ and HPyH+ as determined spectrophotometrically were found to be 5.97±0.06 and 5.94±0.05, respectively, at 25°C. 相似文献
7.
Enrichment of51Cr has been made by recoil enrichment using potassium chromate as the target material. Irradiation of four days at a neutron
flux of 2·1013n·cm−2·sec−1 in the core of PARR, followed by a chemical separation using a new liquid-anion exchanger, diphenyl-2pyridylmethane (0.1M
in chloroform) gives a product of high specific activity (>30 Ci per gram), suitable for medical diagnostic applications. 相似文献
8.
Simultaneous determination of silicic acid, Ca, Mg and Al in mineral water and composite tablets by Ion chromatography 总被引:1,自引:0,他引:1
Q. Xu C. Xu W. Zhang Y. P. Wang L. T. Jin H. Haraguchi A. Itoh K. Tanaka 《Chromatographia》2001,53(1-2):81-84
Summary A simple, selective and sensitive ion-chromatography method was investigated for simultaneously determining silicic acid,
Ca2+, Mg2+, Al3+ and anions (Cl− and NO
3
−
) in real samples. It involved a single-column ion-chromatograph with sodium hydroxide-methanol-water eluent and conductometric
detection. Cations were converted to complex anions by adding EDTA to the sample solution. A set of well-defined peaks of
silicic acid, Ca2+, Mg2+, Al3+, Cl− and NO
3
−
were obtained. Detection limits using 3.3σ (σ=standard deviation of blank solution) were 1.25×10−6 M for H3SiO
4
−
, 1.32×10−6 M for Ca2+, 1.28×10−6 M for Mg2+, 1.33×10−6 M for Al3+, 1.31×10−6 M for Cl− and 1.24×10−6 M for NO
3
−
. The method was successfully applied to analysis of mineral water and composite tablets. 相似文献
9.
CO activation in the [Ru(NH3)5CO]2+ ion has been demonstrated under nucleophilic conditions in pyridine or 2-ethoxyethanol solution at 100 °C. In the presence
of Me3NO the observed pseudo-first order rate constants were found to be sensitive only to auxiliary ligand concentration (pyridine
or methyl pyridines), but with a tendency towards rate saturation and the same limiting rate at large excess of each entering
ligand. A mechanism is proposed in which the rate-limiting step is viewed as an auxiliary ligand-assisted CO2 elimination, preceded by a fast reversible addition of Me3NO. This reaction pathway is also supported by the values determined for ΔH
‡ (81 ± 13 kJ mol−1) and ΔS
‡ (−114 ± 36 J mol−1 K−1).
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
10.
G. R. Dey 《Research on Chemical Intermediates》2007,33(7):599-611
Gamma radiolysis of oxygenated 1–10 mM azide solutions was carried out at various pH values. In oxygenated 10 mM azide solutions,
H2O2 and NO
2
−
were observed as radiolytic products while NH3 was not. The concentration of H2O2 reached its maximum level at a dose of 1 kGy, whereas NO
2
−
yield increased non-linearly beyond 2 kGy in this system. Both in aerated and oxygenated systems, G(NO
2
−
) and G(H2O2) were found to vary with N
3
−
concentration. The yield of NO
2
−
was found to be dependent on both dose rate and pH. On pulse radiolysis, NO
2
−
was found as a radiolytic product in aerated 1 mM azide solution at pH 6.8. In this system the intermediate generated exhibits
absorbance around 250 nm. The overall results obtained during the present study reveal that in presence of both reducing radical
(mainly e
aq
−
) and oxygen, N
3
−
produced an intermediate possibly NH2O
2
•
radical, which is the prime source for NO
2
−
generation. 相似文献
11.
A flow injection method is described for the determination of iron in fresh water based on potassium permanganate chemiluminescence
detection via oxidation of formaldehyde in aqueous hydrochloric acid. Total iron concentrations are determined after reducing
Fe(III) to Fe(II) using hydroxylamine hydrochloride. The detection limit (three standard deviations of blank) is 1.0 nM, with
a sample throughput of 120 h−1. The calibration graph was linear over the range (2–10) × 10−7 M (r
2 = 0.9985) with relative standard deviations (n = 5) in the range 1.0–2.3%. The effect of interfering cations (Ca(II), Mg(II), Zn(II), Ni(II), Co(II), Fe(III), Mn(II), Pb(II),
and Cu(II)) and common anions (Cl−, SO
4
2−
, PO
4
3−
, NO
3
−
, NO
2
−
, I−, F−, and SO
3
2−
) was studied at their maximum admissible concentrations in fresh water. The method was applied to fresh-water samples from
the Quetta Valley, and the results obtained (0.04 ± 0.001–0.11 ± 0.01 mg/L Fe(II)) were in reasonable agreement with those
obtained using the spectrophotometric reference method (0.05 ± 0.01–0.12 ± 0.02 mg/L Fe(II)).
The text was submitted by the authors in English. 相似文献
12.
Chi Won Kim Jungmin Ahn Sung Min Kim Tae Hwan Noh Ok-Sang Jung 《Transition Metal Chemistry》2011,36(5):545-551
Type studies on competitive polyatomic anion versus acetonitrile coordination in the self-assembly of a series of [Ag2(X)
m
(bip)(NCCH3)
n
](X)2−m
(X− = NO3
−, CF3SO3
−, ClO4
−, BF4
−, and PF6
−; m = 0, 2; n = 0, 2, 4; bip = 1,4-bis(2-isonicotinoyloxyethyl)piperazine) were carried out. Each bip spacer acts as an N4 tetradentate ligand and is linked to four silver(I) centers through two pyridine and two piperazine moieties, producing a
double strand consisting of two 20-membered ring units. The coordinating environment around the silver(I) center is subtly
determined by the competition of the polyatomic anions with acetonitrile, that is, by the Ag···NCCH3 versus Ag···X interactions. The coordinating ability of acetonitrile is inversely proportional to the order of the coordination
ability of the Hoffmeister series of polyatomic anions, NO3
− ≫ CF3SO3
− > ClO4
− > BF4
− ≫ PF6
−. 相似文献
13.
The adsorption and activation of NO molecules on Cu-ZSM-5 catalysts with different Cu/Al and Si/Al ratios (from 0.05 to 1.4 and from 17 to 45, respectively) subjected to different pretreatment was studied by ultraviolet-visible diffuse reflectance (UV-Vis DR). It was found that the amount of chemisorbed NO and the catalyst activity in NO decomposition increased with an increase in the Cu/Al ratio to 0.35–0.40. The intensity of absorption bands at 18400 and 25600 cm−1 in the UV-Vis DR spectra increased symbatically. It was hypothesized that the adsorption of NO occurs at Cu+ ions localized in chain copper oxide structures with the formation of mono- and dinitrosyl Cu(I) complexes, and this process is accompanied by the Cu2+...Cu+ intervalence transfer band in the region of 18400 cm−1. The low-temperature activation of NO occurs through the conversion of the dinitrosyl Cu(I) complex into the π-radical anion (N2O2)− stabilized at the Cu2+ ion of the chain structure, [Cu2+-cis-(N2O2)−], by electron transfer from the Cu+ ion to the cis dimer (NO)2. This complex corresponds to the L → M charge transfer band in the region of 25600 cm−1. The subsequent destruction of the complex [Cu2+-cis-(N2O2)−] at temperatures of 150–300°C leads to the release of N2O and the formation of the complex [Cu2+O−], which further participates in the formation of the nitrite-nitrate complexes [Cu2+(NO2)−], [Cu2+(NO)(NO2)−], and [Cu2+(NO3)−] and NO decomposition products. 相似文献
14.
The effect of the concentration of water on the rate of reduction of molecular nitrogen to hydrazine by niobium(iii) hydroxide in alkaline H2O−MeOH and D2O−MeOD mixtures was studied. In both cases, the reaction rate is maximum when [H2O]=4 mol L−1, and the inverse isotopic effect (K
D/k
H>1) is observed when [H2O]<20 mol L−1. Similar regularity was observed for the reaction of hydrogen elimination. It was found that HD is formed in the H2O−MeOH system in the presence of D2. The conclusion was made that the ratedetermining stage in hydrazine formation is the transfer of a hydride ion to the dinitrogen
molecule coordinated to the binuclear NbIII center. A kinetic scheme satisfactorily explaining the effect of the concentration of water ([H2O]=1.5−49.0 mol L−1) on the reaction rate constant was proposed.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1600–1604, September, 1997. 相似文献
15.
The adsorption of NO, NO/O2 mixtures and NO2 on pure ZrO2 and on two series of catalysts supported on ZrO2, one containing vanadia and the other molybdena (ZV and ZMo, respectively), has been investigated. The V and Mo surface contents
of the latter were ≤3 atoms nm−2 and ≤5 atoms nm−2, respectively. All samples had been previously submitted to a standard oxidation treatment.
On all samples, only extremely minor amounts of NOx surface species are formed by NO interaction at room temperature (RT). NOx surface species are formed in greater amounts on pure ZrO2 when NO and O2 are coadsorbed at RT; they are mainly nitrites, small amounts of nitrates, and small amounts of (O2NO−H)δ− species; when ZrO2 is warmed to 623 K in the NO/O2 mixture, nitrites decrease, nitrates and (O2NO−H)δ− species increase. The same NOx species as on the ZrO2 surface free from V (or Mo) are formed on ZV (or ZMo) samples with surface V (or Mo) density <1.5 atoms nm−2; however, they occur in decreased amount with increasing V (or Mo) coverage. On ZV samples with a surface V density of 1.5–3
atoms nm−2 (or ZMo samples with a surface Mo density of 1.5–5 atoms nm−2) when NO and O2 are coadsorbed at RT, there is formation of small amounts of nitrites, nitrates (both on ZrO2 surface free from V (or Mo) and at the edges of V- or Mo-polyoxoanions) and NO2
δ+ species, associated with V5+ (or Mo6+) of very strong Lewis acidity; when samples are warmed up 623 K in the NO/O2 mixture, nitrites disappear, nitrates increase, NO2
δ+ species remain constant or slightly decrease. When NO2 is allowed into contact at RT with oxidized samples, surface situations almost identical to those obtained for each sample
warmed to 623 K in NO/O2 mixture is reached. The NOx surface species stable at 623 K, the temperature at which catalysts show the best performance in the selective catalytic
reduction (SCR) of NO by NH3, are nitrates, both on ZrO2 and on polyvanadates or polymolybdates at high nuclearity. On the contrary, nitrites and NO2
δ+ species are unstable at 623 K. 相似文献
16.
N. A. Sanina N. S. Emel’yanova A. N. Chekhlov A. F. Shestakov I. V. Sulimenkov S. M. Aldoshin 《Russian Chemical Bulletin》2010,59(6):1126-1136
Dinuclear iron tetranitrosyl complex with the composition [Fe2(SPh)2(NO)4] (1) was synthesized and its single crystals and polycrystals were studied by X-ray diffraction, IR spectroscopy, and elemental
analysis. The decomposition products of complex 1 were investigated by electrochemical method and mass spectrometry. The mass spectrum of a solution of complex 1 shows two groups of ions: the primary decomposition products of 1 in solution (the complex ions [Fe(SPh)(NO)2(NO2)]−, [Fe(SPh)2(NO)]−, and [Fe(SPh)2(NO)2]−) and a series of the ions [FeO2 + n(NO)]− and [FeO3 + n(NO)]− (n = 0–4), which are formed in secondary reactions. The structures of the complexes, which were formed through the Fe-NO bond
dissociation and the replacement of the NO ligand by aqua and oxygen ligands in complex 1, and the structure of the complex [FeO3]− were studied by quantum chemical modeling. 相似文献
17.
Abstract
The electronic structure of Hg(II) ions, [Hg(L) n (H2O) m ] q (L = HO−, Cl−, HS−, S2−) has been studied. Geometries were fully optimized. The B3LYP and PBE functionals give structures in good agreement with available experimental data. Calculated stretching frequencies generally correlate well with bond lengths. The role of the water molecule(s) in the solvated Hg(II) complexes has been investigated. The solvent can act as nucleophile, as hydrogen bond acceptor or as a spectator. The trans-effect results in lengthening of the Hg–L bond length. It can be understood as a competition between ligands in trans positions for the ability to donate their electron density to the 6s AO of Hg(II). The effect of the presence of water molecules on the Hg–L bond length depends on whether or not the water molecules form a direct coordination bond with Hg(II); it will not guarantee an increase in the stability of the complexes. The interaction energy, which represents the interaction between Hg(II) and ligand L and excludes all other interactions, is nucleophilicity-dependent. The interaction energy and the strength of the ligand nucleophilicity follow the order: S2− > HS− > HO− > Cl− > H2O. The charge transfer, ΔN, is an indication for the type and strength of the interaction between ligand and Hg(II). Increasing the positive and negative value of ΔN will decrease and increase the Hg(II) total NBO charge, respectively, while decreasing the electrophilicity of Hg(II) will decrease its charge and the charge transfer, ΔN. 相似文献18.
Huang KJ Zhang M Xie WZ Zhang HS Feng YQ Wang H 《Analytical and bioanalytical chemistry》2007,388(4):939-946
A simple, sensitive, selective, and low-cost method is proposed for rapidly determining nitric oxide (NO) in some rat tissues.
Polymer monolith microextraction (PMME) using a poly(methacrylic acid–ethylene glycol dimethacrylate) (MAA-EGDMA) monolithic
column was combined with derivatization of NO using 1,3,5,7-tetramethyl-8-(3′,4′-diaminophenyl)-difluoroboradiaza-s-indacene (TMDABODIPY), and this was used to analyze the derivatives of NO by high-performance liquid chromatography (HPLC)
with fluorescence detection at λ
ex/λ
em = 498/507 nm. The baseline separation of TMDABODIPY and its NO derivative is performed under simple conditions in which a
C18 column is used and eluted with 50 mmol L−1 ethanolamine and methanol. The conditions for the extraction of NO derivatives were optimized. The limit of detection of
NO was 2 × 10−12 mol L−1 (S/N = 3). The linearity range of the method was 9 × 10−11−4.5 × 10−8 mol L−1. The interday and intraday relative standard deviations were less than 5%. The proposed method was successfully applied to
the determination of NO levels in some rat tissue samples including heart, kidney, and liver with recoveries varying from
87.1 to 95.2%. 相似文献
19.
A. Yu. Timoshkin 《Russian Journal of Inorganic Chemistry》2009,54(1):86-99
The structural and thermodynamic properties of oligomeric anions [M
n
X3n+ 1]− (M = Al, Ga, In; X = F, Cl, Br, I; n = 2, 3, 4) have been obtained by the density functional theory B3LYP method with the LAN2DZ(d) and LAN2DZ(d)+ basis sets.
A wide diversity of structural isomers was found for trimeric fluoride anions M3F10−. Among the trimers, except In3F10−, the most stable is a linear isomer composed of two MX3 molecules coordinated to the MX4− anion. The formation of tetrameric anions M4X13− was demonstrated to be thermodynamically allowed at low temperatures at MX3: X− > 4: 1. The existence of higher oligomers is less probable. The affinity of oligomer halides (MX3)
n
for halide ions increases with an increase in n. The propensity to form oligomeric anions decreases in the series F > Cl ≥ Br > I. The fluoride systems show a tendency to
form structures with CN = 5 and 6, these structures for In being the most stable.
Original Russian Text ? A.Yu. Timoshkin, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 1, pp. 87–100. 相似文献
20.
N. A. Sanina D. V. Korchagin G. V. Shilov A. V. Kulikov A. F. Shestakov I. V. Sulimenkov S. M. Aldoshin 《Russian Journal of Coordination Chemistry》2010,36(12):876-886
Single crystals of an iron complex with 1-methyltetrazole-5-thiol of the formula [Fe2(SC2H3N4)2(NO)4] (I) were obtained and examined by X-ray diffraction. According to electrochemical data, tetranitrosyl binuclear complex I rapidly decomposes in protic solvents with elimination of NO. The maximum amount of NO generated by complex I in 1% aqueous DMSO is ∼900 nmol. This amount is reduced by half 15 min after the beginning of the decomposition under anaerobic
conditions. The dinitrosyl mononuclear intermediates [Fe(SC2H3N4)2(NO)]− and [Fe(SC2H3N4)2(NO)2]− were detected in solutions and identified by EPR spectroscopy and mass spectrometry. The low number of spins per complex
in solutions indicates that the mononuclear complexes undergo further decomposition into NO and the species [Fe(SC2H3N4)3]−, [SC2H3N4]−, and [Fe4S3(NO)7]−. Complex I was found to be substantially more stable in DMSO than in methanol and 1% aqueous DMSO. 相似文献