共查询到20条相似文献,搜索用时 78 毫秒
1.
Pritha Talukder Shyamapada Shit Heinrich N?th Matthias Westerhausen Alexander Nikolai Kneifel Samiran Mitra 《Transition Metal Chemistry》2012,37(1):71-77
A heterobimetallic cyano-bridged 1D coordination polymer of the composition [Ni(baepn)(μ-NC)Fe(CN)3(NO)(μ-CN)]n·3H2O has been synthesized by the reaction of nickel(II) nitrate hexahydrate, baepn (baepn = N, N′-bis(2-aminoethyl)-1,3-propanediamine), and sodium nitroprusside dihydrate in a methanol–water mixture. The complex was characterized
by physicochemical and spectroscopic methods. The crystal structure was established by single-crystal X-ray diffraction analysis.
It reveals cyano-bridged heterometallic chains consisting of alternating arrays of Ni(II) and Fe(II) atoms, both being embedded
in distorted octahedral environments. Low-temperature susceptibility measurements show the presence of weak antiferromagnetic
exchange interactions between paramagnetic Ni(II) centers (J = −0.46 cm−1) through long diamagnetic [Fe(CN)5(NO)]2− bridges. Spin state of the iron atom was established by 57Fe M?ssbauer spectroscopy. 相似文献
2.
N. A. Sanina L. A. Syrtsova N. I. Shkondina E. S. Malkova A. I. Kotel’nikov S. M. Aldoshin 《Russian Chemical Bulletin》2007,56(4):761-766
The tetranitrosyl iron complex with pyridine-2-yl [Fe2(SC5H4N)2(NO)4] (1) has higher NO-donating activity in 3% aqueous solutions of DMSO (pH 7.0, 25 °C) than the organic NO donor, viz., adduct of NO with diethylenetriamine (NO-adduct). The NO concentration was determined by the spectrophotometric method based
on the formation of an NO complex with hemoglobin (Hb). The apparent first-order rate constants of the studied reactions are
(6.15±0.6)·10−1 s−1 and (0.8±0.08)·10−1 s−1 for complex 1 and the NO-adduct, respectively, at an Hb concentration of 2·10−1 mol L−1 and the ratio [NO donor]/[Hb] = 10. The effect of Hb and [NO donor]/[Hb] ratio on the rate of NO generation from a solution
of complex 1 was studied. For a fourfold decrease in the concentration of complex 1 the reaction rate constant decreases to 0.5·10−4 s−1, whereas the fourfold increase in the Hb concentration results in the stabilization of complex 1.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 732–736, April, 2007. 相似文献
3.
O. G. Shakirova L. G. Lavrenova N. V. Kurat’eva D. Yu. Naumov V. A. Daletskii L. A. Sheludyakova V. A. Logvinenko S. F. Vasilevskii 《Russian Journal of Coordination Chemistry》2010,36(4):275-283
Mononuclear iron(II) coordination compounds with tris(pyrazol-1-yl)methane (HC(Pz)3) described as [Fe{HC(Pz)3}2]A2 × nH2O, where A = Cl−, Br−, I−, 1/2 SO42−, n = 0–7, were synthesized. The compounds were studied by static magnetic susceptibility measurements, IR and UV/Vis spectroscopy,
and powder X-ray diffraction. The crystal and molecular structures of all compounds were determined by single crystal X-ray
diffraction. 相似文献
4.
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
5.
Radhey M. Naik Raj K. Tiwari Pradeep K. Singh Shiv Bali S. Yadav Abhas Asthana 《Transition Metal Chemistry》2008,33(5):615-623
It is observed that Ag(I) catalyzes the rate of substitution of phenylhydrazine (PhNHNH2) into hexacyanoferrate(II), producing a cherry red colored complex, [Fe(CN)5PhNHNH2]3−. The reaction was monitored at 488 nm leading to the formation of the complex under the conditions: [Fe(CN)6]4− (5.0 × 10−3 mol dm−3), PhNHNH2 (2.0 × 10−3 mol dm−3), temperature (25 ± 0.1 °C), pH (2.8 ± 0.02), and ionic strength, I (0.02 mol dm−3), (KNO3). Under optimum conditions, absorbance at fixed times (A
t
) is linearly related to Ag(I) in the concentration range 10.79–97.08 ng cm−3, in the presence of several diverse ions. The highest percentage error and relative standard deviations in the entire range
of Ag(I) determination are found to be 2.5% and 0.16, with a detection limit of 8.75 ng cm−3 of silver(I). The experimental accuracies expressed in terms of percentage recoveries are in the range of 97.87–102.50. The
method was successfully applied for the determination of Ag(I) in a few synthetic samples and found to be in good agreement
with those obtained from atomic absorption spectrophotometry (AAS). The validity of the proposed method has also been tested
for Ag(I) determination in spiked drinking water samples. The present catalytic kinetic method (CKM) is highly sensitive,
selective, reproducible, and inexpensive. A review of recently published catalytic spectrophotometric methods for determination
of Ag(I) has also been presented for comparison. 相似文献
6.
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
7.
Sanina N. A. Syrtsova L. A. Psikha B. L. Shkondina N. I. Rudneva T. N. Kotel’nikov A. I. Aldoshin S. M. 《Russian Chemical Bulletin》2010,59(10):1994-1998
By an example of the iron cysteamine nitrosyl complex {Fe2[S(CH2)2NH3]2(NO)4}SO4··2.5H2O (CAC), it was shown for the first time that the hydrolysis of this NO donor in the presence of ferrocytochrome c (cyt c
2+) affords the iron nitrosyl complex NO-cyt c
2+, which serves as the NO depot. The rate constant of NO release from CAC was determined from the kinetics of the formation
of NO-cyt c
2+. At pH 3.0 the rate constant is (2.7±0.1)·10−3 s−1. Ferrocytochrome c produces a less stabilizing effect on CAC than deoxyhemoglobin (Hb). Thus in the presence of cyt c
2+, the reaction is completed in 1 h, whereas NO is released from a solution of CAC (2·10−4 mol L−1) in the presence of Hb during 40 h. The previously unknown stabilization of iron nitrosyl complexes by hemoglobin was found. 相似文献
8.
Jonathan F. Ojo Jide Ige Grace O. Ogunlusi Olanrewaju Owoyomi Esan S. Olaseni 《Transition Metal Chemistry》2006,31(3):337-339
The reactions between Fe(Phen)32+[phen = tris-(1,10) phenanthroline] and Co(CN)5X3− (X = Cl, Br or I) have been studied in aqueous acidic solutions at 25 °C and ionic strength in the range I = 0.001–0.02 mol dm−3 (NaCl/HCl). Plots of k2 versus √I, applying Debye–Huckel Theory, gave the values −1.79 ± 0.18, −1.65 ± 0.18 and 1.81 ± 0.10 as the product of charges (ZAZB) for the reactions of Fe(Phen)32+ with the chloro-, bromo- and iodo- complexes respectively. ZAZB of ≈ −2 suggests that the charge on these CoIII complexes cannot be −3 but is −1. This suggests the possibility of protonation of these CoIII complexes. Protonation was investigated over the range [H+] = 0.0001 −0.06 mol dm−3 and the protonation constants Ka obtained are 1.22 × 103, 7.31 × 103 and 9.90 × 102 dm6 mol−3 for X = Cl, Br and I, respectively. 相似文献
9.
Jonathan F. Ojo Jide Ige Grace O. Ogunlusi Olanrewaju Owoyomi Esan S. Olaseni 《Transition Metal Chemistry》2006,31(6):782-785
The kinetics of the reactions between Fe(phen)
3
2+
[phen = tris–(1,10) phenanthroline] and
Co(CN)5X3− (X = Cl, Br or I) have been investigated in aqueous acidic solutions at I = 0.1 mol dm−3 (NaCl/HCl). The reactions were carried out at a fixed acid concentration ([H+] = 0.01 mol dm−3) and the second-order rate constants for the reactions at 25 °C were within the range of (0.151–1.117) dm3 mol−1 s−1. Ion-pair constants K
ip for these reactions, taking into consideration the protonation of the cobalt complexes, were 5.19 × 104, 3.00 × 102 and 4.02 × 104 mol−1 dm−3 for X = Cl, Br and I, respectively. Activation parameters measured for these systems were as follows: ΔH* (kJ K−1 mol−1) = 94.3 ± 0.6, 97.3 ± 1.0 and 109.1 ± 0.4; ΔS* (J K−1) = 69.1 ± 1.9, 74.9 ± 3.2 and 112.3 ± 1.3; ΔG* (kJ) = 73.7 ± 0.6, 75.0 ± 1.0 and 75.7 ± 0.4; E
a
(kJ) = 96.9 ± 0.3, 99.8 ± 0.4, and 122.9 ± 0.3; A (dm3 mol−1 s−1) = (7.079 ± 0.035) × 1016, (1.413 ± 0.011) × 1017, and (9.772 ± 0.027) × 1020 for X = Cl, Br, and I respectively. An outer – sphere mechanism is proposed for all the reactions. 相似文献
10.
The sorption behavior of Sn(II) onto Haro river sand has been examined with respect to nature of electrolyte, agitation time,
dosage of sorbent and concentration of sorbate. Maximum sorption (95.5%) has been achieved from 0.034M hydrochloric acid solution
after equilibrating sorbate (2·10−5M) and sorbent (50 mg) for 120 minutes at aV/W ratio of 90 cm3·g−1. The kinetic data have been subjected to Morris-Weber and Lagergren equations. The kinetics of sorption proceeds a two stage
process consisting of a relatively slow initial uptake followed by a much rapid increase in the sorption. The rate constant
of intraparticle transport, Kd, comes out to be 8.75·10−8 mol·g−1·min−1/2 and the first order rate constant for sorption is 0.0416 min−1. The sorption data of Sn(II) onto Haro river sand followed Langmuir, Freundlich and Dubinin-Radushkevich (D-R) type isotherms.
The Langmuir constant,Q, related to sorption capacity and,b, related to sorption energy are computed to be 10.6±1.1 μmol·g−1 and 1123±137 dm3·mol−1, respectively. The D-R isotherm yields the values ofC
m=348±151 μmol·g−1 and β=−0.01044±0.0008 mol2·kJ−2 and ofE=6.9±0.3 kJ·mol−1. In all three isotherms correlation factor (γ) is ≥0.99. The influence of common anions and cations on the sorption has been
investigated. Zn(II), Mg(II), oxalate, Pb(II), Mn(II) and tartrate reduce the sorption significantly whereas Fe(II) causes
substantial increase in the sorption. It is essential that all ions causing a decrease in the sorption of Sn(II) must be absent
from the sorptive solution otherwise low sorption yields would result. 相似文献
11.
A highly precise and accurate method for the determination of minor amounts of iron by substoichiometric isotope dilution
analysis is described. The constant amount of Fe(III) is substoichiometrically extracted with 2·10−4M oxine in chloroform from the aqueous phase of pH 9.2–10.0 containing 6·10−3M tartrate. The interfering ions such as Mn(II), Co(II), Ni(II), Cu(II), and Zn(II), can be removed by the preliminary extraction
of Fe(III) from 7.5M hydrochloric acid solutions into isopropyl ether. The present method has been applied to the determination
of iron in biological standard reference materials, i.e., the NBS Spinach (SRM-1570) and the NIES Pepperbush (SRM No. 1),
and the results obtained are 548±9 ppm (NBS certified value: 550±20 ppm) and 193±4 ppm, respectively. 相似文献
12.
I. A. Poroshina N. P. Kotsupalo L. T. Menzheres V. P. Isupov 《Journal of Structural Chemistry》1994,35(5):709-719
Crystallochemical features of anion (Cl−, Br−, I−, NO
3
−
, CO
3
2−
, SO
4
2−
) varieties of the aluminum and lithium hydroxide were studied by using the aluminum and lithium binary hydroxide (LiOH·2Al(OH)3·2H2O) model in space group P63cm with the tetrahedral coordination of lithium. Atomic coordinates corresponding to the lowered lattice symmetry were refined.
Institute of Solid State Chemistry and Processing of Mineral Raw Materials, Siberian Branch, Russian Academy of Sciences.
Novosibirsk State Pedagogical University. Translated fromZhurnal Struktumoi Khimii, Vol. 35, No. 5, pp. 158–170, September–October, 1994.
Translated by T. Yudanova 相似文献
13.
Alaa Eldin M. Abdel-Hady 《Transition Metal Chemistry》2008,33(7):873-878
A kinetic study of the oxidation of [Co(H2L)(H2O)2]2+ (H2L = N,N-bis (salicylaldehyde-1,2-diaminoethane) Schiff base) by periodate in aqueous solution was performed over pH (2.3–3.4) range,
(0.1–0.5) mol dm−3 ionic strength and temperatures 20–35 °C for a range of periodate and complex concentrations. The reaction rate showed a
first-order dependence on both reactants and increased with pH over the range studied. The effects of Cu(II) and Fe(II) on
the reaction rate were investigated over the (1.0–9.0) × 10−5 mol dm−3 range. The reaction was inhibited as the concentration of Cu(II) increased, and it was independent on Fe(II) concentrations
over the ranges studied. An inner-sphere mechanism is proposed for the oxidation pathways of both the protonated and deprotonated
CoII complex species. 相似文献
14.
Joanna Wiśniewska 《Transition Metal Chemistry》2007,32(1):107-111
The kinetics of the oxidation of promazine by trisoxalatocobaltate(III) were studied in the presence of a large excess of
the cobalt(III) in tris buffer solution using u.v.–vis spectroscopy ([CoIII] = (0.6 − 2) × 10−3
M, [ptz] = 6 × 10−5
M, pH = 6.6–7.8, I = 0.1 M (NaCl), T = 288−308 K, l = 1 cm). The reaction proceeds via two consecutive reversible steps. In the first step, the reaction leads to formation of cobalt(II) species and a stable cationic
radical. In the second step, cobalt(III) is reduced to cobalt(II) ion and a promazine radical is oxidized to the promazine
5-oxide. Linear dependences of the pseudo-first-order rate constants (k
1 and k
2) on [CoIII] with a non-zero intercept were established for both redox processes. Rates of reactions decreased with increasing concentration
of the H+ ion indicating that the promazine and its radical exist in equilibrium with their deprotonated forms, which are reactive
reducing species. The activation parameters for reactions studied were as follows: ΔH≠ = 44 ± 1 kJ mol−1, ΔS≠ = −100 ± 4 JK−1 mol−1 for the first step and ΔH≠ = 25 ± 1 kJ mol−1, ΔS≠ = −169 ± 4 J K−1 mol−1 for the second step, respectively. Mechanistic consequences of all the results are discussed. 相似文献
15.
Joanna Wiśniewska 《Transition Metal Chemistry》2007,32(6):811-815
The kinetics of the electron-transfer reactions between promazine (ptz) and [Co(en)2(H2O)2]3+ in CF3SO3H solution ([CoIII] = (2–6) × 10−3
m, [ptz] = 2.5 × 10−4
m, [H+] = 0.02 − 0.05 m, I = 0.1 m (H+, K+, CF3SO
3
−
), T = 288–308 K) and [Co(edta)]− in aqueous HCl ([CoIII] = (1 − 4) × 10−3
m, [ptz] = 1 × 10−4
m, [H+] = 0.1 − 0.5 m, I = 1.0 m (H+, Na+, Cl−), T = 313 − 333 K) were studied under the condition of excess CoIII using u.v.–vis. spectroscopy. The reactions produce a CoII species and a stable cationic radical. A linear dependence of the pseudo-first-order rate constant (k
obs) on [CoIII] with a non-zero intercept was established for both redox processes. The rate of reaction with the [Co(en)2(H2O)2]3+ ion was found to be independent of [H+]. In the case of the [Co(edta)]− ion, the k
obs dependence on [H+] was linear and the increasing [H+] accelerates the rate of the outer-sphere electron-transfer reaction. The activation parameters were calculated as follows:
ΔH
≠ = 105 ± 4 kJ mol−1, ΔS
≠ = 93 ± 11 J K−1mol−1 for [Co(en)2(H2O)2]3+; ΔH
≠ = 67 ± 9 kJ mol−1, ΔS
≠ = − 54 ± 28 J K−1mol−1 for [Co(edta)]−. 相似文献
16.
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
17.
Nashwa M. H. Rizk 《Mikrochimica acta》2002,138(1-2):53-58
The construction and electrochemical response characteristics of poly(vinyl) chloride matrix membrane sensors for menadione
(vitamin K3) are described. Membranes incorporating the ion association complexes of menadione anion with bathophenanthroline nickel(II)
and iron(II) as electroactive materials show linear response for menadione over the range 10−1–10−5 M with anionic slopes of 58.2–51.4 mV per concentration decade. Both sensors exhibit fast response time (20–30 s), low detection
limit (2 × 10−5 M), good stability (4–6 weeks) and selectivity coefficient (10−1–10−3). Direct potentiometric determination of menadione under static and hydrodynamic mode of operations shows average accuracies
of 98.8 and 98.5% with relative standard deviations of 0.6% and 1.3%, respectively. Application of the method for the determination
of menadione in human plasma gives favourable results compared with those obtained by the standard spectrophotometric method.
Received February 26, 2001. Revision October 1, 2001. 相似文献
18.
T. V. Maltseva E. O. Kudelko V. N. Belyakov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2009,83(13):2336-2339
It was studied the equilibrium adsorption and adsorption kinetics of Cu(II), Cd(II), Pb(II), and Cr(VI) by composite hydroxides
formed by Me
x
O
y
· nH2O and Me0.4–0.7Al0.6–0.3O
y
· nH2O, where Me = Zr, Sn and Ti. It was estimated the values of the diffusion coefficients of adsorbed ions Cu(II) and Cr(VI)
from kinetic values. It was established that the estimated diffusion coefficients of adsorbed ions Cu(II) are in the range
0.4 × 10−12–2.5 × 10−12 m2/s for individual hydroxides and 1.2 × 10−12–2.8 × 10−12 m2/s for double hydroxides. The obtained values of diffusion coefficients Cr (VI) for double hydroxides are 0.1 × 10−10–0.4 × 10−10 m2/s. 相似文献
19.
20.
Melchor González-Dávila J. Magdalena Santana-Casiano Frank J. Millero 《Journal of solution chemistry》2006,35(1):95-111
The oxidation rates of nanomolar levels of Fe(II) in seawater (salinity S = 36.2) by mixtures of O2 and H2O2 has been measured as a function of pH (5.8–8.4) and temperature (3–35∘C). A competition exists for the oxidation of Fe(II)
in the presence of both O2 (μ mol⋅L−1 levels) and H2O2 (nmol⋅L−1 levels). A kinetic model has been applied to explain the experimental results that considers the interactions of Fe(II) with
the major ions in seawater. In the presence of both oxidants, the hydrolyzed Fe(II) species dominate the Fe(II) oxidation
process between pH 6 and 8.5. Over pH range 6.2–7.9, the FeOH+ species are the most active, whereas above pH 7.9, the Fe(OH)02 species are the most active at the levels of CO2−3 concentration present in seawater. The predicted Fe(II) oxidation rate at [Fe(II)]0 = 30nmol⋅L−1 and pH = 8.17 in the oxygen-saturated seawater with [H2O2]0 = 50nmol⋅L−1 (log 10 k = −2.24s−1) is in excellent agreement with the experimental value of log 10 k = −2.29s−1 ([H2O2]0 = 55nmol⋅L−1, pH = 8). 相似文献