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1.
[MoVIO2(S2C2(CN)2)2]2− (┘1) and [MoIVO(S2C2(CN)2)2]2− (2) mimick oxidoreductase enzymatic activities of sulphite oxidase with biological electron donor, SO
3
2−
, andin vitro electron acceptor, [Fe(CN)6]3−, demonstrating proton coupled electron transfer reaction in water and inhibition of the oxidation of (2) in the presence of KCN. The sulphite exidizing system is characterized by substrate saturation kinetics indicating the biological
significance of the reactions 相似文献
2.
Wagner José Barreto Sonia Regina Giancoli Barreto Waleria Pickina Silva 《Transition Metal Chemistry》2009,34(6):677-681
The reaction between Fe(III) and dopamine in aqueous solution in the presence of Na2S2O3 was followed through UV–Vis spectroscopy, pH and oxy-reduction potential (Eh) measurements. The formation and quick disappearing
of the complex [Fe(III)HL1−]2+, HL1− = monoprotonated dopamine was observed with or without S2O3
2− at pH 3. An unexpected reaction occurs in presence of thiosulfate forming the stable anion complex [Fe(III)(L2−)2]1−, L2− = dopacatecholate (λ = 580 nm) and the auto-increasing of the pH, from 3 to 7. It was proposed that H+ and molecular oxygen are consumed by free radical thiosulfate formed during the reaction. 相似文献
3.
Contact precipitation of silver with a magnesium powder from 0.0025–0.01 M solutions of the system [Ag(CN)2]?-CN? in the hydrodynamic mode was studied. The dependence of the silver cementation rate in the initial stage on the concentration of the [Ag(CN)2]? complex and on the surface area of the cementing agent was examined, and the relationship of the temperature factor with the depolarization of silver reduction on microcathodes and acceleration of magnesium dissolution on microanodes was analyzed. 相似文献
4.
Accumulation of Silver(I) Ion and Diamine Silver Complex by <Emphasis Type="Italic">Aeromonas</Emphasis> SH10 biomass 总被引:1,自引:0,他引:1
The biomass of Aeromonas SH10 was proven to strongly absorb Ag+ and [Ag(NH3)2]+. The maximum uptake of [Ag(NH3)2]+ was 0.23 g(Ag) g−1(cell dry weight), higher than that of Ag+. Fourier transform infrared spectroscopy spectra analysis indicated that some organic groups, such as amide and ionized carboxyl
in the cell wall, played an important role in the process of biosorption. After SH10 cells were suspended in the aqueous solution
of [Ag(NH3)2]+ under 60°C for more than 12 h, [Ag(NH3)2]+ was reduced to Ag(0), which was demonstrated by the characteristic absorbance peak of elemental silver nanoparticle in UV-VIS
spectrum. Scanning electron microscopy and transmission electron microscopy observation showed that nanoparticles were formed
on the cell wall after reduction. These particles were then confirmed to be elemental silver crystal by energy dispersive
X-ray spectroscopy, X-ray diffraction, and UV-VIS analysis. This study demonstrated the potential use of Aeromonas SH10 in silver-containing wastewater treatment due to its high silver biosorption ability, and the potential application
of bioreduction of [Ag(NH3)2]+ in nanoparticle preparation technology. 相似文献
5.
In biological electron transport chains, [2Fe–2S] clusters have versatile electrochemical properties and serve as important
electron carriers in a wide variety of biological processes. To understand structural effects on the variation in reduction
potentials in [2Fe–2S] proteins, a series of [2Fe–2S] protein analogs with bidentate ligands ( − SC
2
H
4
NH
2) were recently produced by collision-induced dissociation of [Fe
4
S
4(L)4]2− (L = SC
2
H
4
NH
2). Combined with photoelectron spectroscopy findings, the reaction mechanisms of [Fe
4
S
4(L)4]2− to [Fe
2
S
2(L)2]− and the structural effects of ligands on the electronic and redox properties of the [2Fe–2S] clusters are investigated here
using broken-symmetry density functional theory method. Our calculations suggest that [Fe
2
S
2(η2 − L)(cis − L)]− and [Fe
2
S
2(η2 − L)2]− are the experimentally observed [2Fe–2S] products, which are generated via a fission process of [Fe
4
S
4(L)4]2− followed by rearrangement of ligands of [Fe
2
S
2(L)2]−. Moreover, structural variation of the ferrous center may dramatically affect the oxidation energy of the [2Fe–2S] clusters. 相似文献
6.
Hongmei Shi Shipeng Liu Shigang Shen Shuying Huo Weijun Kang 《Transition Metal Chemistry》2009,34(8):821-826
Kinetics of oxidation of dl-pipecolinate by bis(hydrogenperiodato)argentate(III) complex anion, [Ag(HIO6)2]5−, has been studied in aqueous alkaline medium in the temperature range of 25–40 °C. The oxidation kinetics is first order
in the silver(III) and pipecolinate concentrations. The observed second-order rate constant, decreasing with increasing [periodate]
is virtually independent of [OH−]. α-Aminoadipate as the major oxidation product of pipecolinate has been identified by chromatographic analysis. A reaction
mechanism is proposed that involves a pre-equilibrium between [Ag(HIO6)2]5− and [Ag(HIO6)(H2O)(OH)]2−, a mono-periodate coordinated silver(III) complex. Both Ag(III) complexes are reduced in parallel by pipecolinate in rate-determining
steps (described by k
1 for the former Ag(III) species and k
2 for the latter). The determined rate constants and their associated activation parameters are k
1 (25 °C) = 0.40 ± 0.02 M−1 s−1, ∆H
1≠ = 53 ± 2 kJ mol−1, ∆S
1≠ = −74 ± 5 J K−1 mol−1 and k
2 (25 °C) = 0.64 ± 0.02 M−1 s−1, ∆H
2≠ = 41 ± 2 kJ mol−1, ∆S
2≠ = −110 ± 5 J K−1 mol−1. The time-resolved spectra, a positive dependence of the rate constants on ionic strength of the reaction medium, and the
consistency of pre-equilibrium constants derived from different reaction systems support the proposed reaction mechanism. 相似文献
7.
Relativistic density functional calculations including scalar and spin-orbit effects via the ZORA approximation and including
solvent effects were carried out on the [Re6S8(CN)6]4−, [Re5MoS8(CN)6]5−, [Re4Mo2S8(CN)6]5−, [Re3Mo3S8(CN)6]5−, [Re2Mo4S8(CN)6]5−, [ReMo5S8(CN)6]5− and [Mo6S8(CN)6]6− clusters. By increasing the replacement of each Re atom with Mo atoms we find that for x > 2 the HOMO–LUMO gap decreases significantly. The calculated gap of the [Re3Mo3S8(CN)6]5−, [Re2Mo4S8(CN)6]5− and [ReMo5S8(CN)6]5− clusters is similar to the calculated and observed gap of the superconducting PbMo6S8 Chevrel phases. The current calculations also indicates that the electronic similarities of the lowest excited states of
the semiconducting 24e [Re5MoS8(CN)6]5− and 23e [Re4Mo2S8(CN)6]5− clusters with the strongly luminescent 24e [Re6S8(CN)6]4− cluster, suggest that these mixed metal clusters might be luminescent. 相似文献
8.
Mercury-mercury (II) sulphide electrode has been prepared and its electrochemical and thermodynamic behaviour has been studied
in different media. The electrode is found to show Nernstian response to pS (− log [S2−]) over the range 5.19–10.38. In the pH range 7.96–11.98, at constant [S2−]v, its response is also Nernstian. The values of thermodynamic functions, viz., ΔG0. ΔH0, and ΔS0 for the electrode reaction: Hg(3)+S2−
aμ
⇌HgS(s)+2e, have been determined. Further, the standard free energy of formation (ΔG
f
0
) and solubility product constant (K
vp
) of HgS in aqueous medium at 25±0.1°C have also been determined. 相似文献
9.
Yan Ding Hongli Chen Weilin Chen Enbo Wang Jingxin Meng 《Transition Metal Chemistry》2009,34(3):281-288
Four novel organic–inorganic hybrid compounds [Cu5
I(4,4′-bpy)3(2,2′-bpy)4][BW12O40] · H2O (1), [Ni0.5(2,2′-bpy)1.25][Ni(2,2′-bpy)3][Ni(2,2′-bpy)2(H2O)(SiW11VIWVO40)] · 0.5H2O (2), [H2bpy]2[Zn(2,2′-bpy)3]2[Si2W18O62] · 1.5H2O (3) and [CuII(2,2′-bpy)2]2[SiW12O40] · 2H2O (4) (2,2′-bpy = 2,2′-bipyridine, 4,4′-bpy = 4,4′-bipyridine) have been synthesized under hydrothermal conditions and characterized
by elemental analysis, IR spectroscopy, thermal gravimetric analysis, electrochemical measurements and single-crystal X-ray
diffraction. Compound (1) is a novel [BW12O40]5− polyoxoanion bisupported by copper(I) coordination cations with mixed 2,2′-bpy and 4,4′-bpy ligands. Compound (2) is constructed from the [SiW11VIWVO40]5− polyoxoanions supported by [Ni(2,2′–bpy)2]2+. Compound (3) is composed of a novel [Si2W18O62]8− cluster and [Zn(2,2′–bpy)3]2+ complexes, which held together into a three-dimensional (3D) supramolecular network through hydrogen-bonding interactions.
Compound (4) shows a 2D layer framework constructed from a bisupporting Keggin polyoxoanion cluster and [Cu(2,2′–bpy)2]2+ coordination polymer fragments, resulting in 3D networks via supramolecular interactions.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
10.
K Kiruthiga P Aravindan S Anandan P Maruthamuthu 《Research on Chemical Intermediates》2006,32(2):115-135
N,N,N′,N′-Tetramethylbenzidine (TMB) is an aromatic amine that undergoes oxidation by various oxidizing agents such as Ce4+, MnO−4, Cr2O2−7; HSO−5, S2O−8, H2O2, Cl2, Br2 and I2, thereby serving as a reducing substrate. One-electron oxidation of TMB results in a radical cation (TMB˙+), and on further oxidation leads to the product dication (TMB++) were monitored by stopped-flow spectrophotometer at the absorption wavelength of TMB˙+(λmax; 460 nm). ESR data was also provided to confirm the formation of radical cation. The rates of both the formation and decay
of TMB˙+ have been followed by a total second-order kinetics, a first-order dependence each on [TMB] (or) [TMB˙+] and [oxidant]. The kinetic and transition state parameters have been evaluated for the effects of pH and temperature on
the formation and decay of TMB˙+ and discussed with suitable reaction mechanisms. Also, the rate constants for the reactions of the radical cation with various
reducing agents such as sulfite (SO2−3), thiosulfate (S2O2−3), dithionite (S2O2−4) and disulfite (S2O2−5) and ascorbic acid (vitamin C, AH2 were determined. Besides these, this article also explains how TMB acts as a better electron relay than unsubstituted benzidine,
even though both of them undergo one-electron oxidation and are used in the chemical routes to solar energy conversions. The
observed rate constants for electron transfer were correlated theoretically using Marcus theory. The observed and calculated
rate constants have good correlation. 相似文献
11.
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
12.
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
13.
Rajarshi Chatterjee Mahammad Ali Michael G. B. Drew M. Nethaji Swastik Mondal Monika Mukherjee 《Transition Metal Chemistry》2009,34(1):1-5
Blue [{Cu(2,2′-bipy)2}2{α-SiW12O40}] (bipy = bipyridyl) (1) and pale yellow [Mn(2,2′-bipy)3]2[α-SiW12O40] (2) have been synthesized hydrothermally and characterized by IR spectroscopy and single crystal X-ray structure analysis. In
1, the [α-SiW12O40]4− ion acts as a bridge between the two [{Cu(2,2′-bipy)2]2+ moieties via coordination through the terminal oxygen atoms, while in 2, the [Mn(2,2′-bipy)3]2+ ion balances the charge on the polyoxo anion without forming any covalent bond. To the best of our knowledge, this is the
first example of transition metal-mediated transformation of [α-SiW9O34]10− to [α-SiW12O40]4−.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
14.
E. Yu. Matveev G. A. Razgonyaeva V. N. Mustyatsa N. A. Votinova K. Yu. Zhizhin N. T. Kuznetsova 《Russian Chemical Bulletin》2010,59(3):556-559
The reaction of the [B10H9O2C4H8]−, [B10H9OC4H8]−, and [B10H9OC5H10]− anions with negatively charged S-nucleophiles, such as SH−, SCN−, and S2O3
2−, resulted in the ring opening of the cyclic substituent and the formation of derivatives with the terminal thiol, thiocyanate,
and thiosulfate groups. The structures of the products were confirmed by the IR, mass, and 1H, 11B, and 13C NMR spectra. 相似文献
15.
Two stable thiazolylazo anion radical complexes of ruthenium(II), [Ru(L1•−)(Cl)(CO)(PPh3)2] (1) and [Ru(L2•−)(Cl)(CO)(PPh3)2] (2) (where L1 = 2′-Thiazolylazo-2-imidazole and L2 = 4-(2′-Thiazolylazo)-1-n-hexadecyloxy-naphthalene), have been synthesized
and characterized by spectroscopic and electrochemical techniques. The radical nature of the complexes has been confirmed
from their room temperature magnetic moments and X-band ESR spectra. The radical complexes display a moderately intense (ε ~ 104 M−1 cm−1) and relatively broad band in 430–460 nm region. In the microcrystalline state, complexes (1) and (2) display strong ESR
signals at g = 1.951 and g = 1.988, respectively. In CH2Cl2 solution, complexes (1) and (2) show a quasireversible one-electron response near −0.64 and −0.59 V, respectively, versus
Ag/AgCl due to the radical redox couple [RuII(L)(Cl)(CO)(PPh3)2]/[RuII (L•−)(Cl)(CO)(PPh3)2]. 相似文献
16.
J. W. Zhao X. F. Zhang P. T. Ma Y. Q. Feng J. P. Wang J. Y. Niu 《Russian Journal of Coordination Chemistry》2009,35(12):891-895
A Keggin organic-inorganic hybrid polyoxometalate combined with nickel complex [Ni (Dmf)3(H2O)][HPMo12O40] · (Dmf) · 2H2O (I) has been synthesized and structurally characterized by elemental analysis, IR spectrum, TG analysis, cyclic voltammetry,
and single-crystal X-ray diffraction. Interestingly, a two-dimensional supramolecular network is constructed by the [PMo12O40]3− polyanions, [Ni(Dmf)3(H2O)]2+ cations, and water molecules via hydrogen-bonding interactions. The cyclic voltammetric measurements illustrate that the [PMo12O40]3− polyanion is the electrochemical redox active center of I in the solution. 相似文献
17.
The two new compounds Mn(dien)2[MoS4] (1) and Mn(dien)2[Mo2O2S6] (2) (dien = diethylenetriamine) were prepared under solvothermal conditions. Both compounds were obtained as phase-pure products. The structures consist of new [Mn(dien)2]2+ cations and isolated tetrahedral [MoS4]2− (1) or [Mo2O2S6]2− (2) anions. Between the anions and the cations, hydrogen bonding is observed. Compound 1 crystallizes in the tetragonal space group I (a = 10.219(2), c = 9.259(2) ?, Z = 2), whereas 2 crystallizes in the monoclinic space group P21/c (a = 8.703(2), b = 18.390(4), c = 14.603(3) ?, β = 103.18(3)°, Z = 4). The thermal behaviour of the thiomolybdates was investigated using difference thermoanalysis (DTA) and thermogravimetry (TG). Both compounds decompose under argon with a single endothermic signal in the DTA curve (peak maximum: 252 (1) and 242°C (2)). 相似文献
18.
Summary. The two new compounds Mn(dien)2[MoS4] (1) and Mn(dien)2[Mo2O2S6] (2) (dien = diethylenetriamine) were prepared under solvothermal conditions. Both compounds were obtained as phase-pure products. The
structures consist of new [Mn(dien)2]2+ cations and isolated tetrahedral [MoS4]2− (1) or [Mo2O2S6]2− (2) anions. Between the anions and the cations, hydrogen bonding is observed. Compound 1 crystallizes in the tetragonal space group I (a = 10.219(2), c = 9.259(2) ?, Z = 2), whereas 2 crystallizes in the monoclinic space group P21/c (a = 8.703(2), b = 18.390(4), c = 14.603(3) ?, β = 103.18(3)°, Z = 4). The thermal behaviour of the thiomolybdates was investigated using difference thermoanalysis (DTA) and thermogravimetry
(TG). Both compounds decompose under argon with a single endothermic signal in the DTA curve (peak maximum: 252 (1) and 242°C (2)).
Received November 5, 2001. Accepted December 27, 2001 相似文献
19.
A. L. Gushchin M. N. Sokolov D. Yu. Naumov V. P. Fedin 《Journal of Structural Chemistry》2008,49(4):748-752
By the reaction of [Mo3S4(C2O4)3(H2O)3]2− with PdCl2 and NH4H2PO2 as a reducing agent, followed by the addition of PPh3, a new oxalate cuboidal cluster complex [Mo3(PdPPh3)S4(C2O4)3(H2O)3]2− is obtained. It was isolated and structurally characterized as K2[Mo3(PdPPh3)S4(C2O4)3(H2O)3]·0.5H2O.
Original Russian Text Copyright ? 2008 by A. L. Gushchin, M. N. Sokolov, D. Yu. Naumov, and V. P. Fedin
__________
Translated from Zhurnal Strukturnoi Khimii, Vol. 49, No. 4, pp. 775–778, May–June, 2008. 相似文献
20.
Chao Xu Jing-Jing Zhang Taike Duan Quan Chen Qian-Feng Zhang 《Journal of Cluster Science》2010,21(4):813-823