共查询到20条相似文献,搜索用时 15 毫秒
1.
Han-Ping Zhang Hong Zhou Zhi-Quan Pan Xiang-Gao Meng You Song 《Transition Metal Chemistry》2008,33(1):55-60
A novel linear trinuclear copper(II) complex bridged by phenoxy and benzyloxy oxygen atoms ([Cu3L2](ClO4)2 · (CH3CN)2, L = C11H13BrN2O2
2−) was synthesized and the crystal structure of the complex was determined by X-ray diffraction technique. The crystal structure
of the complex contains a linear trinuclear array of copper(II) ions in which the central copper(II) ion is in an octahedron
coordination sphere and lies on an inversion center of the molecule, the terminal ones are in an identical square pyramid
structure. Variable-temperature magnetic data indicate that the complex displays a strong antiferromagnetic coupling with
J = −270(8) cm−1 between the metal ions. 相似文献
2.
Zheng Fang Shaofen Wang Zhenghua Zhang 《Journal of Thermal Analysis and Calorimetry》2011,106(3):937-943
An experiment was done on electrochemical–calorimetry to identify the Peltier heats of the ferro-ferricyanide reversible electrode
reaction over the concentration range of 0.075–0.3 mol dm−3 at 298.15 K. A new approach has been developed to obtain the standard potential of this electrode, which was identified as
(+0.3580 ± 0.0030) volt at 298.15 K and compared with previously reported values. An equation derived from the approach is
also applied to several standard couples, such as Fe(CN)6−3/Fe(CN)6−4, H+/H2, Cu2+/Cu, Cl−/Hg2Cl2,Hg, Fe3+/Fe2+, and Cl−/Cl2 to determine their respective reaction heats with satisfying results. 相似文献
3.
Amitava Dutta Mahammad Ali Sumana Gangopadhyay Pradyot Banerjee 《Journal of Chemical Sciences》1994,106(4):881-886
The electron transfer reactions of Mo(CN)8
4, W(CN)8
4− and Fe(CN)6
4− with the manganese (III) complex oftrans-cyclohexane-1,2-diamine-N,N,N′,N′-tetraacetic acid have been studied by stopped-flow spectrophotometry in the pH range 2.0–6.5.
Analysis of kinetic data conforms to an outer-sphere process in each case. The validity of Marcus’ crossreaction relation
to these reactions is fairly satisfactory. 相似文献
4.
The sorption of anions H2PO4
−, HPO4
2−, PO4
3−, [Fe(CN)6]3−, and [Fe(CN)6]4− from aqueous solutions on the surface of FeIII and ZrIV oxyhydroxide hydrogels freshly precipitated at pH 4–13 was studied. The region of sorbate concentrations was from 0.00025
to 0.06 mol L−1. The plots of the anion uptakes vs. their equilibrium concentrations are represented by isotherms of the first type, which are well described by the Langmuir
equation if the quantity of the amount adsorbed is expressed as mol-site g−1. The maximum uptakes and constants of the Langmuir equation were calculated. The phosphate anions occupy the same number
of sorption sites on the sorbents precipitated at different pH. The average specific content of sorption sites for the ferro-
and zirconogels in the metastability period is independent of the pH of their precipitation, being 3.1·10−3 and 3.2·10−3 mol-site g−1, respectively. The [Fe(CN)6]3− and [Fe(CN)6]4− anions are sorbed only on the positively charged sites of the hydrogels and occupy not more than 2·10 mol-site g−1 in the studied interval of pH of precipitation.
__________
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1736—1741, August, 2005. 相似文献
5.
Four pyridinecarboxamide iron dicyanide building blocks and one Mn(III) compound have been employed to assemble cyanide-bridged
heterometallic complexes, resulting in a series of trinuclear cyanide-bridged FeIII–MnII complexes: {[Mn(DMF)2 (MeOH)2][Fe(bpb)(CN)2]2}·2DMF (1), {[Mn(MeOH)4][Fe(bpmb)(CN)2]2}·2MeOH·2H2O (2), {[Mn(MeOH)4][Fe(bpdmb)(CN)2]2}·2MeOH·2H2O (3) and {[Mn(MeOH)4][Fe(bpClb)(CN)2]2}·4MeOH (4) (bpb2− = 1,2-bis(pyridine-2-carboxamido)benzenate, bpmb2− = 1,2-bis(pyridine-2-carboxamido)-4-methyl-benzenate, bpdmb2− = 1,2-bis(pyridine-2-carboxamido)-4,5-dimethyl-benzenate, bpClb2− = 1,2-bis(pyridine-2-carboxamido)-4-chloro-benzenate). Single-crystal X-ray diffraction analysis shows their similar sandwich-like
structures, in which the two cyanide-containing building blocks act as monodentate ligands through one of their two cyanide
groups to coordinate the Mn(II) center. Investigation of the magnetic properties of these complexes reveals antiferromagnetic
coupling between the neighboring Fe(III) and Mn(II) centers through the bridging cyanide group. A best fit to the magnetic
susceptibilities of complexes 1 and 3 gave the magnetic coupling constants J = −1.59(2) and −1.32(4) cm−1, respectively. 相似文献
6.
Functionalized polypyrrole films were prepared by incorporation of Fe(CN)6
3− as doping anion during the electropolymerization of pyrrole at a glassy carbon electrode from aqueous solution. The electrochemical
behavior of the Fe(CN)6
3−/Fe(CN)6
4− redox couple in polypyrrole was studied by cyclic voltammetry. An obvious surface redox reaction was observed and dependence
of this reaction on the solution pH was illustrated. The electrocatalytic ability of polypyrrole film with ferrocyanide incorporated
was demonstrated by oxidation of ascorbic acid at the optimized pH of 4 in a glycine buffer. The catalytic effect for mediated
oxidation of ascorbic acid was 300 mV and the bimolecular rate constant determined for surface coverage of 4.5 × 10−8 M cm−2 using rotating disk electrode voltammetry was 86 M−1 s−1. Furthermore, the catalytic oxidation current was linearly dependent on ascorbic acid concentration in the range 5 × 10−4–1.6 × 10−2 M with a correlation coefficient of 0.996. The plot of i
p versus v
1/2 confirms the diffusion nature of the peak current i
p.
Received: 12 April 1999 / Accepted: 25 May 1999 相似文献
7.
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
8.
Papánková B. Vrbová M. Boča R. Šimon P. Falk K. Miehe G. Fuess H. 《Journal of Thermal Analysis and Calorimetry》2002,67(3):721-731
Heat flow to [Fe(bzimpy)2](ClO4)2⋅0.25H2O complex (bzimpy=2,6-bis(benzimidazol-2-yl)pyridine) (I) was measured between 300 and 460 K by differential scanning calorimetry. This exhibits a well-developed peak characteristic
of the first-order phase transitions at temperature 403 K. The enthalpy and entropy of transition from low-spin to high-spin
state has been determined to be ΔH=17 kJ mol−1 and ΔS=43.0 Jmol−1 K−1. Heat flow to [Fe(bzimpy−1H)2]⋅H2O complex (bzimpy
−1H=deprotonated bzimpy) (II) was measured between 300 and 580 K. The spin crossover in this system is accompanied with liberation of crystal water on
the first heating. To monitor the structural changes during the spin crossover, powder diffraction data have been collected
as a function of temperature.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
9.
Shen-Ming Chen Wen-Yan Chzo R. Thangamuthu 《Journal of Solid State Electrochemistry》2008,12(11):1487-1495
Electrochemically active hybrid coatings based on cationic films, didodecyldimethylammonium bromide (DDAB), and poly(diallyldimethylammonium
chloride) (PDDAC) are prepared on electrode surface by cycling the film-covered electrode repetitively in a pH 6.5 solution
containing Fe(CN)6
3− and Ru(CN)6
4− anions. Modified electrodes exhibited stable and reversible voltammetric responses corresponding to characteristics of Fe(CN)6
3−/4− and Ru(CN)6
4−/3− redox couples. The cyclic voltammetric features of hybrid coatings resemble that of electron transfer process of surface-confined
redox couple. Electrochemical quartz crystal microbalance results show that more amounts of electroactive anionic complexes
partitioned into DDAB coating than those doped into PDDAC coating from the same doping solution. Peak potentials of hybrid
film-bound redox couples showed a negative shift compared to those at bare electrode and this shift was more pronounced in
the case of DDAB. Finally, the advantages of hybrid coatings in electrocatalysis are demonstrated with sulfur oxoanions. 相似文献
10.
The remarkable enhancement of electron transfer on screen-printed carbon electrodes (SPCEs) with modification by iron nanoparticles
(Fenano), coupled with Fe(CN)6
4−/3− redox species, was characterized with an increase of electroactive area (A
ea) at electrode surface together with a decrease of heterogeneous electron transfer rate constant (k°) in the system. Hence, Fenano-Fe(CN)6
3− SPCEs with deposition of glucose oxidase (GOD) demonstrated a higher sensitivity to various glucose concentrations than Fe(CN)6
3−/GOD-deposited SPCEs. In addition, an inhibited diffusion current from cyclic voltammograms was also observed with an increase
in redox concentration and complicated the estimation of A
ea. Further analysis by the electrochemical impedance method, it was shown that this effect might be resulted from the electrode
surface blocking by the products of activated complex decomposition. 相似文献
11.
Stephanie A. Moore Subhash C. Bhattacharya Rama M. Palepu 《Journal of solution chemistry》2006,35(4):471-483
The photophyscial behavior of the dye Safranine T in the ground and excited states in aqueous mixtures of glycol oligomers was investigated by absorption and fluorescence spectroscopic techniques. The formation of a 1:1 complex in the excited state was inferred from fluorescence studies. The calculated equilibrium constants of the complex are directly proportional to the molar mass of the glycol. Microviscosity values of the aqueous glycol mixtures were determined by employing Auromine O as a fluorescence probe. Stokes shift values were correlated with the bulk dielectric constant and the microviscosity of the media. Also employing Stokes shifts, solvent parameters such as the Kowoser Z values and the intramolecular charge transfer energy, E
T
(30), were evaluated. The fluorescence quenching of Safranine T by the inorganic ions [Fe(CN)6]3−, [Fe(CN)6]4−, and [I]− in aqueous oligomer mixtures at a fixed concentration was investigated. The ions influenced the quenching process to different extents, and the efficiency of quenching of the dye in the glycol media for [Fe(CN)6]4− and [I]− ions follows the order EG > DEG > TEG > TTEG. In the case of ferricyanide ion the reverse order was observed. The microviscosity and bulk dielectric constant of the media played a major role in the collisional quenching process. 相似文献
12.
Andrea Schuy Theo Woike Dominik Schaniel 《Journal of Sol-Gel Science and Technology》2009,50(3):403-408
Photoswitchable hybrid materials are successfully prepared by embedding guanidinium nitroprussides (GuNP, (CN3H6)2[Fe(CN)5NO]) into mesopores of transparent xerogel monoliths. The such prepared hybrid materials exhibit a higher photostability than
the corresponding GuNP solutions, whereby the chemical stability of the [Fe(CN)5NO]2−-anion in titania gel is nearly infinite. By irradiation with light in the blue-green spectral range one nitrosyl isomer is
formed by a 180° rotation of the NO ligand changing the Fe–NO into a Fe–ON coordination (SI), which is detected by the shift
of the ν(NO) stretching vibration from 1945 cm−1 (Fe–NO) to 1820 cm−1 (Fe–ON). Consequently there is enough space around the NO-ligand for such movement in xerogel mesopores. The embedding in
silica xerogels increases the achievable population of the isomeric nitrosyl configuration to about 15% with respect to a
single crystalline powder where only 9% are reached. 相似文献
13.
Self-assembly of the precursor [Cu(L)]2+ (L = 3,10-dipropyl-1,3,5,8,10,12-hexaazacyclotetradecane) with hexacyanometalate [Fe(CN)6]3− produces a 3-D cyano-bridged Cu(II)–Fe(III) bimetallic assembly, [CuL]2[Fe(CN)6]ClO4 · H2O (1), characterized by single-crystal X-ray diffraction studies, and magnetic measurements. The crystallographic determination
reveals that each hexacyanoferromate(III) ion connects four copper(II) ions using four co-planar CN− groups which axially coordinate to the copper ion in a trans fashion forming trans-CuL(N≡C)2 moieties in (1). Magnetic studies reveal that (1) displays a ferromagnetic interaction between Cu(II) and Fe(III) through the CN linkage. 相似文献
14.
Feng-Ying Dong Jian-Min Dou Da-Cheng Li Xi-Ke Gao Da-Qi Wang 《Journal of inclusion phenomena and macrocyclic chemistry》2006,54(1-2):115-121
Two supramolecular crown ether complexes [Na(DC18C6-A)(H2O)]{[Na(DC18C6-A)][Cd(mnt)2]} (1) and [K(DC18C6-A)]2[Cd(mnt)2] (2) (DC18C6-A = cis-syn-cis-dicyclohexyl-18-crown-6, isomer A; mnt = maleonitriledithiolate) have been synthesized and characterized by elemental analysis,
FT-IR spectroscopy and X-ray single crystal diffraction. Complex 1 is composed of one [Na(DC18C6-A)(H2O)]+ complex cation and one {[Na(DC18C6-A)][Cd(mnt)2]}− complex anion and displays an infinite chain-like structure through N–Na–N interactions. In complex 2, [K(DC18C6-A)]+ complex cation and [Cd(mnt)2]2− complex anion afford a novel 1D ladder-like structure by N–K–N, N–K–S interactions. 相似文献
15.
V. N. Kiryushov L. I. Skvortsova T. P. Aleksandrova 《Journal of Analytical Chemistry》2011,66(5):510-514
Cyclic and direct voltammetry with linear potential sweep has been used for the investigation of the dependence of the reversibility
and reduction current in the system Fe(CN)63−/Fe(CN)64− on the concentrations of LiCl, NaCl, KCl, and CsCl solutions. The electrode was made of a graphite-epoxy composite and activated
by mechanically cutting a surface layer directly in the solution and deactivated by the long-term storage in the air. The
selected type of the graphite electrode and the method used to activate its surface provides the reversibility and diffusion
control of the electrode process in the system Fe(CN)63−/Fe(CN)64− regardless of the composition of the supporting solution. In the case of the deactivated electrode, the degree of irreversibility
of this process depends on the form and concentration of metal chloride in the supporting electrolyte and the diffusion transfer
is complicated by the adsorption of compounds formed between the ferricyanide and the cation of the supporting solution. 相似文献
16.
Marcin Opallo 《Journal of Solid State Electrochemistry》1998,2(5):347-354
The electrochemical redox reactions: Fe(CN)6
4−−e−↔ Fe(CN)6
3−, Ru(NH3)6
3++e−↔ Ru (NH3)6
2+ and Fc(CH2OH)2−e−↔ Fc(CH2OH)2
+ (Fc–ferrocene) were investigated in tetrabutylammonium halide hydrates at temperatures below and above the electrolyte melting
point. They were studied by cyclic voltammetry, potential step chronoamperometry and impedance spectroscopy. Freezing of
the electrolyte affects both the shape and position of the cyclic voltammogram on the potential scale. Also the shapes of
the current-time relationship and the impedance spectra change at temperatures below the melting point. It has been proposed
that this behaviour is caused by slow transport of the reactant and the heterogeneous nature of the electrolyte. The activation
energies of reactant transport are about four times larger in frozen electrolytes than those in liquid. It has been concluded
that reactant transport is restricted to the intergrain space of the electrolyte.
Received: 16 December 1997 / Accepted: 10 February 1998 相似文献
17.
W. Xinmin Q. Chuansong Q. Songsheng T. Zhicheng 《Journal of Thermal Analysis and Calorimetry》2007,90(2):569-573
Rare-earth perchlorate complex coordinated with glycine [Nd2(Gly)6(H2O)4](ClO4)6·5H2O was synthesized and its structure was characterized by using thermogravimetric analysis (TG), differential thermal analysis
(DTA), chemical analysis and elementary analysis. Its purity was 99.90%. Heat capacity measurement was carried out with a
high-precision fully-automatic adiabatic calorimeter over the temperature range from 78 to 369 K. A solid-solid phase transformation
peak was observed at 256.97 K, with the enthalpy and entropy of the phase transformation process are 4.438 kJ mol−1 and 17.270 J K−1 mol−1, respectively. There is a big dehydrated peak appears at 330 K, its decomposition temperature, decomposition enthalpy and
entropy are 320.606 K, 41.364 kJ mol−1 and 129.018 J K−1 mol−1, respectively. The polynomial equations of heat capacity of this compound in different temperature ranges have been fitted.
The standard enthalpy of formation was determined to be −8023.002 kJ mol−1 with isoperibol reaction calorimeter at 298.15 K. 相似文献
18.
Electrochemical behavior of unitary or binary self-assembled monolayers with thiol-derivatized cobaltous porphyrin 总被引:1,自引:0,他引:1
A new thiol-derivatized metalloporphyrin, 5-{3-methoxyl-4-(4-mercaptobutoxy)}phenyl-10,15,20-triphenylporphyrincobalt (MBPPCo),
has been synthesized. The electrochemical behavior of unitary or binary self-assembled monolayers (SAMs) of MBPPCo and thiols
with carboxylic terminal groups was investigated using Fe(CN)6
3−/4− and ascorbic acid (AA) as probe species. The binary modified electrode showed a small increase in peak current but a large
decrease in overpotential. However, in anionic electroactive species [Fe(CN)6
3−/4− or AA], either positively charged MBPPCo or negatively charged thiol SAMs solely, slow electron transfer kinetics was obtained
and the possible reasons for the discrepancy are discussed. 相似文献
19.
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
20.
V. N. Smirnov 《Kinetics and Catalysis》2011,52(2):166-169
The results of our experimental studies and an analysis of the published data on the rate constant for the reaction Fe + O2 = FeO + O in the forward (I) and reverse (−I) direction are reported. The data obtained in this work are described by the
expressions k
1 = 6.2 × 1014exp(−11100 K/T) cm3 mol−1 s−1 and k
−1 = 6.0 × 1013exp(−588 K/T) cm3 mol−1 s−1 (T = 1500–2500 K). The generalized expressions for the temperature dependences of these rate constants derived by combining
our results with the literature data can be presented as k
1 = 9.4 × 1014(T/1000)0.022exp(−11224 K/T) cm3 mol−1 s−1 (T = 1500–2500 K) and k
−1 = 1.8 × 1014(1000/T)0.37exp(−367 K/T) cm3 mol−1 s−1 (T = 200–2500 K). 相似文献