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1.
Sofia Nikolaou Daniela M. Tomazela Marcos N. Eberlin Henrique E. Toma 《Transition Metal Chemistry》2008,33(8):1059-1065
The polymetallic [Ru3O(CH3COO)6(py)2(BPE)Ru(bpy)2Cl](PF6)2 complex (bpy = 2,2′-bipyridine, BPE = trans-1,2-bis(4-pyridil)ethylene and py = pyridine) was assembled by the combination of an electroactive [Ru3O] moiety with a [Ru(bpy)2(BPE)Cl] photoactive centre, and its structure was determined using positive ion electrospray (ESI-MS) and tandem mass (ESI-MS/MS)
spectrometry. The [Ru3O(CH3COO)6(py)2(BPE)Ru(bpy)2Cl]2+ doubly charged ion of m/z 732 was mass-selected and subject to 15 eV collision-induced dissociation, leading to a specific dissociation pattern, diagnostic
of the complex structure. The electronic spectra display broad bands at 409, 491 and 692 nm ascribed to the [Ru(bpy)2(BPE)] charge-transfer bands and to the [Ru3O] internal cluster transitions. The cyclic voltammetry shows five reversible waves at −1.07 V, 0.13 V, 1.17 V, 2.91 V and
−1.29 V (vs SHE) assigned to the [Ru3O]−1/0/+1/+2/+3 and to the bpy0/−1 redox processes; also a wave is observed at 0.96 V, assigned to the Ru+2/+3 pair. Despite the conjugated BPE bridge, the electrochemical and spectroelectrochemical results indicate only a weak coupling
through the π-system, and preliminary photophysical essays showed the compound decomposes under visible light irradiation. 相似文献
2.
Izaura Cirino Nogueira Diógenes Francisco Carlos Nart Mônica B. P. Mello Barreto Marcia Laudelina Arruda Temperini Ícaro de Sousa Moreira 《Journal of Solid State Electrochemistry》2007,11(11):1585-1590
Surface-Enhanced Raman Scattering (SERS) spectra of [Ru(CN)5(pyS)]4− (RupyS) complex self-assembled monolayer (SAM) were obtained on gold and silver surfaces at 632.8 and 413.1 nm excitation
radiations, respectively. The bands assigned to the heme iron of the cytochrome c (cyt c) metalloprotein group were observed
by using the RupyS SAM on silver at 413.1 nm. The Surface-Enhanced Resonance Raman Scattering (SERRS) spectra of the RupyS
SAM on silver in the cyt c solution obtained at −0.2 and +0.2 V present bands at 1,365 and 1,374 cm−1 characteristic of the heme group, indicating the reduced and oxidized states of this protein, respectively. The bands observed
at 1,464, 1,504, and 1,638 cm−1 are used to confirm the redox state of cyt c. The presence of the oxidized and reduced bands in function of different applied
potential is an evidence that the protein is interacting with the modifier.
This paper is dedicated to Prof. Francisco Nart, in memoriam. 相似文献
3.
Single- and two-component self-assembled organic monolayers (SAM) formed of HS-C10H20-COOH and the HS-C10H20-COOH + HS-C6H12-OH mixture and applied on gold electrodes of different shapes and roughness are studied. The resulting monolayers are characterized
in 1 M NaNO3 solutions by the methods of electrochemical impedance spectroscopy in the frequency range from 1 Hz to 100 kHz and cyclic
voltammetry in the potential range from 0 to −0.4 V (SCE). Using these method, the behavior of modified single-crystal and
polycrystalline gold electrodes in electrolyte solutions of different acidity is assessed and the standard rate constants
for the Ru[(NH3)6]3+/2+ redox reaction are determined. The SAM film formed from the ethanol solution of the HS-C10H20-COOH + HS-C6H12-OH mixture (0.025 M) on the Au(210) singlecrystal face lowers down the rate of the heterogeneous Ru[(NH3)6]3+/2+ reaction from 1.5 to 4.02 × 10−4 cm/s in the electrolyte solution with pH from 2. In solutions with higher pH, the rate constant is higher by almost an order
of magnitude (2.74 × 10−3 cm/s). The distribution of micropores in SAM films is studied within the framework of a model of micro-array electrodes.
The results of studies are compared with the literature data on the gold electrode in solutions of inactive electrolytes in
the absence and in the presence of SAM films formed by alkylmercaptans with equal chain lengths. 相似文献
4.
I. E. Animitsa E. N. Dogodaeva S. S. Nokhrin O. A. Kosareva A. Ya. Neiman 《Russian Journal of Electrochemistry》2010,46(7):734-740
Perovskite phases Ba3In2ZrO8 and Ba4In2Zr2O11 with the nominal concentration of structural oxygen vacancies 1/9 and 1/12, respectively, were synthesized by solid-phase
and solution methods. X-ray diffraction showed cubic symmetry of both phases with the unit cell parameter a = 0.4193(2) and 0.4204(3) nm, respectively. The absence of superstructural lines resulted in the conclusion on statistical
arrangement of oxygen vacancies. Thermogravimetry and mass spectrometry proved that both phases can reversibly absorb water
from gas phase (pH2O = 2 × 10−2 atm) with observed correlation between the concentration of oxygen vacancies and amount of absorbed water. The total water
amount was up to 0.9 mol per formula unit or, if recalculated for perovskite unit ABO3, 0.3 and 0.23 mol H2O, respectively. The temperature curves of coductivity in the atmosphere with various partial water vapor pressures (pH2O = 3 × 10−5 and 2 × 10−2 atm) showed significantly higher conductivity and lower activation energy (0.52 eV) in humid atmosphere due to proton transfer.
The proton conductivity is up to 5 × 10−4 Ohm−1 cm−1 at 300°C for Ba3In2ZrO8 specimen. IR spectrometry showed that protons in the structure exist primarily in OH-groups. 相似文献
5.
L. M. Dubova 《Russian Journal of Electrochemistry》2010,46(1):81-89
Surface properties of a modified single-crystal silver (111) face are studied in aqueous 1 M NaNO3 solutions with different acidity in the presence of a monolayer n-decanethiol (DT) film by the methods of electrochemical impedance spectroscopy (EIS) and cyclic voltammetry that employs
the meniscus contact technique. It is shown experimentally that in the potential range from 0 to −0.5 V, a DT-modified silver
electrode in NaNO3 solutions with pH 6 behaves as an ideal capacitance in a wide frequency range (from 0.01 Hz to 100 kHz). It is found that
with the increase in the solution acidity up to pH 4 and 2, the region of stable capacitance characteristics narrows down.
The concomitant changes in the adsorbed monolayer structure lead to deviations of impedance characteristics measured using
a low-frequency ac signal from those of the ideal capacitance. A potential shift to values more negative than −0.5 V leads
to the destruction of the monolayer. Based on the analysis of experimental EIS characteristics, system’s deviation from the
ideal behavior that may indicate violation of the layer continuity is assessed and the relaxation frequencies of the DT/Ag(111)
interface in solutions of different acidity are calculated. Estimates of capacitance, resistance, and thickness of the adsorbed
monolayer are obtained as a function of the solution pH. 相似文献
6.
The impedance spectra of CeF3/CeF3 bicrystal (two single crystals separated by a single intercrystalline boundary) between Ag-electrodes are studied over a
135 to 410 K temperature interval (including temperatures below room temperature). The bicrystal was prepared by thermal-diffusion
welding under a pressure of 1.5 × 107 Pa at 1473 K in vacuum (∼10−2 Pa). It is shown that the intercrystalline boundary affects but insignificantly the bicrystal bulk impedance. The CeF3/CeF3 ionic conductivity is 3 × 10−6 S/cm at 293 K; it is mainly determined by transfer processes in the single crystal bulk. 相似文献
7.
J. Goslar M. Wojciechowska M. Pietrowski M. Zieliński 《Research on Chemical Intermediates》2007,33(8):841-851
Electron paramagnetic resonance (EPR) and infrared (IR) spectroscopy were used to study the formation of ruthenium and adsorbed
species appearing on the catalyst upon the adsorption of CO and O2 on 1.37 wt% Ru/MgF2 catalysts derived from Ru3(CO)12. The presence of Ru
x+ sites in spite of a reductive H2 treatment at 673 K was observed by EPR and IR spectroscopy beside metallic Ru0 species. Both IR and EPR results provided clear evidence for the interaction between surface ruthenium and probe molecules.
The IR spectra recorded after admission of CO showed a band at approx. 2000 cm−1, due to linearly adsorbed CO on Ru0/MgF2 and two bands at higher frequencies (approx. 2140 and approx. 2070 cm−1), related to CO on oxidized Ru
n+ species, e.g., to Ru(CO)3 complex with Ru in the 1+ and/or 2+ state of oxidation and Ru(CO)2 with Ru in the 3+ and/or 4+ state of oxidation. A weak anisotropic EPR signal with g
‖ = 2.017 and g
⊥ = 2.003 is due to O
2
−
radicals and a formation of Ru4+-O
2
−
complex is postulated. The Ru3+ appears to oxidize to Ru4+ and the resulting dioxygen anion is coordinated to the ruthenium. The strong, isotropic EPR signal at g
0 = 2.003 detected upon admission of CO is attributed to CO radical anion rather than to any ruthenium carbonyl complexes. 相似文献
8.
Li XiaoHong Dong JinLing Xiao HanShuang Lu PeiDong Hu YongAn Zhang YunHong 《中国科学B辑(英文版)》2008,51(2):128-137
The efflorescence and deliquescence processes of Mg(NO3)2 aerosol particles deposited on ZnSe substrate have been investigated through in situ Fourier transform infrared-attenuated total reflection (FTIR-ATR) technique at the molecular level. At relative humidity
(RH) of ∼3%, Mg(NO3)2 particles existed as amorphous states. The amorphous Mg(NO3)2 particles were transformed into crystalline Mg(NO3)2 · nH2O (n ≤ 5) with slight increasing of RH. Thermodynamically stable Mg(NO3)2·6H2O crystals were gradually formed on the particle surface and started to be dissolved at the saturation point (∼53% RH). At
the same time, a continuous phase transition from Mg(NO3)2 · nH2O (n≤5) to Mg(NO3)2·6H2O occurred on the particle surface. This led the solid particles to completely deliquesce at 76% RH, which was much higher
than the saturation point of 53% RH. In the efflorescence process, Mg(NO3)2 droplets entered into the supersaturated region due to the gradual evaporation of water. Finally, amorphous particles were
formed when RH decreased below 5%. In the FTIR-ATR spectra of the supersaturated Mg(NO3)2 droplets, the absorbance of the symmetric stretching vibration of NO
3
−
(v
1- NO
3
−
) clearly became stronger. It resulted from the continuous formation of solvent share ion pairs (SIPs), and even the contact
ion pairs (CIPs) between Mg2+ and NO
3
−
.
Supported by the Trans-Century Program Foundation for the Talents by the Ministry of Education of China, the National Natural
Science Foundation of China (Grant Nos. 20073004, 20473012, and 20673010), the 111 Project (B07012), and the State Key Laboratory
of Physical Chemistry for Solid Surface of Xiamen University 相似文献
9.
Fabio Carniato Andrea Secco Giorgio Gatti Leonardo Marchese Enrico Sappa 《Journal of Sol-Gel Science and Technology》2009,52(2):235-241
The reaction of Ru3(CO)12 with 2(diphenylphosphino)ethyl-triethoxysilane (DPTS) in hydrocarbons, leads to the functionalized Ru3(CO)12−n
[Ph2P(CH2)2Si(OEt3)]
n
(n = 1,2) complexes. The complex with two phosphine substituents was chemically anchored on mesoporous silicas, SBA-15 and MCM-41,
in order to obtain two hybrid materials characterized by a different localization of the metal centre on the surface of the
porous supports. A detailed investigation of the cluster, before and after chemical anchoring on the mesoporous silicas, was
pursued. Particular attention was also devoted to the study of the morphological, structural and textural properties of the
metal-functionalised silicas (Ru/SBA-15 and Ru/MCM-41) by infrared spectroscopy (FT-IR), scanning electron microscopy, X-ray
diffraction and N2 physisorption analysis. 相似文献
10.
V. V. Drozdova E. A. Malinina L. V. Goeva I. N. Polyakova N. T. Kuznetsov 《Russian Journal of Inorganic Chemistry》2010,55(1):34-39
A method for the synthesis of the silver(I) complex with the closo-decaborate anion and triphenylphosphine [Ag2(Ph3P)2B10H10]
n
was developed and the structure of this complex was studied. The polymeric chain of the complex is formed with participation
of Ag(I) atoms, which coordinate the B10H102− anions through the apical (B(1)–B(2), B(9)–B(10)) and equatorial (B(3)–B(6), B(5)–B(8)) edges, the metalligand bonding occurring
through three-center two-electron bonds (MHB). The P atoms of two triphenylphosphine molecules are also incorporated in the
inner coordination sphere of the metal: the CN of the silver atom is 4 + 1. 相似文献
11.
G. M. Maksimov R. I. Maksimovskaya O. A. Kholdeeva M. A. Fedotov V. I. Zaikovskii V. G. Vasil’ev S. S. Arzumanov 《Journal of Structural Chemistry》2009,50(4):618-627
Heteropoly acid (HPA) H8(PW11TiO39)2O·xH2O (I) is synthesized by three different ways and studied by chemical analysis, potentiometric titration, mass-spectrometry, IR,
31P, 183W, and 17O NMR spectroscopy, thermogravimetry, and transmission electron microscopy. Anion I consists of two subparticles of the Keggin structure bridged by Ti-O-Ti. The dimeric anion exists in HPA aqueous solutions
at [I] > 0.02 M. At pH > 0.6 it splits to a [PW11TiO40]5− monomer stable up to pH ∼ 6. When heated (150–400)°C, I splits into H3PW12O40 and, apparently, H3PW10Ti2O38 without phase separation. Thermolysis products are soluble and when dissolved in water turn again into I. Complete decomposition of I to oxides occurs at ∼450°C. 相似文献
12.
A. N. Mansurova R. I. Gulyaeva V. M. Chumarev V. P. Mar’evich 《Journal of Thermal Analysis and Calorimetry》2010,101(1):45-47
Homogeneous manganocolumbite (MnNb2O6) was synthesized from Nb2O5 and MnO oxides. Powder sample was orthorhombic with unit cell parameters: α = 0.5766 nm, b = 1.4439 nm, c = 0.5085 nm and V = 0.4234 nm3. Heat capacity over the temperature range of 313–1253 K was measured in an inert atmosphere with combined thermogravimetry
and calorimetry using NETZSCH STA 449C Jupiter thermoanalyzer. Melting point was 1767 ± 3 K, enthalpy of melting was 144 ± 4 kJ mol−1. Experimental heat capacity of MnNb2O6 is fitted to polynomial C
pm = 221.46 + 3.03 · 10−3 T + −39.79 · 105 T
−2 + 40.59 · 10−6 T
2. 相似文献
13.
R. G. Bulgakov Yu. G. Ponomareva Z. S. Muslimov F. G. Valyamova R. A. Sadykov R. F. Tuktarov 《Russian Chemical Bulletin》2007,56(2):211-219
Fullerenyl radicals (FR) RC60
· and chemiluminescence (CL) are generated in the presence of O2 in C60—R3Al (R = Et, Bui) solutions in toluene (T = 298 K). The FR are formed due to the addition of the R· radical, which is an intermediate of R3Al autooxidation, to C60. Mass spectroscopy and HPLC were used to identify EtnC60Hm (n, m = 1–6), EtpC60 (p = 2–6), and dimer EtC60C60Et as stable products of FR transformations. As found by ESR, the EtC60
· radical (g = 2.0037) is also generated by photolysis of solutions obtained after interaction in the (C60— R3Al)—O2 system. In the presence of dioxygen, the FR is not oxidized but yields complexes with O2, which appear as broadening of the ESR signals. Chemiluminescence arising in the (C60—R3Al)—O2 system is much brighter (I
max = 1.86·108 photon s−1 mL−1) than the known background CL (I
max = 6.0·106 photon s−1 mL−1) for the autooxidation of R3Al and is localized in a longer-wavelength spectral region (λmax = 617 and 664 nm). This CL is generated as a result of energy transfer from the primary emitter 3CH3CHO* to the products of FR transformation: RnC60Hm, RpC60, and EtC60C60Et.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 205–213, February, 2007. 相似文献
14.
Elizabeth A. Turner Harald Rösner Yining Huang John F. Corrigan 《Journal of Cluster Science》2007,18(3):764-771
Mercury-selenosulfide (HgSe
x
S
1-x
) nanoparticles have been synthesized using the single-source reagent Me3Si–SeS–SiMe3. The reagent distributes Se2− and S2− to the metal core as the reaction between Me3Si–SeS–SiMe3 and mercury acetate occurs via a redox pathway, ultimately giving rise to Se–S bond cleavage. Particles are characterized
by EDX, TEM and powder X-ray diffraction analysis in conjunction with UV–Visible absorption spectroscopy.
Dedicated to Prof. Dr. Dieter Fenske on the occasion of his 65th birthday. 相似文献
15.
L. S. Nikolaeva A. N. Semenov L. I. Burova 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2010,84(12):2039-2046
Chemical equilibria in the high-molecular-weight heparin (Na4hep)-arginine (HArg)-H2O-NaCl and MCl2-Na4hep-HArg-H2O-NaCl systems of electrolytes (M = Ca2+, Mg2+) were calculated by the method of mathematical simulation of chemical equilibria from representative planned pH-metric titration
experiment at 2.30 ≤ pH ≤ 10.50 in a physiological solution medium in the presence of 0.154 M NaCl as a background electrolyte
at 37°C. The initial concentrations of the basic components were n × 10−3 M (n ≤ 4). 相似文献
16.
The complex impedance method in the temperature range of 291–660 K was used to study conductivity of oxofluoride BiO0.1F2.8 belonging to the tysonite structural type (LaF3). Bismuth oxofluoride was synthesized using a solid-phase method at 770–870 K for 1–2 h in an argon atmosphere. Heterovalent
substitution of fluoride ions F− by oxygen ions O2− in the anionic BiF3 matrix sublattice results in high ionic conductivity (∼0.1 S/cm at 660 K) of BiO0.1F2.8 ceramic samples. 相似文献
17.
H. López-González M. Jiménez-Reyes M. Solache-Ríos A. Rojas-Hernández 《Journal of Radioanalytical and Nuclear Chemistry》2007,274(1):103-108
Solubility product (Lu(OH)3(s)⇆Lu3++3OH−) and first hydrolysis (Lu3++H2O⇆Lu(OH)2++H+) constants were determined for an initial lutetium concentration range from 3.72·10−5 mol·dm−3 to 2.09·10−3 mol·dm−3. Measurements were made in 2 mol·dm−3 NaClO4 ionic strength, under CO2-free conditions and temperature was controlled at 303 K. Solubility diagrams (pLuaq vs. pC
H) were determined by means of a radiochemical method using 177Lu. The pC
H for the beginning of precipitation and solubility product constant were determined from these diagrams and both the first
hydrolysis and solubility product constants were calculated by fitting the diagrams to the solubility equation. The pC
H values of precipitation increases inversely to [Lu3+]initial and the values for the first hydrolysis and solubility product constants were log10
β*
Lu,H
= −7.92±0.07 and log10
K*sp,Lu(OH)3 = −23.37±0.14. Individual solubility values for pC
H range between the beginning of precipitation and 8.5 were S
Lu3+ = 3.5·10−7 mol·dm−3, S
Lu(OH)2+ = 6.2·10−7 mol·dm−3, and then total solubility was 9.7·10−7 mol·dm−3. 相似文献
18.
The rate constants of the reactions of the chlorine atom with C3F7I (k
1) and CF3I (k
2) have been measured using the resonance fluorescence of chlorine atoms in a flow reactor at 295 K: k
1 = (5.2 ± 0.3) × 10−12 cm3 molecule−1 s−1 and k
2 = (7.4 ± 0.6) × 10−13 cm3 molecule−1 s−1. No iodine atoms have been detected in the reaction products. 相似文献
19.
Rajeev K. Sinha Edith Nicol Vincent Steinmetz Philippe Maître 《Journal of the American Society for Mass Spectrometry》2010,21(5):758-772
Gas-phase infrared photodissociation spectroscopy is reported for the microsolvated [Mn(ClO4)(H2O)
n
]+ and [Mn2(ClO4)3(H2O)
n
]+ complexes from n = 2 to 5. Electrosprayed ions are isolated in an ion-trap where they are photodissociated. The 2600–3800 cm−1 spectral region associated with the OH stretching mode is scanned with a relatively low-power infrared table-top laser, which
is used in combination with a CO2 laser to enhance the photofragmentation yield of these strongly bound ions. Hydrogen bonding is evidenced by a relatively
broad band red-shifted from the free OH region. Band assignment based on quantum chemical calculations suggest that there
is formation of water—perchlorate hydrogen bond within the first coordination shell of high-spin Mn(II). Although the observed
spectral features are also compatible with the formation of structures with double-acceptor water in the second shell, these
structures are found relatively high in energy compared with structures with all water directly bound to manganese. Using
the highly intense IR beam of the free electron laser CLIO in the 800–1700 cm−1, we were also able to characterize the coordination mode (η2) of perchlorate for two clusters. The comparison of experimental and calculated spectra suggests that the perchlorate Cl—O
stretches are unexpectedly underestimated at the B3LYP level, while they are correctly described at the MP2 level allowing
for spectral assignment. 相似文献
20.
Quantum-chemical calculations of the geometry and energies of nine possible isomers of 12-vertex cobaltacarborane CpCoC2B9H11 (1) were carried out by the DFT method (PBEPBE/DGDZVP/DGA1). Thermodynamic stability of the isomers increases with increasing
distance between the carbon atoms in the cage and is virtually independent of the position of the CpCo vertex. The relative
stabilities of the 1,2,3-(17.57 kcal mol−1), 1,2,4-(3.72 kcal mol−1), and 1,2,9-isomers of 1 (0 kcal mol−1) are similar to the corresponding values for the ortho (17.61 kcal mol−1), meta (3.21 kcal mol−1), and para isomers (0 kcal mol−1) of carborane C2B10H12. The results of the present study confirm a close similarity of the CpCo and BH fragments in metallacarborane chemistry.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1557–1559, July, 2005. 相似文献