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1.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1988,44(5):527-528
It is found that the broadening of the 1100-cm−1 line of SO−24, caused by increasing [H3O+], is unaffected by addition of 4 M LiCl, NaBr, KCl and NH4Cl. This finding is in line with the lack of influence of NaCl reported earlier. The significance of these findings, in terms of the reaction mechanism, is discussed. 相似文献
2.
3.
《Chemical physics letters》1985,122(5):489-492
The rate constant for the bimolecular reaction CO + N2O → CO2 + N2 was determined by comparison of calculated infrared emission profiles of CO2 with those observed in shock-tube experiments in the temperature range 1350–2100 K for CO-N2O-He-Ar mixtures. The rate constant was found to be k1 = 3.2 × 1011exp(−85 kJ/RT) cm3 mol−1 s−1. 相似文献
4.
Lian-Sheng Ling Zhi-Ke He Gong-Wu Song He-You Han Hua-Shan Zhang Yun-E Zeng 《Mikrochimica acta》2000,134(1-2):57-62
A novel fluorimetric method has been developed for selective determination of DNA with the molecular “Light Switch” complex
of Ru(bipy)2(dppz)2+. The maximum fluorescence intensity was produced in the pH range of 9.3–11.5, with the maximum excitation and emission wavelength
of 471.8 nm and 599.8 nm, respectively. Under the optimum conditions, the fluorescence intensity was in proportion to the
concentration of DNA. The linear range for calf thymus DNA salmon sperm DNA and herring sperm DNA reaches from the limit of
determination to 1.5 μg/mL. The limits of determination for calf thymus DNA salmon sperm DNA and herring sperm DNA are 3.3 ng/mL,
2.8 ng/mL and 4.4 ng/mL, respectively. When the proposed method was used to determine DNA in the presence of some coexisting
substances, a satisfactory result was obtained.
Received December 29, 1998. Revision June 28, 1999. 相似文献
5.
Martínez R Enríquez PA Puyuelo MP González M 《The journal of physical chemistry. A》2012,116(21):5026-5029
The O((3)P) + CH(4) reaction has been investigated using the quasi-classical trajectory (QCT) method and an ab initio pseudotriatomic potential energy surface (PES). This has been mainly motivated by very recent experiments which support the reliability of the triatomic modeling even at high collision energy ( = 64 kcal mol(-1)). The QCT results agree rather well with the experiments (translational and angular distributions of products); i.e., the ab initio pseudotriatomic modeling "captures" the essence of the reaction dynamics, although the PES was not optimized for high E(col). Furthermore, similar experiments on the O((3)P) + CD(4) reaction at moderate E(col) (12.49 kcal mol(-1)) have also been of a large interest here and, under these softer reaction conditions, the QCT method leads to results which are almost in quantitative agreement with experiments. The utility of the ab initio pseudotriatomic modeling has also been recognized for other analogous systems (X + CH(4)) but with very different PESs. 相似文献
6.
Two [Cr(C2O4)2(AB)]2– type complexes, obtained from the reaction of cis-[Cr(C2O4)2(H2O)2]– with the AB ligand, [AB = picolinic (pyac) or 2-pyridine-ethanoic acid (pyeac) anions], were converted into [Cr(C2O4)(pyac)(H2O)2]0 and [Cr(C2O4)(pyeac)(H2O)2]0 compounds, respectively via FeIII-induced substitution of the oxalato ligand. The aquation products were separated chromatographically and their spectral characteristics and acid dissociation constants determined. The kinetics of the oxalato ligand substitution were studied with a 10–40 fold excess of FeIII over [CrIII] at [H+] = 0.2 M and at constant ionic strength 1.0 M (Na+, H+, Fe3+, ClO–
4). The reaction rate law is of the form: r = k
obs[CrIII], where k
obs = kQ[FeIII]/(1 + Q[FeIII]). The first-order rate constants (k), preequilibria quotients (Q) and activation parameters derived from the k values have been determined. The reaction mechanism is discussed in terms of a Lewis acid catalyzed (induced) ligand substitution. 相似文献
7.
《Journal of organometallic chemistry》1991,407(2):C13-C15
The dianion [Ru10C(CO)24]2− in CH2Cl2 reacts with CO under ambient conditions to produce quantitative amounts of the species [Ru3(CO)12] and [Ru6C(CO)16]2−; the hydrido-anion [HRu10C(CO)24]− reacts similarly to form [Ru6C(CO)16]−. 相似文献
8.
R. V. Panin N. R. Khasanova A. M. Abakumov W. Schnelle J. Hadermann E. V. Antipov 《Russian Chemical Bulletin》2006,55(10):1717-1722
Sodium ruthenium(III,IV) oxide Na1−x
Ru2O4 was synthesized by the solid state reaction of Na2CO3 and RuO2 in inert atmosphere and characterized by X-ray powder diffraction, electron diffraction, and high-resolution transmission
electron microscopy. The compound crystallizes in the CaFe2O4-type structure (space group Pnma, Z = 4, a = 9.2641(7) Å, b = 2.8249(3) Å, c = 11.1496(7) Å). Double rutile-like chains of the RuO6 octahedra form a three-dimensional framework, whose tunnels contain sodium cations. The structure contains two crystallographically
independent sites of ruthenium atoms randomly occupied by the RuIII and RuIV cations. The superstructure with the doubled b parameter found for one of the samples under study using electron diffraction is caused, probably, by ordering of the Ru
cations in the rutile-like chains. The Na1− x
Ru2O4 compound exhibits temperature-independent paramagnetism with χ0 = 1.9·10−4 cm3 (mole of Ru−1).
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1655–1660, October, 2006. 相似文献
9.
Zhou DD Han K Zhang P Harding LB Davis MJ Skodje RT 《The journal of physical chemistry. A》2012,116(9):2089-2100
The HO(2) + HO(2) → H(2)O(2) + O(2) chemical reaction is studied using statistical rate theory in conjunction with high level ab initio electronic structure calculations. A new theoretical rate coefficient is generated that is appropriate for both high and low temperature regimes. The transition state region for the ground triplet potential energy surface is characterized using the CASPT2/CBS/aug-cc-pVTZ method with 14 active electrons and 10 active orbitals. The reaction is found to proceed through an intermediate complex bound by approximately 9.79 kcal/mol. There is no potential barrier in the entrance channel, although the free energy barrier was determined using a large Monte Carlo sampling of the HO(2) orientations. The inner (tight) transition state lies below the entrance threshold. It is found that this inner transition state exhibits two saddle points corresponding to torsional conformations of the complex. A unified treatment based on vibrational adiabatic theory is presented that permits the reaction to occur on an equal footing for any value of the torsional angle. The quantum tunneling is also reformulated based on this new approach. The rate coefficient obtained is in good agreement with low temperature experimental results but is significantly lower than the results of shock tube experiments for high temperatures. 相似文献
10.
Chun Gu Dr. Weiqiang Yu Hanqing Zhao Prof. Dr. Song Shi Dr. Penghua Che Prof. Dr. Jie Xu Prof. Dr. Jin Gao 《ChemCatChem》2024,16(2):e202301169
A series of porous silica were prepared by alkyl-trimethyl-ammonium bromide with different carbon chain lengths (PS-n, n corresponds to the carbon chain length). These templates carried out precise structure regulation of porous silica. The Ru particles supported on porous silica behaved in precisely controlled size according to the pore diameter. When used in the hydrogenolysis of biomass polyols, a higher methane yield was achieved over Ru/PS-16. This result can be explained by the higher C2/C3 over Ru/PS-16 than others. 相似文献
11.
Xuemin Chen Sue E. Gillespie John L. Oscarson Reed M. Izatt 《Journal of solution chemistry》1992,21(8):825-848
The phase equilibrium CO2(g)=CO2(aq) and the aqueous reactions CO
3
2–
+H+=HCO
3
–
, HCO
3
–
+H+=CO2(aq)+H2O, and Na++CO
3
2–
=NaCO
3
–
were studied from 225 to 325°C using a flow calorimetric technique. Heats of mixing of gaseous CO2 with liquid H2O and with aqueous NaOH solutions were measured at these temperatures. Log K, H, S, and Cp values were determined for these reactions from the heat of mixing data. Equations for these thermodynamic quantities valid at infinite dilution (I=0) and 12.4 MPa are given as a function of temperature from 225 to 325°C. The log K and H values agree well with literature values at these temperatures for the first and third reactions, but not for the second reaction. No previous results have been reported for the fourth reaction at high temperatures. The isocoulombic reaction principle is tested using the log K values determined in this study. This principle is found to be valid for the reactions where each charge on one side of the equation is balanced on the other side by a charge of the same sign and magnitude, but not for the reaction where two single negative charges (HCO
3
–
and OH–) are balanced by one double negative charge (CO
3
2–
).Presented at the Second International Symposium on Chemistry in High Temperature Water, Provo, UT, August 1991.Taken in part from the Ph.D. Dissertation of X. Chen, Brigham Young University, 1991. 相似文献
12.
The reaction of (NBu4)2[Pt(CN)4] with Cu(NO3)2·2.5H2O and bipy in stoichiometric ratio in methanol solution yields the 2-D polymer {Cu(bipy)Pt(CN)4}. The influence of water molecules and hydrogen bonding on the formation of a 2-D polymeric structure versus a tetranuclear cluster from Cu(bipy)Pt(CN)4 units is discussed. 相似文献
13.
The crystal of the title compound (C10H18N2O9SZn Mr= 407. 69) belongs to the hexagonal system, space group P65 with cell parameters: a= 11. 411(2), c=20. 908(4) A, V=2357.7(7)A 3, Z=6, Dc=1. 723g/cm3, F(000)=1260,μ(MoKα) =1. 743mm-1. The final R and wR factors are 0. 072 and 0. 178 respectively for 1335 observed reflections. In the structure, zinc ions are bridged by 4,4'-bipyridine to form infinite chains. The sheets containing parallel chains stack along a 65 screw axis to give a helical staircase motif. The helical structure is mainly controlled by the hydrogen bonds. 相似文献
14.
The reaction path, the dynamical properties along the reaction path and CVT rate constants are computed by the ab initio MO method, the reaction path Hamiltonian theory and the variational transition state theory. The results show that the effect of the electron correlation energy on activation barrier is large, the recrossing and tunneling effects exist in the reaction. 相似文献
15.
《Chemical physics letters》1985,118(5):530-533
The energy distribution of nascent OH(2Π, υ, J) produced in the reaction of O(1D) with H2S has been measured by laser-induced fluorescence. The rotational distributions in υ″ = 0 and υ″ = 1 are Boltzmannian with temperature parameters Tr″-0 = 2300 ± 100 K and Tr−-1 = 2650 ± 150 K. A population ratio N(υ″ = 1)/N(υ″ = 0) = 0.17 is observed. The product-state distribution over the different spin and A components is statistically within the experimental uncertainty of 20%. A comparison of the OH product populations from the title reaction with the well known OH yield from the O(1D)+H2O reaction shows that 25% of the reactive encounters follow the reaction channel which produces OH in υ″ = 0 and υ″ = 1. 相似文献
16.
H. Y. Zhang N. Ren L. Tian J. J. Zhang 《Journal of Thermal Analysis and Calorimetry》2009,98(2):401-408
The complexes of [Sm(o-MOBA)3bipy]2·H2O and [Sm(m-MOBA)3bipy]2·H2O (o(m)-MOBA = o(m)-methoxybenzoic acid, bipy-2,2′-bipyridine) have been synthesized and characterized by elemental analysis, IR, UV, XRD and molar conductance, respectively. The thermal decomposition processes of the two complexes were studied by means of TG–DTG and IR techniques. The thermal decomposition kinetics of them were investigated from analysis of the TG and DTG curves by jointly using advanced double equal-double steps method and Starink method. The kinetic parameters (activation energy E and pre-exponential factor A) and thermodynamic parameters (ΔH ≠ , ΔG ≠ and ΔS ≠) of the second-step decomposition process for the two complexes were obtained, respectively. 相似文献
17.
The oxidation reaction dynamics of the gas-phase yttrium atoms by oxygen molecules was studied under crossed-beam conditions. The product YO was detected using a time-of-flight mass spectrometer combined with laser single-photon ionization. An acceleration lens system designed for the ion-velocity mapping conditions, a two-dimensional (2-D) detector, and a time-slicing technique were used to obtain the velocity and angular distributions of the products. Two ionization wavelengths were used for the internal (vibrational and/or electronic) energy selective detection of YO. The single photon of the shorter wavelength (202.0 nm) can ionize all states of YO(X?(2)Σ, A'?(2)Δ, and A?(2)Π), while electronically excited YO(A' and A) are dominantly ionized at a longer wavelength (285.0 nm). Time-sliced images were converted to the velocity and angular distributions in the center-of-mass frame. The general features of the velocity distributions of YO, determined at two wavelengths, were well represented by those expected from the statistical energy disposal model. The forward-backward symmetry was also observed for two images. These results suggest that the reaction proceeds via long-lived intermediates, and that this mechanism is consistent with previous chemiluminescence/LIF studies. 相似文献
18.
Quasi-classical trajectory (QCT) calculations are employed for the reaction F + HO(0,0)→HF + O based on the adiabatic potential energy surface (PES) of the ground 3A″triplet state. The average rotational alignment factor P2(j′·k) as a function of collision energy and the four polarization dependent generalized differential cross sections have been calculated in the center-of-mass (CM) frame, separately. The distribution P(θr) of the angle between k and j′, the distribution P(θr) of dihedral angle denoting k-k′-j′ correlation, and the angular distribution P(θr, Φr) of product rotational vectors in the form of polar plots are calculated as well. The effect of Heavy-Light-Heavy (HLH) mass combination and atom F's relatively strong absorbability to charges on the alignment and the orientation of product molecule HF rotational angular momentum vectors j′ is revealed. 相似文献
19.
《Solid State Sciences》2001,3(3):309-319
Single crystals of two lanthanide complexes, presenting similar formula Ln(H2O)x(C2O4)2 · NH4 with Ln=La, x=0 and Ln=Gd, x=1, have been prepared, in closed system at 200 °C. The gadolinium complex is bi-dimensional. A layer is built by the packing of the basic unit, [Gd(C2O4)]4. The gadolinium atoms are related only by bischelating oxalate ligands, the ammonium ion and the water molecule (bound to the gadolinium atom) are localized into the interlayer space. The lanthanum complex is tri-dimensional. The basic building unit remains approximately the same and the packing of these units form a layer. However, within these units, the lanthanum atoms are related by either an oxalate ligand or an edge. Moreover, an oxalate ligand assumes the connection between the layers. The ammonium ion is localized into two sets of intersecting channels. Pure phase of the gadolinium complex has been prepared at 100 °C and extended to some lanthanide elements, Eu…Yb. As the size of the lanthanide ionic radius is decreasing, it is noticeable that the a unit–cell constant follows an expansion pattern while the others two follow an usual contraction one. The thermal behavior of this family shows that the anhydrous compounds are obtained and that some water molecule is sorbed during the cooling. Thus, the anhydrous compounds present a relatively open-framework with some small micropores. 相似文献
20.
Hassan Talaat Ali H. Moussa M. Shalaby El-Wallid S. Sedik M. Tag El-Din Kamal 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2013,87(3):454-460
We apply the time-dependent theory to the collinear exchange reaction F + CH4 → FCH3 + H. We have performed detailed calculations on two-dimensional potential surfaces representing the ground electronic potentials of the collinear F + CH4 → FCH3 + H reaction, at incident energies. Transmission coefficients range from zero to unity, depending upon the incident energy. Normal modes of vibrations are displayed along the reaction path. 相似文献