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1.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1994,50(7):1277-1285
A full vibrational spectroscopic study of sodium hypophosphite, sodium phosphite and their deuteriated analogues has been made. The vibrations characteristic of the hypophosphite anion have been assigned and the presence of a previously unreported band has been established for the Raman spectrum of the aqueous solution. The first Raman study of deuteriated sodium phosphite has been undertaken and a full vibrational assignment is given. 相似文献
2.
3.
Nobumitsu Honjou 《Journal of Molecular Structure》2010,939(1-3):59-64
Molecular vibrations and electronic structure of the X2Σ+, B2Σ+, D2Σ+, and F2Σ+ states of AlO are studied by carrying out ab initio configuration interaction calculations and molecular vibration calculations using accurate potential energy functions. An avoided crossing between the D2Σ+ and F2Σ+ potential energy curves occurs in the neighborhood of 4.0 a0 and results in irregular vibrational levels of the D and F2Σ+ states. The vibrational constants for the F2Σ+ state are predicted from the vibrational levels not involved in the irregularity. Configuration mixing is important in describing the B, D, and F2Σ+ states. The F2Σ+ state at and around its well minimum and the D and F2Σ+ states in the avoided crossing region are characterized in terms of their main configurations and dipole moment functions. 相似文献
4.
M. Natália D. S. Cordeiro Roberto Cammi José A. N. F. Gomes Jacopo Tomasi 《Theoretical chemistry accounts》1992,82(3-4):165-187
The interaction energyE of the systems Cu+-H2O and Cl–-H2O has been computed over a wide range of distances and orientations with the MINI-1 basis set in the SCF approximation. The interaction energy has been decomposed according to the Kitaura-Morokuma scheme, with and without counterpoise (CP) corrections to the basis set superposition error. The importance of this correction is analysed by its effect upon Monte Carlo calculations of the Cu+-water and Cl–-water systems, using two-body potentials without and with CP corrections. The effect of CP corrections on theE analysis is similar to that found in other systems of analogous composition (of the general type ion plus neutral ligands), but with significant differences in the details. The effect of the CP corrections to the interaction potential, and then on the results of the Monte Carlo simulations, is small for the Cu+ ion, but remarkable for the Cl– ion. 相似文献
5.
V. B. Kobychev N. M. Vitkovskaya N. S. Klyba B. A. Trofimov 《Journal of Structural Chemistry》2004,45(1):5-11
Ab initio (MP4/6-31G*//RHF/6-31+G*) calculations have been performed to study the acetylene–allene rearrangement in X–CH2–CCH propargyl systems, where X = ethenyl, E-1-butadienyl, 2-pyrrolyl, 2-furanyl, and 2-thienyl. The spatial and electronic structures, as well as the relative stability, of the initial and final acetylene structures and the corresponding allenes are examined. Migration of the triple bond from the terminal position into the chain, including the stage of allene structure formation, is shown to be thermodynamically favorable for the whole series of compounds. The propargyl substituents of heterocycles isomerize as readily as open diene systems. The differences in the isomerization energies in the series of allenyl- and 1-propynyl-substituted pyrrole, furan, and thiophene are mainly due to the differences in the nature of long-range interactions between heteroatoms and the tricarbon system. 相似文献
6.
I. K. Larin N. A. Messineva A. I. Spasskii E. M. Trofimova L. E. Turkin 《Kinetics and Catalysis》2000,41(4):437-443
The reactions of iodine monoxide (IO•) with sulfur-containing compounds, which are important for the atmospheric chemistry, are studied. An attempt is made to
distinguish between the heterogeneous and homogeneous reaction pathways. It is shown that, under the experimental conditions,
the reactions proceed on the wall and generate iodine atoms into the gas phase. It is found that, at room temperature, the
rate constants for the gas-phase reactions of IO• with (CH3)2S and H2S are lower than 2.5 × 10−14 and 8.0 × 10−14 cm3 molecule−1 s−1, respectively; the rate constant for the gas-phase reaction of iodine monoxide with SO2 ≤ 5.6 × 10−15 cm3 molecule−1 s−1. 相似文献
7.
M. Horn S. Seeger R. Oswald P. Botschwina 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1996,36(3-4):293-299
The vibrational structure of the first band of the photoelectron (PE) spectrum of HO 2 ? and DO 2 ? has been calculated on the basis of (slightly modified) ab initio potentials. The best agreement with the experimental spectrum of HO 2 ? is obtained for a vibrational temperature of ca. 600 K. “Peak D”, which has been under debate in earlier work, is composed of two transitions, with the “hot” transition 3 1 1 being more intense than the adiabatic transition. Since thev 2 bending mode of DO2 has significant OO stretching character, the vibrational structure of the PE spectrum of DO 2 ? is more complex than that of HO 2 ? . Large-scale RCCSD(T) calculations of the equilibrium electron affinity of HO2 yield 1.058 eV which agrees with the experimental value of 1.044 ± 0.020 eV. 相似文献
8.
Farid I. El-Dossoki 《Journal of solution chemistry》2010,39(9):1311-1326
The effect of the charge and the nature of both the cations and the anions of some electrolytic salts: sodium fluoride (NaF),
potassium fluoride (KF), sodium bromide (NaBr), potassium bromide (KBr), sodium iodide (NaI), potassium iodide (KI), sodium
sulfate (Na2SO4), potassium sulfate (K2SO4), calcium chloride (CaCl2), and barium chloride (BaCl2), on the solubility of zwitterionic amino acids (glycine, DL-alanine, DL-valine, and DL-serine) in aqueous solutions at 298.15 K
are studied and discussed. A salting-in effect is observed for all amino acids under investigation with all electrolytes used
in the present study, except for DL-alanine and DL-valine in aqueous solutions containing sodium fluoride where a salting-out
effect was observed. The orders of the effect of the nature and the charge of both the anions and the cations are: F- < Cl- < Br- < I- < NO3- < SO42-\mathrm{F}^{-}<{}\mathrm{Cl}^{-}<{}\mathrm{Br}^{-}<{}\mathrm{I}^{-}<\mathrm{NO}_{3}^{-}<{}\mathrm{SO}_{4}^{2-} with both sodium and potassium cations; Na+<K+<Ca2+<Ba2+ with chloride anion. 相似文献
9.
Effect of TiO2 Support on the Composition, Morphology and Catalytic Property of the NiB Amorphous Alloy Catalyst 总被引:1,自引:0,他引:1
LaiJunWANG MingHuiZHANG WeiLI KeYiTAO 《中国化学快报》2004,15(11):1357-1360
Both the unsupported and supported NiB amorphous alloy catalysts (NiB and NiB/TiO2)were prepared by the chemical reduction method. Their catalytic activities were tested by thehydrogenation of sulfolene. The interactions between the NiB alloy and TiO2 were discussed forthe first time by using XRD, ICP, SEM and TEM. 相似文献
10.
SinceHutton]developedanovelr0utet0preparationofthe2-alkoxycarbonylalkyltintrichIorides,R'OCOCHRCH,SnCI,(l),lhavereceivedconsiderableattenti0nbecauseofthevarietyofcoordinationgeometriesaboutthetinatom.2-'Previ0usly,wehadre-portedtheadducts0flwithneutraIdonorssuchasDMSO,HMPA,bpyandphen.'-'Inthispaper,wereportthesynthesis0fthecomplexes0flwithnegativebivaIentligandderivedfr0m2-salicylideneamin0phenop(H2L),R'OCOCHRCH,SnClL(R=H,Me,R'=Me,Et,n-Pr,Allyl,n-Bu),andthecrystaIstructureof… 相似文献
11.
John L. Oscarson Sue E. Gillespie Xuemin Chen Paul C. Schuck Reed M. Izatt 《Journal of solution chemistry》2001,30(1):31-53
Dilution enthalpies, measured using isothermal flow calorimetry, are reported for aqueous solutions of BaCl2 at 300°C and 11.0 MPa, MgCl2, CaCl2, and BaCl2 at 325°C and 14.8 MPa, and at 350°C and 17.6 MPa. Previously collected dilution enthalpies for aqueous solutions of MgCl2 and CaCl2 at 300°C and 10.3 MPa and for aqueous solutions of HCl at 250, 275, and 300°C at 10.3 MPa and 320°C at 12.8 MPa were included with the new data at 300°C and 11.0 MPa and at 350°C and 17.6 MPa when fitting the Pitzer parameters. The concentration range of the chloride solutions was 0.5 to 0.02 molal. Parameters for the Pitzer excess Gibbs ion–interaction equation were determined from the fits of the experimental heat data. Equilibrium constants, enthalpy changes, entropy changes, and heat-capacity changes for the association of alkaline earth metal ions and H+ with chloride ion were estimated from the heat data. For all systems, the enthalpy and entropy changes are positive and show accelerating increases with temperature. The resulting equilibrium constants show significant, but smaller, increases with temperature. 相似文献
12.
《Journal of solid state chemistry》1986,64(3):365-371
Members of the systems Co1−xRhxS2 (0 ≤ x ≤ 0.6) were prepared, and their crystallographic and magnetic properties studied. The observed ferromagnetic moments for compositions where x ≤ 0.2 indicate a ferromagnetic alignment between Co(3d7) and Rh(4d7) electrons. This is the first observation of localized behavior of 4d electrons in the pyrite structure. Members of the systems Co1−xRuxS2 (0 ≤ x ≤ 1) and Rh1−xRuxS2 (0.5 ≤ x ≤ 1) were also prepared and their crystallographic and magnetic properties studied. From comparison with the Co1−xRhxS2 system, it appears that the 4d electrons of Rh(4d7) are localized in the presence of Co(3d7) but are delocalized in the presence of Ru(4d6). The magnetic susceptibility of the Co1−xRuxS2 system is sensitive to the homogeneity of the products and indicates that Ru(4d6) behaves as a diamagnetic ion. 相似文献
13.
George Priya Doss C B. Rajith Chiranjib Chakraborty 《Applied biochemistry and biotechnology》2013,170(8):1853-1870
Fibroblast growth factor receptor 2 (FGFR2) controls a wide range of biological functions by regulating the cellular proliferation, survival, migration and differentiation. A growing body of preclinical data demonstrated that deregulation of the FGFR signalling through genetic modification was observed in various types of cancers. However, the extent to which genetic modifications interfere with gene regulation and their involvement in cancer susceptibility remains largely unknown. In this work, we performed in silico profiling of harmful non-synonymous single nucleotide polymorphisms (SNPs) in the protein kinase domain of FGFR2. Tolerance index, position-specific independent count score, change in free energy score (ΔΔG), Eris and FoldX indicated that seven mutations were found to be deleterious and may alter the protein function and structure. Furthermore, based on physico-chemical properties, two mutations K659N and R747H were found to be most deleterious in protein kinase domain and taken for further structural analysis. Docking study showed a complete loss of binding affinity followed by interference in hydrogen bonding and surrounding residues due to K659N and R747H mutations. In order to elucidate the mechanism behind the impact of mutation that can generate a ripple effect throughout the protein structure and ultimately affect the function, in-depth molecular dynamics simulation and principal component analysis were performed. The obtained results indicate that K659N and R747H mutations have a distinct effect on the dynamic behaviour of FGFR2 protein. Our strategy may be helpful for understanding SNP effects on proteins with function and their role in human genetic diseases and for the development of novel pharmacological strategies. 相似文献
14.
C. A. Strydom E. M. Groenewald J. H. Potgieter 《Journal of Thermal Analysis and Calorimetry》1997,49(3):1501-1507
Using a heating rate of 2°C min–1, CaS reacts with oxygen in air from 700°C to form CaSO4, with a complete conversion at 1100°C. Synthesis of CaS from the reaction between CaSO4 containing compounds and carbon compounds in air would not be possible, as the carbon reacts from 600°C with oxygen in the air to give CO2. Heating stoichiometric amounts of carbon and pure CaSO4, synthetic gypsum or phosphogypsum in a nitrogen atmosphere, results in the formation of CaS from 850°C. Using a heating rate of 10°C min–1, the formation of CaS is completed at 1080°C. Addition of 5% Fe2O3 as a catalyst lowers the starting temperature of the reaction to 750°C. Activation energy values at different fraction reaction values () differ between 340 and 400 kJ mol–1. The relationship between the activation energy values and conversion () indicates that the reaction proceeds via multiple steps. 相似文献
15.
《Journal of solid state chemistry》1987,67(2):291-296
Ytterbium dichloride was prepared in pure form by the oxidation of elemental ytterbium by ZnCl2 with subsequent removal of the zinc impurities by sublimation. Ytterbium dibromide in the orthorhombic SrI2-type structural form was prepared in a sealed tantalum container by reduction of the tribromide with elemental ytterbium at a temperature not exceeding 960°C for 15 min. The dihalides, mixed intimately in appropriate molar ratios in a glove-box and contained in pyrolytic graphite boats, were melted under vacuum. These two halides form a solid solution with the SrI2-type structure. Lattice parameters are reported as a function of composition. 相似文献
16.
Tatiana Trejos Robert Koons Stefan Becker Ted Berman JoAnn Buscaglia Marc Duecking Tiffany Eckert-Lumsdon Troy Ernst Christopher Hanlon Alex Heydon Kim Mooney Randall Nelson Kristine Olsson Christopher Palenik Edward Chip Pollock David Rudell Scott Ryland Anamary Tarifa Melissa Valadez Peter Weis Jose Almirall 《Analytical and bioanalytical chemistry》2013,405(16):5393-5409
Elemental analysis of glass was conducted by 16 forensic science laboratories, providing a direct comparison between three analytical methods [micro-x-ray fluorescence spectroscopy (μ-XRF), solution analysis using inductively coupled plasma mass spectrometry (ICP-MS), and laser ablation inductively coupled plasma mass spectrometry]. Interlaboratory studies using glass standard reference materials and other glass samples were designed to (a) evaluate the analytical performance between different laboratories using the same method, (b) evaluate the analytical performance of the different methods, (c) evaluate the capabilities of the methods to correctly associate glass that originated from the same source and to correctly discriminate glass samples that do not share the same source, and (d) standardize the methods of analysis and interpretation of results. Reference materials NIST 612, NIST 1831, FGS 1, and FGS 2 were employed to cross-validate these sensitive techniques and to optimize and standardize the analytical protocols. The resulting figures of merit for the ICP-MS methods include repeatability better than 5 % RSD, reproducibility between laboratories better than 10 % RSD, bias better than 10 %, and limits of detection between 0.03 and 9 μg g?1 for the majority of the elements monitored. The figures of merit for the μ-XRF methods include repeatability better than 11 % RSD, reproducibility between laboratories after normalization of the data better than 16 % RSD, and limits of detection between 5.8 and 7,400 μg g?1. The results from this study also compare the analytical performance of different forensic science laboratories conducting elemental analysis of glass evidence fragments using the three analytical methods. Figure
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17.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1987,43(3):395-400
The i.r. and Raman spectra of CuCl2·2H2O and K2CuCl4·2H2O and of deuterated samples of these compounds are presented in the range 50–1700 cm−1 at liquid helium, liquid nitrogen, and ambient temperatures. The spectra obtained are discussed and compared with the literature data in terms of both bonding structure of the water molecules and vibrational modes, assignment, intermolecular coupling, and combination bands of the H2O, HDO, and D2O librations. The i.r. and Raman bands of the librational modes of CuCl2·2H2O are very broad even at liquid helium temperature indicating orientational disorder of the water molecules. 相似文献
18.
In this work, the influence of metallic dopant addition in 10 wt % Ni/γ-Al2O3 catalyst on the material physico-chemical properties and catalytic activity for the toluene steam reforming was studied. Seventeen doped Ni/γ-Al2O3 catalysts were synthesized by the sol–gel process. The aim of this study was to determine which elements were the most suitable for the doping of 10 wt % Ni/γ-Al2O3 catalysts. The influence of the dopants was studied through different physico-chemical techniques. It appeared that some dopants showed lower catalytic performances due to high carbon deactivation. On the contrary, some dopants increased the resistance to coking while also improving the catalytic activity. Different mechanisms were proposed to explain these modifications of catalytic behavior. Among all doped Ni/γ-Al2O3 catalysts, the samples that combined Mn + Mo or Co + Mo dopants showed the best catalytic performances at 650 °C. Both samples showed high toluene reforming activity and low amounts of carbon deposit. 相似文献
19.
Dahlstrand C Rosenberg M Kilså K Ottosson H 《The journal of physical chemistry. A》2012,116(20):5008-5017
The singlet ground states and lowest triplet states of penta- and heptafulvene, their benzannulated derivatives, as well as the lowest quintet states of pentaheptafulvalenes, either the parent compound or compounds in which the two rings are intercepted by either an alkynyl or a phenyl segment, were investigated at the (U)OLYP/6-311G(d,p) density functional theory level. The influence of (anti)aromaticity was analyzed by the structure-based aromaticity index HOMA, the harmonic oscillator model of aromaticity. The extent of (anti)aromatic character was also evaluated in terms of the π-electron (de)localization as measured by the π component of the electron localization function (ELF(π)). The natural atomic orbital (NAO) occupancies were calculated in order to evaluate the degree of π-electron shift caused by the opposing electron-counting rules for aromaticity in the electronic ground state (S(0); Hückel's rule) and the first ππ* excited triplet state (T(1); Baird's rule). Pentaheptafulvalene (5) shows a shift of 0.5 π electrons from the 5-ring to the 7-ring when going from the S(0) state to the lowest quintet state (Qu(1)). The pentaheptafulvalene 5 and [5.6.7]quinarene 7 were also investigated in their 90° twisted conformations. From our study it is apparent that excitation localization in fulvalenes, but not in fulvenes, to a substantial degree is determined by aromaticity localization to triplet biradical 4n π-electron cycles. Isolated benzene rings in these compounds tend to remain as closed-shell 6π-electron cycles. 相似文献
20.
Structural Chemistry - The contents of issues 1 and 2 of Structural Chemistry from the calendar year 2018 are summarized in the present review. A brief thermochemical commentary and recommendations... 相似文献