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1.
V. D. Kiselev E. A. Kashaeva M. S. Shihab M. D. Medvedeva A. I. Konovalov 《Russian Chemical Bulletin》2000,49(6):1040-1044
The partial molar volumes (V) and the enthalpies of dissolution (Δdis
H) for tetracyanoethylene, cyclopentadiene, and their Diels—Alder adduct were determined at 25°C. Eleven solvents of the π-
and n-donor type were used. The use of alkylbenzenes as solvents for tetracyanoethylene induces pronounced changes in the
enthalpy of dissolution (up to 26 kJ mol−1) and in the partial molar volume (up to 11 cm3 mol−1), whereas these parameters for the adduct change slightly. TheV and Δdis
H values for cyclopentadiene virtually do not depend on the nature of the solvent. In the case of tetracyanoethylene and the
adduct in n-donor solvents, considerable variations of theV and Δdis
H values are observed; they are not linear functions of the change in the partial molar volume of the adduct. Therefore, the
reaction volumes in acetonitrile (−40.69) and ethyl acetate (−45.56) differ sharply from those ino-xylene (−24.28) and mesitylene (−21.76 cm3 mol−1).
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1046–1050, June, 2000. 相似文献
2.
V. M. Pinchuk E. S. Kotlyarova N. V. Parkhomenko P. N. Tsybulev 《Journal of Structural Chemistry》1996,37(4):544-556
The studies concerned with the oxidation of carbon monoxide on the nickel surface are reviewed. The Eley-Rideal (ER) collision
and Langmuir-Hinshelwood (LH) adsorption mechanisms of the oxidation are analyzed. Calculations of the activation barriers
of the oxidation of carbon monoxide on the Ni (111), (100), and (110) faces were performed for the first time and involved
optimization of the reaction paths by the collision and adsorption mechanisms. It is shown that on the Ni (111) and (110)
faces the ER collision mechanism of the reaction is preferable with the activation barriers ΔE
dis
O
2=62 kJ/mole and ΔE
trans
O
A21F50012x=25 kJ/mole for Ni (111) and ΔE
dis
O
2=72 kJ/mole and ΔE
trans
O
2=20 kJ/mole for Ni (110); on the Ni (100) face, the LH adsorption mechanism with the activation barriers ΔE
dis
O
2=75 kJ/mole and ΔE
trans
O
2=42 kJ/mole is favored. Analysis of the potential barriers for the catalytic oxidation of carbon monoxide on the Ni surfaces
suggests the LH mechanism to be preferential, although insignificant differences in the activation barries can lead to the
oscillatory reaction mechanism, which is confirmed experimentally. The calculations were performed by the LCAO MO SCF method
in the MINDO/3 approximation.
Kiev Polytechnical Institute. Translated fromZhurnal Struktumoi Khimii, Vol. 37, No. 4, pp. 628–645, July–August, 1996.
Translated by I. Izvekova 相似文献
3.
The existence of a hydrogen bond in which a methyl group of the (MeOH)2H+ ion acts as a proton donor is examined. The fundamental vibration frequencies of this ion were calculated for different numbers
and strengths of CH…O bonds. The atomic charges in neutral ((MeOH)
n
,n=1–4) and protonated ((MeOH)
m
H+,m=2–6) associates of methanol molecules were also calculated. The experimentally observed decrease in the v(CH) vibration frequencies
of the (MeOH)2H+ ion to 2890 cm−1 and 2760 cm−1 is attributable to the fact that each methyl group of the ion is involved in formation of two CH…O bonds with strength of
−12.5 kJ mol−1. The proton-donating ability of the CH bond depends on the charge on its H atom; however, it does not correlate with the
dipole moment of this bond.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 306–312, February, 1999. 相似文献
4.
M. V. Muftakhov R. V. Khatymov V. A. Mazunov V. N. Odinokov I. V. Galyautdinov 《Russian Chemical Bulletin》2000,49(4):713-716
The peculiarities of dissociative electron capture by 20-hydroxyecdysone molecules with the formation of fragment negative
ions were studied. In the region of high electron energies (5–10 eV), processes of skeleton bond rupture are accompanied by
the elimination of H2O and H2 molecules. In the region of thermal energies of electrons (≈0 eV), the mass spectrum is formed mainly by the [M−nH2O].− (n=1–3) and [M−H2−nH2O].− (n=0−3) ions that are generated exclusively by the rearrangement.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 709–712, April, 2000. 相似文献
5.
A. V. Nemukhin V. V. Togonidze V. M. Kovba R. Yu. Orlov 《Journal of Structural Chemistry》1998,39(3):372-375
Equilibrium geometrical configurations and harmonic vibration frequencies are determined by ab initio quantum chemical methods
using the relativistic effective potential for gold in AuSH, Au(SH)
2
−
, Au(SH)(H2S), AuSH·(H2O)m, and Au(SH)
2
−
·(H2O)4 molecular systems. Solvation shifts in the vibrational spectra of the gold thiocomplexes are estimated by comparing the data
between anhydrous and aqueous complexes.
M. V. Lomonosov Moscow State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 39, No. 3, pp. 460–463, May–June, 1998.
This work was supported by RFFR grant No. 95-03-08205. 相似文献
6.
V. P. Novikov S. A. Tarasenko S. Samdal L. V. Vilkov 《Journal of Structural Chemistry》2000,41(2):217-230
The geometrical parameters for 1,1-dimethylsilacyclobiitane and 1,1,3,3-tetramethyl-13-disilacyclobutune are detemiined by
gas phase electron diffraction analysis using a dynamic model, which considers ring inversion as a large-amplitude motion.
The structural and potential function parameters were refined with allowance for molecular geometry relaxation estimated by
quantum chemical calculations with an HF/6-311G** basis. The potential function of 1,1-dim ethylsilacyclobutane is represented
as V(ϕ) = V0[(ϕ/ϕe)2 − 1]2 with V0 = 1.3 ± 1.2 kcallmole and ϕe = 29.7±4.5°, where ϕ is the ring puckering angle. A more reliable estimate for the height of the barrier (V0 = 0.56 kcallmole) was obtained by solving the one-dimensional quantum vibrational problem and by fitting the frequency of
the 0 →2 transition to the experimental value. For 1,1,3,3-tetram ethyl-1,3-disilacyclobutane, the potential function is adequately
represented bx V(ϕ) = Aϕ2, where A = (4.9 ± 1.8) · 10−4 kcall(mole · deg2) with a minimum coiresponding to a planar ring conformation with ϕ = 0°. The calculated structural parameters are compared
with the data for related compounds.
Translated fromZhumal Struktumoi Khimii. Vol. 41, No. 2, pp. 269–284, March–April, 2000 相似文献
7.
N. V. Platonova Yu. O. Punin V. D. Franke E. N. Kotelnikova 《Journal of Structural Chemistry》1994,35(5):634-641
In the ammonium chloride crystallization region of the NH4Cl−CuCl2−H2O−CH3ON system, cocrystallization of the impurity with the main substance occurs by epitaxial adsorption of complexes of varying
composition. In NH4Cl crystals, the Cu2+ impurity forms oriented interlayers (ingrowths) simultaneously at the macro-and microlevels. The ratio between the two trapping
forms depends on the growth conditions.
St. Petersburg State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 35, No. 5, pp. 70–78, September–October, 1994.
Translated by L. Smolima 相似文献
8.
The method of Wiberg and Boyd was used to determine the pathways for the interconversion of the 3,4-anhydropyranose ring in methyl-2,6-di-O-acetyl-3,4-anhydro--DL (6,6-2H2) derivatives of talopyranoside (1) and galactopyranoside (2). Stationary points were found on the potential surface. The E0+1H0 and0H1def conformations are global minima in 1. Three local minima are found near the boat conformation B2.5 and2.5B. Two saddle points are also found near these conformations. The1H0 and0H1def conformations are also global minima in 2. Only one local minimum and two saddle points were found, as in the case of 1, near the B2.5 and2.5B conformations. The interconversion barriers in 1 and 2 were calculated. The physical factors affecting the ring conformation in these compounds were discussed.Institute of Physics, Belarus Academy of Sciences. Translated from Zhurnal Strukturnoi Khimii, Vol. 34, No. 2, pp. 112–118, March–April, 1993. 相似文献
9.
Prithwiraj Byabartta 《Transition Metal Chemistry》2007,32(8):1007-1011
Reaction of [Au(C6F5)(tht)2Cl](OTf) with RaaiR′ in CH2Cl2 medium leads to [Au(C6F5)(RaaiR′)Cl](OTf) [RaaiR′ = p-R–C6H4–N=N–C3H2–NN-1-R′, (1–3), abbreviated as N,N′-chelator, where N(imidazole) and N(azo) represent N and N′, respectively; R = H (a), Me (b), Cl (c) and R′ = Me (1), CH2CH3
(2), CH2Ph (3), tht is tetrahydrothiophen]. The maximum molecular peak of [Au(C6F5)(MeaaiMe)Cl] is observed at m/z 599.51 (100 %) in the FAB mass spectrum. Ir spectra of the complexes show –C=N– and –N=N– stretching near at 1590 and 1370 cm−1 and near at 1510, 955, 800 cm−1 due to the presence of pentafluorophenyl ring. The 1H-NMR spectral measurements suggest methylene, –CH2–, in RaaiEt gives a complex AB type multiplet while in RaaiCH2Ph shows AB type quartets. 13C-NMR spectrum of complexes confirm the molecular skeleton. In the 1H-1H-COSY spectrum as well as contour peaks in the 1H-13C HMQC spectrum for the present complexes, assign the solution structure and stereoretentive conformation. The electrochemistry
gives the ligand reduction peaks. 相似文献
10.
Y. Y. Di Z. C. Tan L. W. Li S. L. Gao L. X. Sun 《Journal of Thermal Analysis and Calorimetry》2007,87(2):545-551
Low-temperature heat capacities of a solid
complex Zn(Val)SO4·H2O(s) were measured by a precision automated adiabatic
calorimeter over the temperature range between 78 and 373 K. The initial dehydration
temperature of the coordination compound was determined to be, T
D=327.05
K, by analysis of the heat-capacity curve. The experimental values of molar
heat capacities were fitted to a polynomial equation of heat capacities (C
p,m) with the reduced temperatures
(x), [x=f (T)], by least
square method. The polynomial fitted values of the molar heat capacities and
fundamental thermodynamic functions of the complex relative to the standard
reference temperature 298.15 K were given with the interval of 5 K.
Enthalpies of dissolution of the [ZnSO4·7H2O(s)+Val(s)] (Δsol
H
m,l
0)
and the Zn(Val)SO4·H2O(s) (Δsol
H
m,2
0) in 100.00 mL of 2 mol dm–3 HCl(aq) at T=298.15
K were determined to be, Δsol
H
m,l
0=(94.588±0.025) kJ mol–1 and Δsol
H
m,2
0=–(46.118±0.055)
kJ mol–1, by means of a homemade isoperibol
solution–reaction calorimeter. The standard molar enthalpy of formation
of the compound was determined as: Δf
H
m
0
(Zn(Val)SO4·H2O(s), 298.15 K)=–(1850.97±1.92) kJ mol–1,
from the enthalpies of dissolution and other auxiliary thermodynamic data
through a Hess thermochemical cycle. Furthermore, the reliability of the Hess
thermochemical cycle was verified by comparing UV/Vis spectra and the refractive
indexes of solution A (from dissolution of the [ZnSO4·7H2O(s)+Val(s)] mixture
in 2 mol dm–3 hydrochloric acid) and solution
A’ (from dissolution of the complex Zn(Val)SO4·H2O(s) in 2 mol dm–3
hydrochloric acid). 相似文献
11.
M. G. Myskiv E. A. Goreshnik V. K. Pecharskii V. V. Oljinik 《Journal of Structural Chemistry》1994,35(1):82-86
We have carried out synthesis and X-ray structural study (DARCH, MoKα radiation, graphite monochromator, ϕ/2ϕ, scan mode, 2ϕ<-65°) of the CuNo3·C6H11N π-complex (a=14.346(6), c=16.719(7) δA, space group I41/a, and Z=16). The bifunctional (bridge and chelate) tridentate molecule of diallylamine cross-links the inorganic component
into infinite spirals oriented along the axes 41 and 43. The mainly covalent character of the Cu+...No
3
-
bond affects the hydrogen bond strength and the efficiency of the metal-olefin interaction.
I. Franko Lvov State University. Translated fromZhumal Strukturmoi Khimii, Vol. 35, No. 1, pp. 90–94, January–February, 1994.
Translated by T. Yudanova 相似文献
12.
S. V. Goryainov 《Journal of Structural Chemistry》1996,37(1):58-64
This paper reports on the results of temperature studies (20–880°C) of the IR absorption spectra of dioptase crystals in the
range 50–4000 cm−1. During the dehydration of dioptase the state of water changes as follows: (1) initial state, (2) intermediate state with
damped external vibrations of H2O, (3) isolated water molecules with new hydrogen bonds, (4) formation of hydroxyls. The bands of the external virations of
H2O (1) vanish in state (2) because of the formation of vacancies in the six-membered water rings. The frequencies of the translation
vibrations of 6H2O in initial dioptase are close to those in liquid water: 169–170 and 277–290 cm−1. A factor-group analysis of the dioptase vibrations in the space group C
3i
2
is performed. All IR active vibrations 23Au+23Eu are described. The thirty five bands observed in the IR spectra are assigned. The dehydration-induced deformations of the
silicate rings are determined from the shifts of the vibrational bands of Si6O18.
Institute of Mineralogy and Petrography, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 1, pp. 68–74, January–February, 1996.
Translated by I. Izvekova 相似文献
13.
I. A. Poroshina N. P. Kotsupalo L. T. Menzheres V. P. Isupov 《Journal of Structural Chemistry》1994,35(5):709-719
Crystallochemical features of anion (Cl−, Br−, I−, NO
3
−
, CO
3
2−
, SO
4
2−
) varieties of the aluminum and lithium hydroxide were studied by using the aluminum and lithium binary hydroxide (LiOH·2Al(OH)3·2H2O) model in space group P63cm with the tetrahedral coordination of lithium. Atomic coordinates corresponding to the lowered lattice symmetry were refined.
Institute of Solid State Chemistry and Processing of Mineral Raw Materials, Siberian Branch, Russian Academy of Sciences.
Novosibirsk State Pedagogical University. Translated fromZhurnal Struktumoi Khimii, Vol. 35, No. 5, pp. 158–170, September–October, 1994.
Translated by T. Yudanova 相似文献
14.
Yu. Yu. Rusakov L. B. Krivdin N. V. Istomina E. Yu. Schmidt A. I. Mikhaleva 《Chemistry of Heterocyclic Compounds》2009,45(1):28-34
A conformational analysis of N-vinyl-2-phenylpyrrole was undertaken according to the results from experimental measurements
and nonempirical quantum-chemical calculation of the high-level 13C–1H and 13C–13C spin-spin coupling constants. Angular relationships were established in the direct and vicinal J
C,C and J
C,H constants in the N-vinylpyrrole fragment, making it possible to use them in stereochemical investigations of the vinyl derivatives
of pyrrole.
Dedicated to Boris Aleksandrovich Trofimov on his 70th jubilee.
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 35–42, January, 2009. 相似文献
15.
V. N. Kirichenko L. A. Glinskaya R. F. Klevtsova T. G. Leonova S. V. Larionov 《Journal of Structural Chemistry》1994,35(2):242-247
We have synthesized high-spin mixed-ligand Mn2+ complexes Mn(S2COR)2L where R=i−C3H7, i−C4H9; [L=1,10-phenanthroline (Phen), 2,2′-bipyridyl (2,2′-Bipy), 4,4′-bipyridyl (4,4′-Bipy)]. As solids, the compounds are stable
to oxidation by atmospheric oxygen. An X-ray structural study of the [Mn(S2COC3H7−i)2(2,2′-Bipy)] complex was carried out. The structure is composed of discrete monomeric molecules. The corrdination polyhedron
of the Mn atom is a distorted [4S+2N] octahedron. The molecules are bonded by van der Waals interactions.
Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 35, No. 2, pp. 106–111, March–April, 1994.
Translated by T. Yudanova 相似文献
16.
A. G. Mustafin M. A. Petrova R. R. Gataullin L. V. Spirikhin A. A. Fatykhov I. B. Abdrakhmanov L. F. Chertanova G. A. Tolstikov 《Russian Chemical Bulletin》1998,47(7):1340-1342
The molecular and crystal structure of 1-β-d-xylofuranosyluracil hydrate was established by X-ray diffraction analysis. The mutual arrangement of the xylofuranose fragment
and the nucleic base corresponds to the anti conformation. The furanose ring adopts a C-envelope conformation. The structure
of the nucleoside in a DMSO-d6 solution has been determined by1H NMR spectroscopy.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1378–1380, July, 1998. 相似文献
17.
Bikshandarkoil R. Srinivasan Christian Näther Sunder N. Dhuri Wolfgang Bensch 《Monatshefte für Chemie / Chemical Monthly》2006,137(4):397-411
Summary. Four new organic ammonium tetrathiotungstates (N–Me–enH2)[WS4] (1), (N,N′-dm-1,3-pnH2)[WS4] (2), (1,4-bnH2)[WS4] (3), and (mipaH)2[WS4] (4), (N–Me–enH2 = N-methylethylenediammonium, N,N′-dm-1,3-pnH2 = N,N′-dimethyl-1,3-propanediammonium, 1,4-bnH2 = 1,4-butanediammonium, and mipaH = monoisopropylammonium) were synthesized by the base promoted cation exchange reaction and characterized by elemental analysis,
infrared, Raman, UV-Vis and 1H NMR spectroscopy as well as single crystal X-ray crystallography. The structures of 1–4 consist of [WS4]2− tetrahedra which are linked to the organic ammonium cations via N–H⋯S hydrogen bonding. The strength and number of the S⋯H
interactions affect the W–S bond lengths as evidenced by distinct short and long W–S bonds. The IR spectra exhibit splitting
of the W–S vibrations, which can be attributed to the distortion of the [WS4]2− tetrahedron. From a comparative study of several known tetrathiotungstates it is observed that a difference of more than
0.033 ? between the longest and shortest W–S bonds in a tetrathiotungstate will result in the splitting of the asymmetric
stretching vibration of the W–S bond. 相似文献
18.
Bikshandarkoil R. Srinivasan Christian N?ther Sunder N. Dhuri Wolfgang Bensch 《Monatshefte für Chemie / Chemical Monthly》2006,121(2):397-411
Four new organic ammonium tetrathiotungstates (N–Me–enH2)[WS4] (1), (N,N′-dm-1,3-pnH2)[WS4] (2), (1,4-bnH2)[WS4] (3), and (mipaH)2[WS4] (4), (N–Me–enH2 = N-methylethylenediammonium, N,N′-dm-1,3-pnH2 = N,N′-dimethyl-1,3-propanediammonium, 1,4-bnH2 = 1,4-butanediammonium, and mipaH = monoisopropylammonium) were synthesized by the base promoted cation exchange reaction and characterized by elemental analysis,
infrared, Raman, UV-Vis and 1H NMR spectroscopy as well as single crystal X-ray crystallography. The structures of 1–4 consist of [WS4]2− tetrahedra which are linked to the organic ammonium cations via N–H⋯S hydrogen bonding. The strength and number of the S⋯H
interactions affect the W–S bond lengths as evidenced by distinct short and long W–S bonds. The IR spectra exhibit splitting
of the W–S vibrations, which can be attributed to the distortion of the [WS4]2− tetrahedron. From a comparative study of several known tetrathiotungstates it is observed that a difference of more than
0.033 ? between the longest and shortest W–S bonds in a tetrathiotungstate will result in the splitting of the asymmetric
stretching vibration of the W–S bond. 相似文献
19.
Melchor González-Dávila J. Magdalena Santana-Casiano Frank J. Millero 《Journal of solution chemistry》2006,35(1):95-111
The oxidation rates of nanomolar levels of Fe(II) in seawater (salinity S = 36.2) by mixtures of O2 and H2O2 has been measured as a function of pH (5.8–8.4) and temperature (3–35∘C). A competition exists for the oxidation of Fe(II)
in the presence of both O2 (μ mol⋅L−1 levels) and H2O2 (nmol⋅L−1 levels). A kinetic model has been applied to explain the experimental results that considers the interactions of Fe(II) with
the major ions in seawater. In the presence of both oxidants, the hydrolyzed Fe(II) species dominate the Fe(II) oxidation
process between pH 6 and 8.5. Over pH range 6.2–7.9, the FeOH+ species are the most active, whereas above pH 7.9, the Fe(OH)02 species are the most active at the levels of CO2−3 concentration present in seawater. The predicted Fe(II) oxidation rate at [Fe(II)]0 = 30nmol⋅L−1 and pH = 8.17 in the oxygen-saturated seawater with [H2O2]0 = 50nmol⋅L−1 (log 10 k = −2.24s−1) is in excellent agreement with the experimental value of log 10 k = −2.29s−1 ([H2O2]0 = 55nmol⋅L−1, pH = 8). 相似文献
20.
The conformation ofэSiOC·H2 radicals was determined by comparison of the ESR data and results of quantum-chemical calculations. Based on the experimental
data, the characteristic times τc of rotational mobility ofэSiOC·H2 radicals grafted onto a silica surface were estimated over the temperature interval from 77 (τc = 15.8 · 10-8 s) to 295 K (τc 1.3 · 10-8 s).
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2092–2095, November, 1999. 相似文献