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1.
Egorochkin A. N. Voronkov M. G. Skobeleva S. E. Zderenova O. V. 《Russian Chemical Bulletin》2001,50(1):43-49
The possibility of application of linear free energy relationships for studying the effects of substituents on the first vertical ionization potentials of amines, I(nN), was substantiated. The I(nN) values depend on the inductive, resonance, and polarizability effects of substituents and are also affected by hyperconjugation. The R
+ resonance parameters of substituents MR3 (M = Si, Ge, Sn) and CH2SiMe3 bound to the N
·+ radical cation center were calculated for the first time. 相似文献
2.
The first vertical ionization potentialsl
1 of molecules RπX (X=Ph, H2C=CH, and HC≡C) depend on the joint influence of the inductive, resonance, and polarizability effects of substituents X, which
are characterized by parameters σ1, σR+, and σα, respectively. The mechanism of conjugation in radical cations formed upon ionization of RπX is changed as compared to neutral RπX molecules, while the substituent X becomes polarized. The conjugation and polarizability effects are strenthened in the
sequence Ph < H2C=CH <HC≡C as Rπ changes from Ph to H2C=CH and HC≡C. The σR+ parameters of Si-, Ge-, and Sn-containing substituents X are dependent on the type of Rπ but are connected by linear dependences in the series of benzene, ethylene, and acetylene derivatives.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1481–1486, August, 1998. 相似文献
3.
The first vertical ionization potentials (IP) of monosubstituted benzenes, hexafluorobenzenes, naphthalenes, anthracenes, furans, thiophenes, and selenophenes and the
secondIP of monosubstituted tellurophenes are related to the inductive, resonance, and polarization parameters of substituents by
dependences of the type {ie2532-2}. The contribution of polarizability effect, {ie2532-3}, to theIP value is determined by the degree of delocalization of the positive charge in radical cations formed upon photoionization
of the compounds studied. The {ie2532-4} resonance parameters of nineteen Si-, Ge-, Sn-, and Pb-containing substitutents in
naphthalene, furan, and thiophene series were calculated.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2434–2438, December, 1998. 相似文献
4.
The first vertical ionization potentials (I) of halides HalX (Hal = Cl, Br, I; X is an inorganic or organic substituent) are linearly related to the inductive (I), resonance (R
+), and polarizability () constants of the substituents X (I = a + bI + cR
+ + d). As the atomic number of the Hal element in the Hal·+X radical cations increases, the inductive interaction is strengthened while the polarizability interaction is weakened. Conjugation remains virtually independent of the Hal atom. The resonance R
+-constants of the MX3 (M = Si, Ge, Sn, Pb) substituents bound to the Hal·+ radical cation centers were first calculated. 相似文献
5.
The effects of X substituents on the energies of charge-transfer bandshv
CT in electronic absorption spectra of charge-transfer complexes of π-, n-, or σ-donors (DX) with π- or σ-acceptors (A) as well
as on the ionization potentialsI
D of individual DX molecules are described by the equationhv
CT(l
D)=a +bσ1 +cσ
R
+
+dσα. When DX and A are fixed, the inductive (bσ1), resonance (cσ
R
+
), and polarization (dσα) contributions tohv
CT andI
D are virtually identical. The electronic structure of the D.+X donor component of the compact [A.−, D.+X] radical-ionic pair in a solution is similar to that of the radical cation generated upon photoionization of the individual
DX molecule in the gaseous phase.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1002–1006, June, 2000. 相似文献
6.
A. N. Egorochkin M. G. Voronkov S. E. Skobeleva T. G. Mushtina O. V. Zderenova 《Russian Chemical Bulletin》2000,49(1):26-32
The first vertical ionization potentialsI(ns) of 69 monosulfides XSY (X, Y=H, Hal, organic, or heteroorganic substituent) are related to the inductive σI resonance (σ
R
+
) and polarizability (σα) constants of the substituents by dependences of theI(nS)=a+bΣσI+bΣσR+bΣσα type. TheI(ns) values are also affected by hyperconjugation which increases on going from XSH to XSY (Y≠H) compounds. The first calculations
of the σ
R
+
parameters characterizing the conjugation of Si-, Ge-, Sn-, and Pb-containing substituents with the S.+ radical cation center are reported. The reasons for weakening of resonance donor properties of heteroorganic substituents
of the +M-type in the systems studied as compared to those of the same substituents in the corresponding aromatic radical cations are
considered.
Translated fromIzvestiya Akademii Nauk. Seriya Khmicheskaya, No. 1, pp. 25–31, January, 2000. 相似文献
7.
A. N. Egorochkin M. G. Voronkov S. E. Skobeleva T. G. Mushtina O. V. Zderenova 《Russian Chemical Bulletin》1990,49(1):26-32
The first vertical ionization potentialsI(ns) of 69 monosulfides XSY (X, Y=H, Hal, organic, or heteroorganic substituent) are related to the inductive σI resonance (σ
R
+
) and polarizability (σα) constants of the substituents by dependences of theI(nS)=a+bΣσI+bΣσR+bΣσα type. TheI(ns) values are also affected by hyperconjugation which increases on going from XSH to XSY (Y≠H) compounds. The first calculations
of the σ
R
+
parameters characterizing the conjugation of Si-, Ge-, Sn-, and Pb-containing substituents with the S.+ radical cation center are reported. The reasons for weakening of resonance donor properties of heteroorganic substituents
of the +M-type in the systems studied as compared to those of the same substituents in the corresponding aromatic radical cations are
considered.
Translated fromIzvestiya Akademii Nauk. Seriya Khmicheskaya, No. 1, pp. 25–31, January, 2000. 相似文献
8.
The ionization processes of phosphorus(III) and (IV) compounds oxidized in the potential range of 1.8–4.0 Vvs. Ag/0.01M AgNO3 in MeCN were studied by chronovoltammetry on a Pt ultramicroelectrode in acetonitrile and by photoelectron spectroscopy in
the gas phase. A relationship between the half-wave potential (E
1/2) and vertical ionization potential (IP
v)E
1/2=0.89IP
v–6.27 is fulfilled in a wide potential range from−0.37 to 3.98 V. The total reorganization energy of the system (1.45–2.50
V) and the energy of reorganization of the solvate shell (0.9–1.9 eV) were estimated.
Translated fromIzvestiya Akademii Nauk. seriya Khimicheskaya, No. 4, pp. 682–689, April, 1999. 相似文献
9.
Unlike theE
HOMO energies, the first vertical ionization potentials (I
1) of monosubstituted ethylenes dependen not only on both the inductive and resonance effects but also on the polarizability
of the substituents, which can be characterized by the σα parameters. The σ
R
+
, σ
p
+
, and σα parameters for 12 silicon-, germanium-, and tin-containing groups were determined using the equations relating theI
1 values and the σI, σ
R
+
, σ
p
+
and σα parameters of the substituents in the molecules of organic compounds. The conjugation of organoelemental substituents with
the double bond is stronger than that with benzene ring; the σ
R
+
parameters in the ethylene and benzene series are related by a linear dependence.
Translated fromIzvestiya Akademii Nauk Seriya Khimicheskaya, No. 9, pp. 1626–1631, September, 1997. 相似文献
10.
DFT(B3LYP) and 2 quantum chemical calculations have been performed for 1-substituted silatranes XSi(OCH2CH2)N (X = H, CH3, CH2Cl, F), their radical cations, and first ionization potentials (IP1) of these silatranes. The calculated values of IP1 agree well with the experiment and make it possible to assign the first band to IP1 in the photoelectron spectra. Analysis of spin density distribution and electronic charges in the radical cations suggests that ionization occurs mainly due to the lone electron pair of nitrogen, participating in intramolecular coordination. The N → Si interaction is broken, and the N...Si distance increases to 335–340 pm. 相似文献
11.
A. N. Egorochkin M. G. Voronkov S. E. Skobeleva T. G. Mushtina O. V. Zderenova 《Russian Chemical Bulletin》2000,49(2):256-260
The dependence was analyzed of the first ionization potentialI(Si−Si) corresponding to detachment of an electron from the σ(Si−Si) highest occupied molecular orbital on the parameters
of organic (X=Me, Et, Bu
t
, Ph, CH=CH2), inorganic (X=F, Cl, Br), and organosilicon (X=SiR3; R is organic radical) substituents in di-, tri-, and tetrasilanes X3SiSiX3. It was found by correlation analysis that out of the three possible effects of substituents X (the inductive, polarizability,
and resonance effects), only the first two of them affect theI(Si−Si) values. This means that no conjugation between the substituent X and the radical cation center occurs in X3Xi±SiX3.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 253–257, February, 2000. 相似文献
12.
The study is concerned with analysis of the energies of formation (E), frequency shifts (Δν) in IR spectra, ionization potentials (IP) of H-complexes, hydrogen bond lengths (r), and spin densities (sd) in H-complexes involving radical cations, obtained from quantum chemical calculations for 20 series
of H-complexes. It was for the first time established that the E, IP, r, and sd values and the changes in enthalpy (δH) depend not only on the inductive and resonance effects but also on the polarizability effect of the substituents bound to
the donor and acceptor centers in the H-complexes. Interrelations between the polarizability effect and the molecular structure
of H-complexes are considered.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 602–608, April, 2006. 相似文献
13.
I. Yu. Shchapin V. I. Fel'dman V. N. Belevskii N. A. Donskaya N. D. Chuvylkin 《Russian Chemical Bulletin》1994,43(1):1-12
Thermal transformations of vinylcyclopropane radical cations (VCP.+) in X-ray-irradiated frozen Freon matrices (CFCl2CF2Cl and CFCl3) were studied by ESR; radical processes involving VCP.+ in solid VCP were simulated.Gauche- andanti-VCP
.+ were found to be the primary radical cations, however, the former, unlike the latter, is stable only under gas-phase conditions. The thermodynamic equilibrium betweenanti-VCP.+ and its less stable distonic form,dist(90,0)-C
5H8
.+, is established in frozen Freon matrices and the VCP host matrix; the structure of dist(90,0)****-C
5H8
.+ is stabilized by a molecule ofanti-VCP. In CFC3, along with dist(90,0)-C5H8
.+,-dimeric resonance [anti-VCP]2
.+ complex was detected. A general scheme of the transformations of VCP.+ in the solid phase has been proposed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 11–21, January, 1994. 相似文献
14.
R. B. King 《Russian Chemical Bulletin》1993,42(11):1772-1781
Reactions of disodium tetracarbonylferrate, Na2Fe(CO)4, with sterically hindered dialkylaminodichlorophosphines, R2NPCl2 (R2N=diisopropylamino, dicyclohexylamino, and 2,2, 6, 6-tetramethylpiperidino) in diethyl ether lead to the air-stable phosphorus-bridging carbonyl derivatives (R2NP)2COFe2(CO)6 as the major products. The phosphorus-bridging carbonyl group in (i-Pr2NP)2COFe2(CO)6 has been found to undergo the following types of reactions: 1)Reduction, 2)Acylation, 3)Extrusion of the carbonyl group. The mechanisms of the reactions have been considered.This work was presented at the Workshop «The Modern Problems of Heteroorganic Chemistry» held on the ship «Nikolai Bauman» during the period May 8–13, 1993.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1858–1867, November, 1993. 相似文献
15.
V. V. Shereshovets N. M. Korotaeva A. S. Vorob'ev V. D. Komissarov I. I. Furlei 《Russian Chemical Bulletin》1994,43(9):1479-1483
The reaction of triphenyl phosphite ozonide with various types of diazo compounds results in their oxidation, which is accomplished by singlet oxygen (1O2) evolved during thermal decomposition of the ozonide. A decrease in the ionization potential of the substrate results in an increase in the overall rate constant of quenching of1O2. In the case of 9-diazofluorene, the main channel of1O2 quenching is physical quenching.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1567–1571, September, 1994.The work was carried out with the financial support of the Russian Foundation for Basic Research (Project No. 93-03-5231). 相似文献
16.
Ramachandran maps of neutral and ionized HCO–Gly–NH2 and HCO–Ala–NH2 peptide models have been built at the B3LYP/6‐31++G(d,p) level of calculation. Direct optimizations using B3LYP and the recently developed MPWB1K functional have also been carried out, as well as single‐point calculations at the CCSD(T) level of theory with the 6‐311++G(2df,2p) basis set. Results indicate that for both peptide models ionization can cause drastic changes in the shape of the PES in such a way that highly disallowed regions in neutral PES become low‐energy regions in the radical cation surface. The structures localized in such regions, and are highly stabilized due to the formation of 2‐centre‐3‐electron interactions between the two carbonyl oxygens. Inclusion of solvent effects by the conductor‐like polarizable continuum model (CPCM) shows that the solute‐solvent interaction energy plays an important role in determining the stability order. © 2008 Wiley Periodicals, Inc. J Comput Chem 2009 相似文献
17.
G. K. Semin E. N. Tsvetkov T. L. Khotsyanova E. V. Bryukhova 《Russian Chemical Bulletin》1999,48(5):906-913
Regularities of transmission of the effect of equatorial and axial substituents were established for a number of chlorine-containing
organic compounds of pentatalent phosphorus using35Cl NQR spectra. The field constants of35Cl NQR frequencies of the chlorine atoms participating in the P−Cl bond were estimated for a series of tetrahedral phosphorus
ions. The35Cl NQR frequencies of chlorine atoms in tetracoordinated ions of pentavalent phosphorus and in analogous isoelectronic silicon
compounds are related by a linear dependence.
Deceased
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 915–922, May, 1999. 相似文献
18.
Curing of diglycidyl ether of bisphenol-A (DGEBA) with phosphorus containing amide amines i.e. bis[3(3’-aminobenzamido phenyl)]methyl
phosphine oxide (MB),bis[3(4’-aminobenzamido phenyl)]methyl phosphine oxide (PB), tris[3(3’-aminobenzamidophenyl)] phosphine
oxide (MT) and tris[3(4’-aminobenzamido phenyl)] phosphine oxide (PT)and conventionally used curing agent 4,4’-diaminodiphenyl
sulfone (D) was studied by DSC. The amines MB, PB, MT and PT were synthesised in the laboratory and were characterized by
determining elemental composition, melting point, and amine equivalent. Structural characterization was done by 1H-NMR and FTIR. The onset temperature of curing depended on the nucleophilicity of the amines and was in the orderMT≈MB<PT<PB<D.
The exothermic peak temperatures were in the orderD>PB>PT>MT≈MB. The char residue of cured epoxy resin was significantly higher
when phosphorus was incorporated in the cured network. Using mixed amine formulations based on amine D and P-containing amines
and the molar ratio of these amines could easily control the curing characteristics. A linear relationship between char yield
and P-content was observed in such formulations.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
19.
20.
The effect of valency of the heteroatom on the spectrochemical evidence of the conjugation in allyl derivatives of SII,VI and PIII,IV was studied by quantum chemical methods. The geometric and electronic structures of thetrans- andgauche-conformers, including those for allyl compounds of PV with equatorial or axial P-C bonds, were calculated. According to the calculations, inversion of the higher occupied molecular orbitals (MO) and the convergence of their energies resulting from the replacement of weak n,-conjugation by strong ,-conjugation should occur on going from SII and PIII to SVI and PV. Increasing the interaction between the higher occupied MO of the fragments in the non-planar conformation of the molecule causes strengthening of the spectral evidence of conjugation: a decrease in the first ionization potential and a bathochromic shift of the long-wavelength absorption band in the electronic spectrum. The increased relative stability of thegauche-conformers of allyl compounds of hypervalent elements was explained by the through-space interaction between the vacant d-orbitals of the SVI and PV atoms and the -orbital of the C=C bond. Charge transfer between the molecular fragments makes the major contribution to the energy of conjugation.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 43–47, January, 1995.The work was carried out with the financial support of the Russian Foundation for Basic Research (Project No. 93-03-5566). 相似文献