The geometric structure and conformation of (trifluoromethyl)thiobenzene, C
6H
5SCF
3, has been determined by two independent gas electron diffraction (GED) studies at the Universities of Moscow and ...Ivanovo and by quantum chemical calculations. Both experimental studies result in perpendicular orientation of the S
CF
3 bond relative to the benzene plane. This result is confirmed by several quantum chemical calculations (HF/6-31G(d), B3LYP/cc-pVTZ, MP2/6-31G(d), MP2/6-311+G(d,p) and MP2/cc-pVTZ) which predict single-minimum potential functions for internal rotation around the C(sp
2)
S bond. A double-minimum potential function predicted by the B3LYP/6-31G(d) calculation is not compatible with the experiment. B3LYP and MP2 calculations with large basis sets (6-311+G(d,p) and cc-pVTZ) predict barriers to internal rotation around the C(sp
2)
S bond between 2.4 and 2.6
kcal/mol. The geometric parameters of both experimental studies agree with each other within the experimental uncertainties, except for the C
F bond distance. The effect of fluorination of the methyl group in thioanisole, C
6H
5SCH
3, i.e., conformational change from planar orientation of the S
CH
3 bond to perpendicular orientation of the S
CF
3 bond, is rationalized on the basis of a natural bond orbital (NBO) analysis. The predominant effect is loss of conjugation between the p-shaped sulfur lone pair and the π system of the ring upon fluorination.
Evolution of intergovernmental fiscal relations in Russia in the 1990s is analysed, including the results of the realisation of the Concept of intergovernmental fiscal relations reform in the Russian ...Federation in 1999-2001. On the basis of centralisation of budget resources and decentralisation of budget responsibilities there have been elaborated alternative approaches to the evaluation of results and perspectives of the formation of a Russian model of fiscal federalism. It is argued for policy reorientation in the field of intergovernmental fiscal relations to distinguish between tax and budget powers, to distribute responsibilities among authorities of different levels in view of stable proportions achieved by 2002 related to budget resources' allocation. Main points of the realisation of the government Programme in the field of the fiscal federalism development in the Russian Federation for the period till 2005 are disclosed.
The Andreev reflection spectra were studied for the first time in the magnetic superconductor Dy0.6Y0.4Rh3.85Ru0.15B4. It is found that an external magnetic field (up to 0.7 Hc2) is a strong ...stimulator of superconductivity in contrast with traditional superconductors with a singlet pairing. The ratio 2\Delta/kBTc \approx 4.0 obtained for some contacts is higher than the value 3.52 which is typical of conventional superconductors with a weak electron-phonon interaction. It has been proposed that in Dy0.6Y0.4Rh3.85Ru0.15B4 a triplet mechanism of superconducting pairing is realized.
The molecular structure of methyl(vinyl)-
N-nitroamine has been reinvestigated by gas-phase electron diffraction and ab initio MO calculations. The methyl(vinyl)-
N-nitroamine has been found from ab ...initio MO calculations to exist as a mixture of two conformers: an anti- and a syn-form, the former being more stable. The energy difference is predicted to be 3.3 kcal mol
−1. The results obtained by the calculation were used to evaluate vibrational amplitudes required for further electron diffraction analysis.
In the electron diffraction analysis some bond length and bond angle differences found by ab initio calculations were assumed. The vapour was assumed to consist only of the anti-form. The torsional angle around the NC
vinyl and NN bonds were refined. It has been found that the amine group is planar. The vinyl group is out of the molecular plane by 19° (
r
a-structure).
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