Microwave Spectrum and Dipole Moment of 1,3‐dioxolane in the Hindered‐Pseudorotation States v = 0, 1, 2, and 3

The microwave spectrum of 1,3dioxolane (C₃H₆O₂) in the ground and first three excited states of hindered pseudorotation was studied. The transitions corresponding to the _b, _c, and _a components of the dipole moment were identified. The spectrum was analyzed using numerical diagonalization of the effective rotational Hamiltonian for four interacting states of hindered pseudorotation. The rotational constants, centrifugal distortion constants, the constants of interaction between general rotation and hindered pseudorotation, and the distances between the quasidegenerate vibrational levels ₀₁ = 64840.5, ₁₂ = 122231.7 and ₂₃ = 119732.7 MHz are determined. From the Stark effect of microwave transitions, the dipole moment components (in Debye units) in the hinderedpseudorotation states v = 0, 1, 2, and 3 are determined: 0|_b|0 = 1|_b|1 = 1.22, 2|_b|2 = 1.20, 3|_b|3 = 1.21, 0|_c|1 = 0.77, 2|_c3 = 0.66, and 1|_a|2 = 0.19.     

Effect of support on the stabilization energy of Pt, Pd and Ru

Stabilization energies of Pt, Pd and Ru on oxide supports have been determined by the interacting bond method. Supports to ensure better dispersity of metals are suggested.

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Synthesis of new types of strained hydrocarbons by cyclo-codimerization of quadricyclane with norbornenes and their derivatives,catalyzed by palladium complexes

The codimerization of quadricyclane (QC), the valence isomer of norbornadiene (NBD), with norbornene compounds was studied in the presence of Pd(O) complexes. Codimerization of QC with norbornene, 5-methyl- and 5-methylenenorbornene, exo-tricyclo[3.2.1.0^2,4]octene-6, tetracyclo[4.2.0.0^2,4.0^3,7]nonene-8, and penta- and hexacyclic NBD dimers was carried out in the presence of PPh₃-activated Pd₂(DBA)₃·CHCl₃ to afford a new class of hexa- to nonacyclic strained hydrocarbons with exo- and endo-tetracyclo[4.2.0.0^2,4.0^3,7]nonane fragments.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2572–2577, November, 1991.     

Approximation by Fourier sums of classes of functions with several bounded derivatives

An ordered estimate is obtained for the approximation by Fourier sums, in the metric ofd=(d ₁ , ...,d _n ), 1<dj<,j=1, ...,_n of classes of periodic functions of several variables with zero means with respect to all their arguments, having m mixed derivatives of order a¹..., a^m., aⁱ rⁿ. which are bounded in the metrics ofp ⁱ =p ₁ ⁱ , ..., p _n ⁱ , i

j ⁱ <,i=i, ...,n, j=1, ...,n by the constants ₁, ., _m, respectively.Translated from Matematicheskie Zametki, Vol. 23, No. 2, pp. 197–212, February, 1978.     

Cooligomerization of allyl acetate with norbornadiene and its derivatives catalyzed by nickel complexes

Conclusions The cyclocooligomerization of allyl acetate with norbornadiene and its derivatives to compounds which are not readily accessible in the series tricyclo[4.2.1.0_2,5]nonane, tetracyclo[4.3.0.0_2,3.0^2,4]nonane and tetracyclo[4.4.1.0^2,5.0^7,10,]undecane has been achieved with yields of 60–95%, involving the participation of low-valency nickel complexes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 154–160, January, 1987.     

Microwave spectrum, centrifugal distortion, dipole moment and conformation of 2-methyl-1,3-dioxane

Microwave spectrum of 2-methyl-1,3-dioxane has been investigated in the frequency range 8–40 GHz. Rotational a-type and c-type transitions with J≤40 have been identified. Rotational constants A = 4658.122(2) MHz, B = 2503.221(1) MHz, C = 1783.950(1) MHz and centrifugal distortion constants for the ground vibrational state have been found. Dipole moment components μ_a = 1.43 ± 0.01 D, μ_c = 1.15±0.01 D and overall dipole moment μ = 1.84±0.02 D have been determined. The data obtained are in accord with the chair conformation of the molecule having equatorial arrangement of the methyl group. Original Russian Text Copyright ? 2006 by A. Kh. Mamleev, R. V. Galeev, L. N. Gunderova, M. G. Faizullin, and A. A. Shapkin __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 47, No.2, pp. 373–375, March–April, 2006.     

Structure and spectra of 1,3-dioxanes. microwave spectrum,structural parameters and <Emphasis Type="Italic">ab initio</Emphasis> calculations of 1,3-dioxane

Microwave spectra of the 1,3-dioxane molecule (C₄H₈O₂) with the main isotopic composition and four its isotopomers (¹³C(2)¹²C₃H₈ ¹⁶O₂, ¹³C(4)¹²C₃H₈ ¹⁶O₂, ¹³C(5)¹²C₃H₈ ¹⁶O₂, ¹⁸O(1)¹²C₄H₈ ¹⁶O) are investigated in a frequency range of 28–44 GHz. Rotational transitions of b-and c-types with 2 ≤ J ≤ 5 are identified. Rotational constants, quartic constants of centrifugal distortion, isotope-substituted r _s-and effective r ₀-structures of the molecule ring are determined. Experimental data are compared to the results of quantum chemical calculations of different levels.     

Plasma diffusion in a toroidal stellarator

Particle trajectories in a gently toroidal stellarator are investigated. The distribution function for the particles is determined in the absence of collisions.     

Electron paramagnetic resonance of quasi-one-dimensional crystal [Nd2(Cl3COO)6(H2O)3]n · nH2O

A quasi-one-dimensional single crystal of [Nd₂(Cl₃COO)₆(H₂O)₃]_n · nH₂O in which chains are built up of two alternating neodymium-ion dimer fragments is studied by the EPR technique. It is found that anisotropic interactions between neodymium ions in a chain are responsible for the complex shape of the EPR spectrum. Two groups of EPR signals are distinguished in the spectrum. Each group corresponds to one of the chain dimers disturbed by the interaction with neighbors in the chain. The shape of the EPR spectra is interpreted as a superposition of the spectra of chain fragments which have different lengths and are formed by the alternating magnetic triplet and nonmagnetic singlet states in the chain. Consideration is given to two cases when two alternating dimer fragments are either equivalent or nonequivalent to each other. It is shown that the spectral shape is primarily determined by the superposition of the spectra of an isolated triplet state (S=1), two interacting triplet states, and three interacting triplet states whose weighting contributions differ for the above two cases. The tensors of the anisotropic spin-spin interaction are determined, and the contribution from the isotropic component of the interaction is estimated.