Microwave spectroscopic study on the molecular structure and the quadrupole coupling constants of thionyl chloride

Microwave spectra of thionyl chloride, SO³⁵Cl₂ and SO³⁵Cl³⁷Cl, in the frequency range 8–25 GHz have been analyzed. The rotational constants have been obtained from the low J transition frequencies. The r_S coordinates of Cl atoms and the r_o structure have been evaluated with some assumptions: r(S-O) = 1.435 ± 0.011± Å, r(S—Cl) = 2.072 0.005 Å, ∠ OSCl = 108.00 ± 0.06°, ∠ ClSCl = 97.15 ± 0.30°. Nuclear quadrupole coupling constants have been obtained for the SO³⁵Cl₂, species: x_aa = ?25.02 ± 0.04 MHz, x(_bb = ?0.25 ± 0.04 MHz, X_cc = 25.27 ± 0.08 MHz, and X_zz = ?96.75 MHz. The values obtained are compared with those of other workers.     

Non-empirical interpretation of nitrogen 14 nuclear quadrupole coupling constants

The ¹⁴N nuclear quadrupolar coupling constants have been calculated for a series of nitrogen containing molecules from ab initio SCF-LCAO-MO wavefunctions built on basis sets of Gaussian type atomic functions. The various nuclear and electronic (from MO's, atoms, basis functions) contributions to the total field gradient have been analyzed and their relation to molecular and electronic structure is discussed.The effect of the nature of the basis set on the accuracy of the computed field gradients has also been studied.

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Zusammenfassung Die ¹⁴N-Kernquadrupol-Kopplungskonstanten sind für eine Reihe von N-haltigen Verbindungen aus ab initio-Wellenfunktionen, die auf Gauß-Orbitalen basieren, berechnet worden. Die einzelnen Kern- und Elektronenbeiträge zum Feldgradienten wurden untersucht und diskutiert, desgleichen der Einfluß des Typus der Basis auf die Genauigkeit der Resultate.

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Résumé Les constantes de couplage quadrupolaire nucléaire de ¹⁴N ont été calculées pour une série de composés azotés à partir de fonctions d'onde ab initio SCF-LCAO-MO (Hartree-Fock) construites sur une base de fonctions atomiques gaussiennes. Les diverses contributions nucléaires et électroniques (provenant des orbitales moléculaires, des atomes, des fonctions atomique de base) au gradient de champ total ont été analysées et reliées aux caractéristiques structurales des molécules considérées.L'effet de la nature de la base de fonctions atomiques sur la précision des gradients de champs calculés a aussi été étudié.

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We thank Drs. H. Basch, J. L. Calais, J. F. Harrison and P. Pyykkö for sending us test calculations for checking our program and Drs. H. Basch and G. Berthier for communicating to us the molecular wavefunctions of some of the nitrogen containing heterocycles.     

Temperature dependent deuterium quadrupole coupling constants of short hydrogen bonds

Very short hydrogen bonds universally show large positive dependences of the deuterium NMR quadrupolar coupling constant with temperature. We present temperature dependent NMR data for eight such systems, with OO distances of between 238 and 250 pm, and show we can model the temperature dependences by density functional methods, as long as proper attention is paid to intermolecular effects and intermode couplings.     

An oxidation with thionyl chloride

The reaction of the 2-methylquinoline-3-carboxylic acid 1b with thionyl chloride gave the dichlorothiolactone 2 , the structure of which was confirmed by chemical transformations.     

Sensitivity of monomer nuclear quadrupole coupling constants to hydrogen bond formation

Ab initio calculations on several representative complexes have been carried out to show the sensitivity of quadrupole coupling constants to hydrogen bond formation, and particularly the sensitivity to orientation in the complex. Spectroscopic structural determinations based on nuclear quadrupole coupling constants are examined for five representative systems. It appears that nuclear quadrupole coupling constants may give orientational angles accurately, but inaccuracy may amount to ≈ 15° in certain instances.     

Microwave spectrum,centrifugal distortion constants,dipole moment and quadrupole coupling constants of pentafluoropyridine

Pentafluoropyridine has been analysed in the frequency range of 8 to 18 GHz at dry ice temperature, using a conventional 100 kHz Stark modulated microwave spectrometer. The rotational constants and centrifugal distortion constants are A = 1481.539 ± 0.003 MHz, B = 1075.348 ± 0.004 MHz and C = 623.101 ± 0.001 MHz; and d_J = ?0.39 ± 0.06 kHz, d_JK = 1.86 ± 0.27 kHz, d_K = 0.70 ± 0.1 kHz, d_EJ = (0.3 ± 0.03) × 10^?6 and d_EK = (?1.5 ± 0.2) × 10^?6. The electric dipole moment has been found to be 0.98 ± 0.08 D and the values of the quadrupole coupling constants are x_aa = 1.94 ± 0.22 MHz, x_bb = ?4.08 ± 0.06 MHz and x_cc = 2.14 ± 0.22 MHz. A simple analysis based on Townes and Dailey theory points to a considerable increase in the π-electron density and excess charge on the nitrogen site.     

Reactions of salicylamides with thionyl chloride

A series of compounds having the 1,2,3-benzoxathiazin-4 (3H) one 2-oxide structure have been synthesized by the interaction of thionyl chloride with the appropriate salicylamide. Some properties of these compounds as well as some by-products are described.     

Polymerization of N-vinylcarbazole by thionyl chloride

The polymerization of N-vinylcarbazole (NVC) initiated by SOCl₂ in benzene and nitrobenzene solvents was studied at 32°C. R_p is first order with respect to SOCl₂ concentration and also to NVC concentration up to a certain NVC concentration, after which it falls. Rate and the molecular weight increase with increasing dielectric constant of the medium. The rate and molecular weight are depressed by the addition of amines, thiophene, and water. The degree of polymerization is independent of SOCl₂ and NVC concentration. A conventional cationic mechanism has been suggested, and a suitable kinetic scheme has been proposed in conformity with the findings.     

Coupled cluster and DFT calculations of 14N nuclear quadrupole coupling constants

The dependence of ¹⁴N quadrupole coupling constants calculated using coupled cluster theory on the level of approximation is examined for a series of small molecules. For HCN, HNC, CH₃CN, and CH₃NC, we use the coupled cluster singles‐and‐doubles with a noniterative perturbative triples correction—CCSD(T)—approach, and we analyze the basis set dependence of the results. For aziridine, diazirine, and cyclopropyl cyanide, we use the CCSD(T) approach, but smaller basis sets, and for the largest studied molecules—quinuclidine and hexamine—we present CCSD results. The differences between computed and experimental values for the best basis sets used are ≈ 5% at the CCSD level and decrease noticeably at the CCSD(T) level. The ‐ N≡C bonds are an exception—in this case the quadrupole coupling constants are very small, hence the differences between theory and experiment become larger (up to 9%). We also consider the performance of density functional theory, comparing the results for different density functionals with the coupled cluster values of the same constants. Most of the functionals provide results systematically improved with respect to the Hartree–Fock values, with ¹⁴N coupling constants in ‐ N≡C bonds being again an exception. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Bond orbital analysis of the deuteron quadrupole coupling constants in MD4 molecules

The deuteron quadrupole coupling constants were used as constraints on the bond orbital functions of a series of MD₄ molecules (M=B, C, N, Al, Si, P). It was demonstrated that a minimal basis set may be sufficient to describe first row deuterates, but not for second row deuterates, where double zeta orbitals are needed.This work was started when the author was a post doctoral fellow at Battelle Memorial Institute, Columbus, Ohio.     

Reaction of 2-thiobenzazoles with thionyl chloride

A new reaction in the benzimidazole series, viz., replacement of the mercapto group by chlorine by the action of thionyl chloride on 2-thiobenzimidazoles, was discovered. Benzoxazolone is formed by treatment of 2-thiobenzoxazole with thionyl chloride, and 2,2-dithiobis(2-benzothiazole) is formed from 2-thiobenzothiazole.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1047–1050, August, 1985.     

An ab initio calculation of 14n quadrupole coupling constants

Ab initio SCF-MO calculations of ¹⁴N quadrupole coupling constants are reported for HCN, HNC, CH₃CN, CH₃NC, NH₃, NH₂NH₂, FCN, N₂O, (CN)₂, BrCN, pyridine and pyrazine. There is excellent correlation between calculation and experiment yielding Q = 1.503 ± 0.159 × 10^?26 cm² for the ¹⁴N nuclear quadrupole moment. Dunning sp basis sets are more than adequate for such calculations, STO/4G basis sets yielding almost identical results for pyridine and pyrazine. Unsuccessful attempts were made to correlate coupling constants with electronic population analysis indices.     

Nuclear spin-spin coupling constants in a coupled-cluster polarization propagator approach

A recently derived coupled-cluster doubles polarization propagator approximation (CCDPPA) for excitation energies and transition moments is extended to the calculation of nuclear spin-spin coupling constants. As expected, in cases where the perturbation is small (e.g. C₂H₂) the difference between results obtained using the present scheme and results obtained using the perturbative second-order polarization propagator approach (SOPPA) is small (1-5%). However, for CH⁺ the difference is found to be more than 40%.     

Nitrogen-14 quadrupole coupling constants in N2O3 by isotopic labelling

Several microwave transitions of O¹⁵N…NO₂ and ON…¹⁵NO₂ have been measured under high resolution using a pulsed-nozzle Fourier transform spectrometer. The ¹⁴N quadrupole coupling constants in the inertial axis system have been determined for both nitrogen atoms. The quadrupole coupling constants for ON …¹⁵NO₂ are eQq_aa = −0.5203(20) and eQq_bb = −4.1981(19) MHz, and for O¹⁵N…NO₂ are eQq_aa= −1.7999(13) and eQq_bb = 0.0808(17) MHz. The ¹⁴N quadrpole coupling constants determined by Kukolich for the main species ON…NO₂ should be reversed with respect to the NO and NO₂ groups. Combining the present data with the main species constants allows the complete quadrupole coupling tensor to be estimated for the NO₂ group; the tensor in N₂O₃ lies within 2° of the N…N bond direction and within 0.4° of the bisector of the ONO angle. Spin-rotation effects are significant for nitrogen in the NO group; C_aa is determined to be 8 ± 2 kHz for ¹⁴N in ON…¹⁵NO₂ and −15 ± 3 kHz for ¹⁵N obtained directly from splittings in the spectrum of O¹⁵N… ¹⁵NO₂.     

Direct polyamidation with thionyl chloride in N-methyl-pyrrolidone

Mechanistic features of the reaction promoted by thionyl chloride and amides such as N-methylpyrrolidone (NMP) were studied. The reaction was effective in the amidation of carboxylic acids, but not effective in the esterification. The amidation was affected by the kind and the amount of amides used, most favorably by two equivalents of NMP with respect to the acid. These amides were assumed to be involved in the intermediate formation, and the reaction was proposed to proceed via Vilsmeier adducts derived from thionyl chloride and the amides, and through activation of a carboxylic acid different from an acyl chloride. The reaction was successfully applied to the direct polycondensation of aromatic dicarboxylic acids and diamines in NMP at 70°C to produce polyamides with high molecular weights. Initial reaction of dicarboxylic acids with the adducts, additive effect of tertiary amines, and polycondensation temperatures were studied in terms of the inherent viscosity of the polymers produced.     

Lithium-lithium tetrachloroaluminate reference electrode in thionyl chloride

Three in situ techniques for charging current compensation (c.c.c.) in d.c. polarography are described. These methods envisage the superposition of an a.c. ripple and analogue processing of the response to yield a quantity proportional to the d.c. charging current. The theory of these procedures outlined in this paper, enables one to approach c.c.c. without any reliance on trial and error. Details of the appropriate circuitry and supporting experimental verification of the theory are also presented.     

亚硫酰氯还原的电催化研究

利用碳粉微电极和显微Raman分子探针技术研究了SOCl~2阴极还原的电催化性能.在八硫杂氢化酞菁的催化作用下, SOCl~2还原过程中的产物硫将进一步还原.碳粉微电极表面沉积物形貌和Raman光谱分析表明硫是引起电极钝化的另一个重要因素,催化剂存在的条件下,硫进一步还原的结果是使碳表面有不同程度的活化,这对提高电池容量和电压有较大影响.