<sup>35</sup>Cl NQR Spectra of Organyl(chloroalkyl) Sulfides

Воронков, М. Г.; Dolgushin, G. V.; Фешин, В. П.; Turchaninova, L. P.; Корчевин, Н. А.; Deryaghina, Eleonora N.

doi:10.1515/zna-1992-1-226

Cited by 12 publications

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“…However, usually the substituent properties are described by the Hammett and Taft constants determined at room temperature, and the differences in the correlations between these constants and the quadrupole coupling constants are explained by coupling or steric effects. 29,30 As shown by the results of our studies, the assumption that the substituents' properties are the same at room temperature and at liquid nitrogen temperature is an oversimplification for thiazides, leading to incorrect conclusions. In order to be able to compare the data on electron-acceptor or electron-donor properties obtained by different experimental methods, all the experiments must be performed at the same temperature, as this ensures that inter-and intramolecular interactions are the same and do not modify the properties of the substituent by, e.g., changes in its conformation.…”

Section: Inductive Effectsmentioning

confidence: 88%

Electronic structure of thiazides studied by ³⁵Cl‐NQR spectroscopy and DFT calculations

Latosińska

2003

Magnetic Reson in Chemistry

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NQR frequencies were determined for the 35 Cl isotope in a few benzodithiazine derivatives, chlorothiazide (CTZ), hydrochlorothiazide (HCTZ), althiazide (ATZ), trichloromethiazide (TCTZ), benzthiazide (BTZ) and furosemide (FSE), at liquid nitrogen and room temperatures. It was found that changes of the substituent at C-3 are transferred through a system of coupled rings on to the chlorine atom at C-6. The substituents occurring in thiazides can be ordered according to increasing electron-acceptor properties as -CH 2 SCH 2 Ph < -CH 2 SCH 2 CH CH 2 < -CHCl 2 . At the liquid nitrogen temperature -CH 2 SCH 2 Ph and -CH 2 SCH 2 CH CH 2 are electron donors, and CHCl 2 is an electron acceptor, whereas at room temperature -CH 2 SCH 2 Ph is an electron donor and -CH 2 SCH 2 CH CH 2 and -CHCl 2 are electron acceptors. The character of the substituent properties is preserved irrespective of whether the system is aromatic or aliphatic. The NQR frequencies and substituents properties are well reproduced by the DFT B3LYP/6-311+G(2d,p) method. The topological properties of the Laplacian of the electron density were analysed within the AIM (atoms in molecules) approach. The changes in the electron density at C-3 are correlated with the biological activity of the compounds studied.

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Section: Inductive Effectsmentioning

confidence: 88%

Electronic structure of thiazides studied by ³⁵Cl‐NQR spectroscopy and DFT calculations

Latosińska

2003

Magnetic Reson in Chemistry

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“…The N Q R frequencies of halogen atom s in molecules of the series Y (CH 2)"X (where Y is a halo gen atom or a group containing it) usually oscillate when the n increases successively (see, e.g., [1][2][3][4][5]). The most convincing explanation of this oscillation is the polarization of a chemical bond by the charge of a geminal atom and the transmission of this effect along a chain of atoms [2].…”

Section: Introductionmentioning

confidence: 99%

^79,81Br NQR Spectra of Alkyl(4-Bromophenyl)Sulphides

Фешин

Nikitin

Aliev

1994

Zeitschrift Für Naturforschung A

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The 79,81Br NQR spectra of compounds of the series 4-BrC6H 4SR with R = (C H 2)"H (n = 1,2, 4 -9 ), (CH 2)I)C H (C H 3)2 (n = 0 -2 ) and C H m(C H 3)3_m were obtained at 77 K. The halogen atom electron densities in these compounds and chlorine-containing analogs are compared. The ratio of the amplitudes of the N Q R frequency oscillations in chlorine-and brom ine-containing compounds with R = (CH2)nH corresponds to the ratio of the polarizabilities of 35C1 and 79Br. The variation of the alkyl groups R influences the electron distribution of the halogen atom.

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“…* The Si--O bond length is 9 According to the rule formulated in Ref. 65, in the geminal Y--C--X systems, the electron density is shifted from the more electronegative Y atom to the less electronegative X atom; conversely, in the vicinat Y--C--C--X systems it is shifted from the X atom to Y. This regularity was convincingly confirmed by the data of 35CI NQR, 65 vibrational and electron spectroscopy, and quz~ntum-chemical c~lculations.…”

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confidence: 99%

Reactions of α-elimination of silanones as a path for formation and destruction of siloxane structures

Воронков

1998

Russ Chem Bull

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Based on modern stereoelectronic concepts, our results, and published data, we explained the paths of formation and destruction of linear and cyclic oligo-and polysitoxanes via intramolecular geminal decomposition or Si(OR)X groups, which results in the intermediate formation of short-lived silanones R2Si=O. The latter are subsequently oligomerized, polymerized, or inserted into the Si--X bonds (X = O, CI, etc.) of the trapping agents.

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³⁵Cl NQR Spectra of Organyl(chloroalkyl) Sulfides

Cited by 12 publications

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Electronic structure of thiazides studied by ³⁵Cl‐NQR spectroscopy and DFT calculations

Electronic structure of thiazides studied by ³⁵Cl‐NQR spectroscopy and DFT calculations

^79,81Br NQR Spectra of Alkyl(4-Bromophenyl)Sulphides

Reactions of α-elimination of silanones as a path for formation and destruction of siloxane structures

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35Cl NQR Spectra of Organyl(chloroalkyl) Sulfides

Cited by 12 publications

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Electronic structure of thiazides studied by 35Cl‐NQR spectroscopy and DFT calculations

Electronic structure of thiazides studied by 35Cl‐NQR spectroscopy and DFT calculations

79,81Br NQR Spectra of Alkyl(4-Bromophenyl)Sulphides

Reactions of α-elimination of silanones as a path for formation and destruction of siloxane structures

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³⁵Cl NQR Spectra of Organyl(chloroalkyl) Sulfides

Electronic structure of thiazides studied by ³⁵Cl‐NQR spectroscopy and DFT calculations

Electronic structure of thiazides studied by ³⁵Cl‐NQR spectroscopy and DFT calculations

^79,81Br NQR Spectra of Alkyl(4-Bromophenyl)Sulphides