Etudes expérimentales et théoriques des déplacements chimiques du carbone-13 en serie isothiazolique

1975 ◽  
Vol 53 (11) ◽  
pp. 1677-1681 ◽  
Author(s):  
Robert Faure ◽  
Jean-Richard Llinas ◽  
Emile-Jean Vincent ◽  
Michel Rajzmann
Keyword(s):  
Long Range ◽  
Sulfur Atom ◽  
Chemical Shifts ◽  
D Orbitals ◽  
Theoretical Results ◽  
Dominant Influence

During a general n.m.r. study of five-membered heterocycles with two hetero-atoms, we measured the 13C chemical shifts, the vicinal couplings [Formula: see text] and the long range couplings for a series of variously substituted isothiazoles. At that time we were able to compare the effects of the various substituents to the effect of the group of hetero-atoms and to demonstrate the pre dominant influence of dissymmetry of the latter on the values of the observed parameters. Moreover, a comparison with theoretical results based on a CNDO model showed deficiencies which justify the search for a representation better adapted, by the introduction of d orbitals, to the sulfur atom. Studies of CNDO parametrization for third row elements are being undertaken by other means. [Journal translation]

On the long-range relativistic effects in the 15 N NMR chemical shifts of halogenated azines

2017 ◽  
Vol 55 (11) ◽  
pp. 990-995 ◽  
Author(s):  
Dmitry O. Samultsev ◽  
Yury Yu. Rusakov ◽  
Leonid B. Krivdin
Keyword(s):  
Long Range ◽  
Chemical Shifts ◽  
Relativistic Effects ◽  
Nmr Chemical Shifts

Long-range couplings in the N.M.R. spectra of isoquinolines

1971 ◽  
Vol 24 (11) ◽  
pp. 2311 ◽  
Author(s):  
F Balkau ◽  
ML Heffernan
Keyword(s):  
Long Range ◽  
Chemical Shifts ◽  
Coupling Constants

The N.M.R. spectra of several isoquinolines have been recorded and analysed. Extensive spin-decoupling allowed the magnitudes and relative signs of the long- range coupling constants to be determined, and these are presented. Several unusual features of the chemical shifts and coupling constants are noted.

Proton magnetic resonance spectra of some benzo[b]thiophens. An investigation of substituent effects in a heteroaromatic system

1968 ◽  
Vol 21 (7) ◽  
pp. 1853 ◽  
Author(s):  
B Caddy ◽  
M Martin-Smith ◽  
RK Norris ◽  
ST Reid ◽  
S Sternhell
Keyword(s):  
Magnetic Resonance ◽  
Long Range ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Spin Coupling ◽  
Heteroaromatic System ◽  
Spin Spin Coupling ◽  
Magnetic Resonance Spectra

N.m.r. data for 19 5-substituted and 13 polysubstituted benzo[b]thiophens are tabulated. The influence of the substituents at C5 on the chemical shifts of H4 and H6 is discussed. Long-range interproton spin-spin coupling between H3 and H7, and between H2 and H6, is general in benzo[b]thiophens. The vicinal coupling J6,7 in 5-substituted benzo[b]thiophens varies directly and linearly with the electronegativity of the substituents at C5.

Studies on the PMR Spectra of Oxetanes. VI 2-(3-Chlorophenyl)oxetane and 2-(2-Chlorophenyl)oxetane at 60 and 100 MHz

1974 ◽  
Vol 29 (12) ◽  
pp. 1902-1906 ◽  
Author(s):  
Jukka Jokisaari
Keyword(s):  
Long Range ◽  
Chemical Shifts ◽  
Methine Proton ◽  
Coupling Constants ◽  
Coupling Constant ◽  
Proton Proton ◽  
Temperature Range ◽  
Proton Coupling ◽  
Phenyl Proton ◽  
Pmr Spectra

The 100 MHz spectra of the phenyl protons in 2-(3-chlorophenyl) oxetane and 2-(2-chlorophenyl) oxetane have been analysed. The 60 MHz PMR chemical shifts and proton-proton coupling constants have been studied in the temperature range from -20 C to +80 °C. The chemical shifts were sensitive to temperature, while the coupling constants were not, except the long range 5Jm coupling constant between the methine proton and the meta positioned phenyl proton in 2-(2-chlorophenyl) oxetane.

Long-range proton-fluorine spin-spin coupling. Further evidence for a 'direct' mechanism

1973 ◽  
Vol 26 (12) ◽  
pp. 2659 ◽  
Author(s):  
W Adcock ◽  
SQA Rizvi
Keyword(s):  
Long Range ◽  
Chemical Shifts ◽  
Variable Temperature ◽  
Strong Support ◽  
Spin Coupling ◽  
Coupling Mechanism ◽  
Direct Mechanism ◽  
Spin Spin Coupling

A variable temperature p.m.r. study of outho- and peri-acetyl substituted fluoro-naphthalenes (including o-fluoroacetophenone) has been carried out. Further, 1-fluoro- 8-methylnaphthalene (previously unknown) has been synthesized and its p.m.r. spectra has been measured at various temperatures. The data, together with 19F substituent chemical shifts (SCS) for ortho-substituted cyanofluoronaphthalenes, provide further strong support for a through-space coupling mechanism (JMe,F).

The analysis of the proton magnetic resonance spectra of heteroaromatic systems. V. Diazanaphthalenes

1965 ◽  
Vol 18 (5) ◽  
pp. 707 ◽  
Author(s):  
PJ Black ◽  
ML Heffernan
Keyword(s):  
Carbon Tetrachloride ◽  
Magnetic Resonance ◽  
Long Range ◽  
Iterative Procedure ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Direct Calculation ◽  
Coupling Constants ◽  
Dilute Solutions ◽  
Magnetic Resonance Spectra

The proton magnetic resonance spectra of the four isomeric diazanaphthalenes, quinoxaline, phthalazine, quinazoline, and cinnoline, all as dilute solutions in carbon tetrachloride and acetone, have been investigated at 100 Mc/s. The chemical shifts and coupling constants have been obtained by direct calculation or, where appropriate, by an iterative procedure. Long-range coupling constants between protons separated by five and six bonds have been observed.

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