Etude par résonance magnétique nucléaire de composés organiques contenant des chalcogènes. I. L'anisole et ses analogues soufré, sélénié et tellure

1978 ◽  
Vol 56 (15) ◽  
pp. 2008-2012 ◽  
Author(s):  
Gabriel Llabres ◽  
Marcel Baiwir ◽  
Léon Christiaens ◽  
José Denoel ◽  
Léopold Laitem ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Heavy Atom ◽  
Methyl Groups ◽  
Electronic Effects ◽  
Methyl Halides ◽  
Planar Configuration ◽  
Résonance Magnétique ◽  
Atom Effect

Results are reported of a study by 1H and 13C nuclear magnetic resonance of anisole, thioanisole, selenoanisole and telluroanisole as well as of several of their para-substituted derivatives. If these compounds are considered as substituted methyl groups, they display a behaviour analogous to that of the methyl halides. It is possible to demonstrate that a linear relation exists between the proton and the carbon chemical shifts in the anisole series as well as in the methyl halides. Although these results most frequently are interpreted in terms of electronic effects, a 'heavy atom effect' must be invoked for the tellurium compounds. The experimental results do not contradict the hypothesis that the compounds studied have a planar configuration [Journal translation]

Molybdenum-95 nuclear magnetic resonance studies on disubstituted molybdenum(0) carbonyls

1988 ◽  
Vol 66 (3) ◽  
pp. 397-400 ◽  
Author(s):  
Elmer C. Alyea ◽  
Arpad Somogyvari
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Phosphine Ligands ◽  
Electronic Effects ◽  
Magnetic Resonance Studies ◽  
Nitrogen Ligands ◽  
Cis And Trans ◽  
Cyclic Nitrogen

Molybdenum-95 nmr spectral data are reported for 40 cis- and trans-Mo(CO)4LL′ compounds and the chemical shifts discussed in relation to a simplified Ramsey expression for the paramagnetic shielding term. The identification of mixtures of products of the type Mo(CO)6−nLn is shown to be easily accomplished by 95Mo nmr spectroscopy. The 95Mo chemical shifts provide a sensitive probe of structural and electronic effects, as illustrated for several cyclic nitrogen ligands as well as a range of phosphine ligands in the Mo(CO)4LL′ complexes.

NUCLEAR MAGNETIC RESONANCE SPECTRA OF DURENE AND MESITYLENE DERIVATIVES

1963 ◽  
Vol 41 (3) ◽  
pp. 711-713 ◽  
Author(s):  
E. Bullock
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Aromatic Ring ◽  
Chemical Shifts ◽  
Methyl Groups ◽  
Mesomeric Effect ◽  
Nuclear Magnetic Resonance Spectra ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The nuclear methyl groups and ring protons in nitro- and dimethylamino-durenes and -mesitylenes show considerable chemical shifts relative to the parent hydrocarbons. The shifts are generally in the direction expected from a mesomeric effect, despite the lack of coplanarity between the aromatic ring and the substituent.

Étude en résonance magnétique nucléaire du 13C des F-méthyl-4 coumarines

1987 ◽  
Vol 65 (6) ◽  
pp. 1356-1360 ◽  
Author(s):  
Raphaël E. Pastor ◽  
Joëlle Fabron ◽  
Aimé Cambon ◽  
You-Chuan Hu
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Alkyl Substituent ◽  
Coupling Constant ◽  
Methyl Substituent ◽  
Slight Effect ◽  
Nuclear Magnetic Resonance Spectra ◽  
Résonance Magnétique ◽  
Magnetic Resonance Spectra

Analysis of 13C nuclear magnetic resonance spectra of six 4-F-methyl coumarins are reported. This 4-F-alkyl substituent has a very slight effect on the chemical shifts of different carbon atoms. Only the C-10, C-4, and C-5 atoms are really affected and are shifted towards higher fields. The size of these effects was evaluated and compared with the corresponding effects of a 4-methyl substituent. The most important fact is the appearance of a 4JCF (and 5JCF for 6) coupling constant. We have shown that this effect is a through-space coupling.

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