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.

The metal nuclear magnetic resonance spectra of some tin(II) and lead(II) complexes with polydentate phosphines

1983 ◽  
Vol 61 (8) ◽  
pp. 1795-1799 ◽  
Author(s):  
Philip A. W. Dean
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nmr Spectra ◽  
Narrow Range ◽  
Chemical Shifts ◽  
Nuclear Magnetic Resonance Spectra ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The previously reported 1:1 complexes formed in MeNO2, between M(SbF6)2 (M = Sn or Pb) and Ph2P(CH2)2PPh2, PhP[(CH2)2PPh2]2, MeC(CH2PPh2)3, P[(CH2)2PPh2]3, and [Formula: see text] have been studied by metal (119Sn or 207Pb) nmr. The metal chemical shifts span the comparatively narrow range of −586 to −792 ppm and 60 to −269 ppm, relative to the resonance of MMe4, for 119Sn and 207Pb nmr, respectively. The implications of these data regarding the denticity of the ligand in M(P[(CH2)2PPh2]3)2+ are discussed, and a comparison with the metal nmr spectra of related stannous and plumbous complexes is made.

15N Nuclear Magnetic-Resonance Spectra of ortho-Substituted Phenylacetanilides: The Origin of γ-syn Effects

1989 ◽  
Vol 42 (4) ◽  
pp. 463 ◽  
Author(s):  
C Yamagami ◽  
N Takao ◽  
Y Takeuchi
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Aromatic Ring ◽  
Chemical Shifts ◽  
Van Der Waals ◽  
Side Chains ◽  
Upfield Shift ◽  
Nuclear Magnetic Resonance Spectra ◽  
The Difference ◽  
Magnetic Resonance Spectra

The 15N chemical shifts of X α and Y α, i.e., the nuclei through which the side chains, X and Y, respectively, of o-substituted phenylacetanilides (2a) are bonded to the aromatic ring were determined. There was observed a uniform upfield shift (γsyn effect). In order to explore the origin of the γ effect, other o-disubstitutes benzenes (2b-d) were also examined. The values of D, defined as the difference between γ α substituent chemical shifts of the ortho (2) and para (3) series of compounds, and considered as a measure of the γ-syn effect, were correlated with various electronic and steric substituent parameters. Correlations with electronegativity and van der Waals terms were successful. Examination of the correlations indicated that the γ-syn effect is mostly governed by electronegativity. The classic steric compression theory does not seem very convincing as a means of explaining the shielding γ-syn effect observed in the present study.

13C N.M.R. STUDIES: VIII. 13C SPECTRA OF SOME SUBSTITUTED ANISOLES

1966 ◽  
Vol 44 (23) ◽  
pp. 2855-2866 ◽  
Author(s):  
K. S. Dhami ◽  
J. B. Stothers
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Aromatic Ring ◽  
Steric Hindrance ◽  
Steric Effect ◽  
Chemical Shifts ◽  
Methoxyl Group ◽  
Side Chains ◽  
Nuclear Magnetic Resonance Spectra ◽  
Magnetic Resonance Spectra

The 13C nuclear magnetic resonance spectra of a series of 40 substituted anisoles have been obtained to investigate the effects of substitution on the aromatic and methoxyl carbon shieldings. This work extends our studies on the variations of chemical shifts of carbon nuclei in side chains of aryl derivatives. The question of steric hindrance to conjugative interaction of a methoxyl group with an aromatic ring is considered on the basis of the present results. Evidence of a steric effect in compounds in which both ortho positions are substituted is presented.

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