A Nuclear Magnetic Resonance Study of some 4-X-Substituted-2,6-Dinitroanisoles and Related Meisenheimer 1,3- and 1,1-Complexes

1972 ◽  
Vol 50 (21) ◽  
pp. 3558-3565 ◽  
Author(s):  
M. P. Simonnin ◽  
M. J. Lecourt ◽  
F. Terrier ◽  
C. A. Dearing

The structures of transient 1,3-complexes 2 and stable 1,1-complexes 3 formed by the reaction of methoxide ion with various 4-X-2,6-dinitroanisoles in DMSO-d6 are confirmed by n.m.r. spectroscopy. 13C satellites in the proton spectra of anisoles and 1,1-complexes have been used to obtain [Formula: see text] as well as 4JH–H in these symmetrical compounds.The chemical shifts of the ring protons in 1,3- and 1,1-complexes give some information concerning the influence of the substituent X on the delocalization of the negative charge. In anisoles and 1,1-complexes, [Formula: see text] of the ring protons are mainly dependent on the inductive effect of X. Furthermore, a linear relationship is observed in anisoles between the chemical shift as well as [Formula: see text] of the methoxyl protons and the Hammett σP constant of X, thus suggesting an identical geometry of these molecules at C-2,-1, and -6.


2001 ◽  
Vol 56 (3-4) ◽  
pp. 288-290 ◽  
Author(s):  
V. N. Mirny ◽  
V. V. Trachevski ◽  
T. A. Mimaya

Abstract The chemical shifts of Cs+ in binary melts of caesium trifluoroacetate with lithium, sodium, potassium or thallium trifluoroacetates have been studied as a function of composition. An influence of added foreign cations on chemical shift of caesium nuclei has been found. The nature of the intra-and intermolecular paramagnetic contributions into the shifts of 133Cs is discussed.



1982 ◽  
Vol 60 (24) ◽  
pp. 2987-3092 ◽  
Author(s):  
Barry J. Blackburn ◽  
Douglas W. Ankrom ◽  
Harold M. Hutton

Carbon-13 nmr chemical shift assignments are reported for a series of 5-substituted benzimidazoles, 2-methylbenzimidazole, and 5,6-dimethylbenzimidazole. By employing the three-parameter equation of Smith and Proulx, the chemical shifts of all the ring carbons of the 5-substituted compounds are correlated with F and R of Swain and Lupton and Q of Schaefer; only the ipso carbon, C-5, has chemical shifts with a correlation coefficient less than 0.953. These correlations are compared with those obtained from the Swain–Lupton and Taft relationships; in general those from the latter two approaches are found to be less satisfactory. Correlations of the same chemical shifts with excess charge density values, calculated at the INDO level of approximation, are also presented.



1988 ◽  
Vol 66 (12) ◽  
pp. 3003-3011 ◽  
Author(s):  
Richard E. Perkier ◽  
Michael J. Mcglinchey

The 500 MHz 1H and 125 MHz 13C spectra of ergosteryl and 7-dehydrocholesteryl acetate were recorded in C6D6 and CDCl3 and assigned using two-dimensional NMR techniques. It is shown that incorporation of an Fe(CO)3 or a Rh(acac) moiety onto the ring B diene system affects the chemical shifts of neighbouring protons and carbons. These changes are discussed in terms of the anisotropic properties of the organometallic fragments.



1993 ◽  
Vol 50 (2) ◽  
pp. 67-76 ◽  
Author(s):  
Richard A. Komoroski ◽  
Joseph E.O. Newton ◽  
Jay R. Sprigg ◽  
David Cardwell ◽  
Parekkat Mohanakrishnan ◽  
...  


1980 ◽  
Vol 58 (23) ◽  
pp. 2442-2446 ◽  
Author(s):  
G. W. Buchanan ◽  
F. G. Morin ◽  
R. R. Fraser

15N nuclear magnetic resonance chemical shifts and one-bond 15N—31P couplings are reported for a series of five N-arylphosphoramidates and four N-arylphosphorimidates. Results are interpreted in terms of an extensively delocalized N lone pair in the phosphoramidates, with pπ–pπ donation into the aromatic ring being dominant over pπ–dπ donation from nitrogen to phosphorus.



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