McConnell-Robertson equation

Structural and stereo chemical information can be obtained by the application of the McConnell-Robertson equation [40]... 

The observed shifts did not obey the McConnell-Robertson equation. It has been found from 13C NMR that a contact (through-bond) mechanism was found to be significant in... 

Physical Properties of 1,2,3-Thiadiazoles. Lanthanide-induced shifts have been used for elucidation of the structure of thermally generated monoxides of 1,2,3-thiadiazoles ( H and C). A calculation has been developed for the evaluation of lanthanide-induced shifts according to the McConnell-Robertson equation. The o and Or parameters of triazoles were also determined by n.m.r. spectroscopy. ... 

If one wishes to extract stereochemical information about substrates in solution from the data obtained in the NMR experiments, two physical-mathematical models are available. For shifts induced by a dipolar (pseudocontact) mechanism, the McConnell-Robertson equation (Equation 1) (28, 29)—where r, i, and are the spherical polar coordinates of the ith resonating nucleus in the coordinate system of the principal magnetic axes—relates the direction and magnitude of the shift to the geometry of the substrate-chelate complex. If the substrate-chelate... 

Is exactly the same (for obvious reasons) as the McConnell-Robertson equation for the pseudo-contact shift produced by laq] haBlde substrates. This equation has now come to be accepted by the great majority of Investigations Into LIS and all the computer programmes written to deduce the correct position of the lanthanide atom from the observed shifts Incorporate the McConnell-Robertson equation. ... 

Thus the fact that the form of the equivalent dipole model is Identical to that of the McConnell-Robertson equation means that all the iterative LIS programmes may be applied without any modifications to the determination... 

The main use of NMR shift reagents was in the separation of overlapping multiplets in proton NMR spectra of organic compounds which are able to coordinate to a lanthanide ion. It is also possible to obtain information on the molecular structure in solution by fitting the dipolar contribution to the bormd shift of the complex between the shift reagent and the substrate to the so-cdlled McConnell-Robertson equation (McCotmell and Robertson, 1958). 

Only the pseudocontact shifts give exact information on the location of the cation, and, therefore, on the structure of the complex. According to an equation developed by McConnell and Robertson,the lanthanide-induced shift, Av, is... 

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