Abstract
The effect of substituents on proton chemical shifts has been analysed in terms of magnetic anisotropy and electrical field effect contributions and reasons are given for the necessity for detailed statistical analyses. By using data in the literature statistical information is given by which the success of such analyses can be judged for the effect of the carbonyl, the ethylenedioxy, the ethylenedithio and the cyano group, and the CH, CC, and CC bond. Frequently the inter-correlation coefficients of pairs of the explanatory variables used are large and the data are not statistically suitable for producing reliable values of magnetic anisotropy and electric-field effect constants. The magnetic anisotropy of the CH bond(s) replaced by the substituent is insignificant in these analyses. The electric-field effect is greater for measurements in deuteriochloroform than for measurements in carbon tetrachloride or cyclohexane.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have