The structural dependence of the inductive effect. Part III. The calculation of geminal substituent effects upon 1H and 13C chemical shifts, and directly-bonded substituent effects upon 13C, 11B, 31P, and 119Sn shielding

Abstract

The calculational procedure applied in Part I to ¹⁹F shielding is extended to other nuclei. Substituent effects caused by directly bonded interactions are allowed for, in addition to geminal effects.

The method enables the chemical shifts of ¹H, ¹³C, ¹¹B, and ³¹P nuclei in a variety of situations to be calculated (from suitable references), and successfully explains deviations from additivity of substituent effects. An important exception is noted for the case of ¹¹⁹Sn shielding in some mixed halides of Sn^IV.