On the interpretation of linear correlations between nuclear magnetic resonance substituent chemical shifts and substituent reactivity parameters in benzene derivatives

Abstract

The currently poorly-understood relationships between n.m.r. substituent chemical shift (s.c.s) data and substituent reactivity parameters are reconsidered within the framework of a substantially modified version of the usual general theory for structure–property relationships, that has recently been proposed. Predictions concerning the circumstances under which quantitative linear correlations of two kinds should or should not occur are confirmed for compounds which are formally substituted benzenes. It is concluded that the theory merits consideration in the theoretical treatment of any case of a structure–property or an interproperty relationship. The implications for the use of n.m.r. s.c.s. data to obtain structural information about molecular systems are briefly discussed.