Substituent effects and local molecular shape correlations

Using a detailed electron density shape analysis methodology, a new method is proposed for studying the main components of substituent effects in a series of disubstituted benzenes, in correlation with their activating and deactivating characteristics as observed by the induced shape changes of a local electron density cloud. The numerical measures obtained for the extent of shape changes can be correlated with known and with some unexpected effects of various substituents. The insight obtained from the shape analysis provides a theoretical, electron density based justification for some well-known trends, but it also provides new explanations for some of the unexpected features of these substituent effects.