A study of the π-polarisation effect: 13C nuclear magnetic resonance chemical shifts and SCF electron populations in 1-substituted 4-phenylbicyclo[2.2.2]octanes

Abstract

Substituent effects on the ¹³C chemical shifts and SCF electron populations of the aromatic carbon atoms of a series of 1-substituted 4-phenylbicyclo[2.2.2]octanes have been determined. With this data and similar ¹³C SCS and ¹⁹F SCS data from the literature a model for the π-polarisation effect has been developed which provides a simple unified rationalisation of ¹³C and ¹⁹F SCS in systems in which the substituent is not directly attached to an aromatic ring.