Infrared intensities as a quantitative measure of intramolecular interactions. Part XXXVII. 1,1-Disubstituted ethylenes

Abstract

Infrared intensities of the ν(CC) vibration of 1,1-disubstituted ethylenes are proportional to the sum of the squares of the σ⁰_R constants of the substituents. This result is rationalised in terms of the contributions of the substituents to the rate of change of dipole moment with normal co-ordinate. CNDO/2 MO calculations of charge densities and intensities are also reported.