Correlations of proton coupling constants in mono- and di-substituted ethylenes with the inverse of substituent electronegativities. A reconsideration of previous correlations
It is shown that in mono- and di-substituted ethylenes the cis, trans, and geminal proton–proton coupling constants correlate with the inverse of the sum of the substituent electronegativities (one of the substituents may be hydrogen). Previous correlations indicated a direct negative proportionality between the two parameters. This was due to the restricted range of electronegativities over which the correlations were made. There appear to be no strong theoretical objections to the inverse proportionality between coupling constants and substituent electronegativities discussed in this paper.