STATISTICAL DETERMINATION OF NMR COUPLING - ELECTRONEGATIVITY CORRELATIONS IN MONOHALO- AND DIHALOBENZENES

Statistical methods have been used to establish the best linear correlations between proton-proton couplings and substituent electronegativity values for the monohalobenzenes and 35 dihalobenzenes, involving a total of 133 distinct couplings. The results indicate that in meta and para disubstituted compounds, the substituent effects are both transferable and additive to a good approximation. In the ortho dihalobenzenes, however, substituent effects on the adjacent vicinal couplings are additive but not transferable from the other compounds. In general, the parameters obtained provide a basis for predicting trial values of couplings in structurally similar halogen derivatives. The general procedure employed is potentially applicable to other series of compounds. The substituent effects determined here have also been discussed briefly, particularly with regard to the geometrical and structural factors involved. © 1969, American Chemical Society. All rights reserved.