Pure Quadrupole Resonance Determinations of Molecular Charge Distributions. I. Substituted Quinones, Quinolines, Pyridines, Pyrimidines, and Triazines

The charge distributions in quinone and several heterocyclics containing nitrogen in the ring have been determined from the pure quadrupole resonance frequencies of attached halogens. Agreement with values from molecular orbital calculations is good in quinone and pyridine but poor in quinoline. Quantitative measurements are presented for the effect of ring nitrogens on the double bond character of carbon-halogen bonds.