Abstract: | Fifty-seven values for the ortho-benzylic coupling constant 4JMe? C?C? H (henceforth denoted as 4JOB) were obtained for a variety of heteroaromatic systems. It was shown that a good correlation exists between 4JOB when the methyl group is not α to the heteroatom and the SCF-MO bond order. This method can therefore be used as an experimental means of determining bond orders in heteroaromatic systems. An examination of bond alternation in thirteen heteroaromatic systems has given a measure of relative “degree of aromaticity” for a larger number of systems than previously reported by any single method. |