Empirically corrected ab initio calculation of proton NMR chemical shifts of antiaromatic hydrocarbons

Five empirical fixes for the failure are developed. Each markedly improves the fit of the antiaromatic NMR proton shifts. The best of them, based on graph theory, gives a standard deviation of only 0.10 ppm for the 16 antiaromatic proton shifts, a standard deviation of 0.05 ppm for the 19 aromatic proton shifts, and a standard deviation of 0.14 ppm for the combined set of 196 proton shifts.