Table 4: Thermodynamic parameters for different tautomers (kcal/mol) at B3LYP/6-31+G(d) in water.


PC13.5310.6582.02122.773
PC20.1770.1220.1370.275
PC30.0000.0000.0000.000
PC427.93623.99925.90425.843
PC528.03523.88725.91925.612
PC626.04822.52624.15924.496
PC726.19322.51024.22924.550
PC816.90210.06713.40413.409
PC919.17811.99415.52815.411
PC105.5152.2033.8243.970
PC110.1770.1260.1370.287
PC120.0000.0000.0000.000
PC1325.95322.16723.99024.103
PC1426.64822.72724.61724.804
PC1524.02520.72222.22322.721
PC1624.61321.24522.77323.353

Uncorrected energy;  bcorrected for zero-point and thermal energy.