Estimation of C−C Bond Dissociation Enthalpies of Large Aromatic Hydrocarbon Compounds Using DFT Methods

Four density-functional methods (B3LYP, B3PW91, MPW1PW91, and B3P86) are employed to compute the C−C homolytic bond dissociation enthalpies (BDE) of a set of aromatic hydrocarbons related to coal structures with aliphatic linkages. In comparison with the available experimental data, the B3P86 method can provide reasonably reliable BDE values for these model compounds. The BDE values for large aromatic hydrocarbon systems of interest are computed, and the substituent effects are discussed.