Uncatalyzed 1,4-hydrogenation of polycyclic aromatic hydrocarbons: A computational study

Quantum chemistry calculations have been used to study the 1,4-hydrogenation reactions of selected polycyclic aromatic hydrocarbons. We find that the geometric parameters associated with the transition structures are consistent with the Hammond postulate. In addition, the hydrogenation barriers vary linearly with the reaction energy, consistent with the Bell-Evans-Polanyi (BEP) principle. The regiochemistry for the hydrogenation of polycyclic aromatic hydrocarbons may be broadly predicted by examining the extent of disruption to aromaticity for the various possible hydrogenation pathways, or in finer detail by utilizing the BEP relationship.