Density functional and Moller-Plesset perturbation approaches were applied to charge-remote fragmentation along the reaction coordinate of 1,4-hydrogen eliminations in the gas-phase. The mechanisms and energy barriers of the reactions are discussed. The calculations indicate that 1,4-hydrogen elimination via an aromatic-like six-atom transition state structure is energetically favorable with no involvement of the charge site. Cleavage of C-C and C-H bonds and the formation of H-H bonds occur simultaneously, and the energy barrier of this reaction is 4.01 eV. Energy decomposition analysis predicts a repulsive interaction between the formed H-2 and the remaining substituents. (C) 2017 Elsevier B.V. All rights reserved.