Aceanthracene-anthracene dimerization with the formation of an E-bridge bond.

The process of soot formation is one of the most complex combustion phenomena. However, the most important stage of soot formation is the poorly studied stage of nucleation, where young soot particles are formed from gas phase molecules. Revealing the process of soot nucleation will subsequently lead to the creation of kinetic mechanisms that describe the formation of soot in the smoking flame. Given the above, the study of the mechanisms of nucleation of soot is an urgent task. It is currently considered that the most likely mechanism for the particles nucleation is the nucleation through the formation of a strong chemical bond. The results of a theoretical study by A. Mebel and M. Frenklach, obtained by modern methods of computational chemistry, showed that the interaction of acepyrene and a pyrenyl radical leads to the formation of a PAH dimer via a so-called E-bridge bond, where the E-bridge bond is one common edge for the five-membered rings of two monomers. In this paper, we consider the formation of an E-bridge bond between the molecules of aceanthracene and anthracene. The geometry of the reactants, products, transition states, and intermediates were optimized at the DFT B3LYP theory level with the 6-31G** basis set. For the aceanthracene-anthracene system, dimerization due to the formation of an E-bridge bond can have several similar paths that differ in the position of the benzene rings in the starting monomers relative to each other. The formation of two main products is possible, each of which can be present in a cis and a trans configuration. Moreover, four possible paths practically do not differ in terms of the energies of the intermediates and transition states. [ABSTRACT FROM AUTHOR]