Recombination of propargyl radicals to form benzene: A computational study

Abstract

Present study involves QCISD(T)/6-311G(d,p) level calcula­tions to analyze reaction pathways during the recombination of propargyl radicals leading to the formation of benzene. A new path on the C₃H₃ recombination potential energy surface that connects 3,4-dimethylenecyclobutene (34DMCB) to benzene involving four-membered bicyclic compounds such as bicycle­[2.2.0]hexa-1(4),2-diene and bicyclo[2.2.0]hexa-2,5-diene have been determined. Geometries of all the species are optimized at HF/6-31G(d) level. All the stationary points along this path on the potential energy surface have been characterized. Single point energy calculation have been performed using QCISD(T) with 6-311G(d,p) basis set. Transition states are determined and characterized by the observation of only one imaginary frequency. Intrinsic Reaction Coordinate (IRC) calculation has also been performed in order to ascertain the existence of the transition states.