Discovering Novel Gas-Phase N-Heterocycle Formation Pathways with an ab initio Nanoreactor

Abstract:

Titan's atmosphere is made up primarily of nitrogen and methane, with a large variety of more complex organic molecules revealed by the Cassini-Huygens mission. This variety likely includes nitrogen-containing heterocycles, which are of particular interest to astrobiology. Previous studies have shown that N-heterocycles can readily form in the gas-phase through radical-neutral processes, which are thought to occur in Titan's atmosphere. Here, we seek to expand on previous studies of N-heterocycle formation through ab initio molecular dynamics simulations. These simulations were performed with an ab initio nanoreactor, a computational tool developed for chemical discovery. Multiple novel gas-phase N-heterocycle formation pathways have been revealed, and many reactants are similar to molecules previously identified in Titan's atmosphere. The results also reinforce previous experimental and theoretical studies which demonstrated that smaller single-ring N-heterocycles are potential precursors to larger single-ring ones. The nonintuitive N-heterocycle precursors revealed by this work warrant further experimental and theoretical study and possible reexamination of the results of the Cassini-Huygens flyby.