To understand anion formation mechanisms, we studied the reactions of neutral MAO species with OMTS, which generate [Me2Al(OMTS)][n,m] ion-pairs in fluorobenzene medium during ESI-MS experiments. We initially considered the two reaction pathways shown in Scheme 1, yielding separated, non-interacting ions in the gas phase. Using M06-2X, we computed gas-phase electronic energy changes for every unique aluminum site (Figure ) in each MAO structure listed in Table . This comprehensive analysis required over 300 individual calculations, as each site was evaluated for both possible ionization mechanisms. The complete results, including neutrals and their corresponding anions shown in consistent orientations, are provided in Supporting Information Table S-2, along with their respective reaction energies.