Electron transfer as a probe for relativistic effects in the ionization of atoms: Onset of electron transfer from benzene to heavy Group 11 and 12 transition metal cations

Abstract

Mass spectrometric ICP-SIFT measurements are reported for the kinetics and product formation in reactions of Group 11 and Group 12 atomic cations with benzene, as well as hexafluorobenzene and carbon disulfide, all at 298 K in helium at 0.35 Torr. Ligation is observed to dominate with the lighter ions in these two triads, but electron transfer emerges dramatically with the third-row cations Au+ and Hg+. The latter is attributed to relativistic effects in the ionization energies of Au and Hg as predicted by quantum chemical calculations of non-relativistic and relativistic valence shell s-electron energies that render electron transfer thermoneutral or exothermic.