Release of Neutrals in Electron-Induced Ligand Separation from MeCpPtMe₃: Theory Meets Experiment

The interest in the electron impact-induced ligand release from MeCpPtMe₃ [trimethyl(methylcyclopentadienyl)platinum(IV)] is motivated by its widespread use as a precursor in focused electron and ion beam nanofabrication. By experimentally studying the electron impact dissociative ionization of MeCpPtMe₃ under single-collision conditions, we have found that the removal of two methyl radicals is energetically more favorable than the removal of one radical and even energetically comparable to the nondissociative ionization of MeCpPtMe₃. This observation is explained by the structural rearrangement of the MeCpPtMe₃⁺ ion prior to dissociation, resulting in the removal of ethane instead of two methyl groups. This fragmentation pathway is computationally confirmed and studied by irradiation-driven molecular dynamics (IDMD) simulations. The formation of complex molecules in irradiation-induced molecular dissociation is a general phenomenon that can occur in various molecular systems. This study explains the puzzling results of previous experiments with MeCpPtMe₃ molecules and highlights the use of the IDMD approach to describe radiation-induced chemical transformations in molecular systems.