Neutral and charged Fe130, Fe13+, and Fe13¿ magnetic clusters as activator species for carbon monoxide. A density functional theory analysis
Academic Article in Scopus
The dissociation of CO on neutral and charged Fe¿¿0,± magnetic clusters was investigated using DFT. Following full geometry optimizations, all clusters adopted slightly distorted icosahedral geometries. Structures feature an antiferromagnetically coupled central iron atom, where significant charge localizes, surrounded by twelve surface atoms interacting with CO. Upon CO adsorption and subsequent cleavage, minor relaxations of the icosahedral framework occur. Reaction mechanism is governed by Fe¿¿0,± ¿ CO back-donation from cluster d-derived HOMO to CO antibonding ¿* LUMO, as confirmed by molecular orbital and NBO analyses. Bonding descriptors, including Wiberg Bond Indices and Natural Atomic Orbital bond orders, track the progressive weakening of C¿O bond along the reaction pathway. Reaction energetics reveal that all clusters activate CO, with the dissociated C¿Fe¿¿¿O product stabilized by up to ¿1.616 eV relative to separated species. The lowest activation barrier (2.431 eV) corresponds to the anionic pathway, highlighting the enhanced reactivity of negatively charged clusters.
