Transforming Ni₉Te₆ from Electron Donor to Acceptor via Ligand Exchange

The ability to donate or accept charge is a fundamental property of a chemical species. This property is typically rooted in the valence electron count and may be determined from the ionization potential and electron affinity. First-principles theoretical studies have been carried out to show that a cluster may be transformed from a donor to an acceptor by changing only the ligand. Our studies on a chalcogenide Ni₉Te₆ cluster show that the ionization potential and electron affinity undergo substantial changes as the attachment of phosphine PH₃ decreases the ionization potential to be less than that of sodium, whereas the attachment of PCl₃ or CO increases the adiabatic electron affinity to be greater than iodine. The ligands change the electronic properties by creating a coulomb well that can shift the electronic spectrum. Studies on Co₉Te₆(CO)₈ clusters show agreement with experiment and demonstrate that the ideas developed here are applicable to a wider group of clusters