Exploring structures of small anionic nickel-ethanol clusters with infrared spectroscopy

Small anionic nickel clusters with ethanol are investigated with a combination of mass-selective infrared photodissociation spectroscopy in a molecular beam and density functional theory simulations at the BLYP/6-311g(d,p) and TPSSh/def2-TZVPP level. In this context, the O-H stretching vibration of the ethanol is analyzed to obtain information about the structural motif, the geometry of the metal core, and the spin state of the clusters. For the [Ni₂(EtOH)]⁻ and [Ni₃(EtOH)]⁻ clusters, we assign quartet states of motifs with a hydrogen bond from the ethanol to the linear nickel core. The aggregation of a further ethanol molecule, yielding the [Ni₃(EtOH)₂]⁻ cluster, results in the formation of a cooperative hydrogen bond network between the nickel core and the two ethanol molecules.