Photoelectron Spectroscopy and Theoretical Studies of Ge 6 MnO - Cluster with a Mn V ≡O Unit Interacting with a Double Aromatic Ge 6 4- Ligand.

The structures and chemical bonding of Ge 6 MnO - are investigated using anion photoelectron spectroscopy and theoretical calculations. The lowest energy structure of Ge 6 MnO - is found to have a C 5v symmetric structure with an O atom attached to a pentagonal bipyramidal MnGe 6 . Chemical bonding analyses reveal that Ge 6 MnO - can be considered as a [Mn V ≡O] 3+ [Ge 6 4- ] complex with two unpaired 3d electrons on Mn. The Ge 6 4- ligand is highly stable in Ge 6 MnO - and exhibits double aromaticity with 10 delocalized σ electrons and 6 delocalized π electrons. Our calculations show that the Ge 6 4- ligand could also form [Cr IV ≡O] 2+ [Ge 6 4- ] in Na 2 Ge 6 CrO and [Fe IV ≡O] 2+ [Ge 6 4- ] in Na 2 Ge 6 FeO. The results suggest the possibility of designing and synthesizing a series of stable high-valent metal oxide anionic species with the composition [M≡O] n+ [Ge 6 4- ] in the gas phase or in the salt-stabilized bulk solid materials.