Exploring the Structural, Electronic, and Chemical Bonding Properties of Ge₃C₃ ^- and Ge₃C₄ ^- Clusters via Theoretical...

We report a quantum chemical theoretical study on the structural, electronic, and chemical bonding properties of Ge₃C₃ ^-/0 and Ge₃C₄ ^-/0 clusters. We find that Ge₃C₃ ^- and Ge₃C₄ ^- contain one CCC and one CCCC unit, with one C terminal bonding with a Ge atom and another C terminal interacting with two additional Ge atoms forming a Ge₂C three-membered ring, respectively. Ge₃C₃ has a GeC₃ trigonal pyramidal and two Ge₂C₂ tetrahedral units. Ge₃C₄ possesses a hexagonal pyramidal structure containing a Ge₂C₄ six-membered ring. The vertical detachment energies (VDEs) are predicted to be 2.10 eV for Ge₃C₃ ^- and 2.40 eV for Ge₃C₄ ^- at the CCSD-(T) level, and the theoretical photoelectron spectra are simulated. Adaptive natural density partitioning (AdNDP) analyses indicate that the top C atom of the CCC unit in Ge₃C₃ ^- bonds with a Ge atom via a Ge-C σ bond, while another C terminal interacts with two Ge atoms via a 3c-2e σ bond, and there are two 6c-2e π bonds and one 6c-1e π bond delocalizing all atoms. The CCCC unit in Ge₃C₄ ^- bonds with the top Ge atom forming a Ge-C σ bond, two 5c-2e π bonds, and one 5c-1e π bond, with another two Ge atoms resulting in one Ge-C σ bond and one 3c-2e π bond.