Structural and Bonding Insights into B$_8$Cu$_3^-$ Clusters: A DFT Study

In this study, we employ density functional theory (DFT) to investigate the structural and electronic properties B$_8$Cu$_3^-$ clusters -- boron-based frameworks doped with three copper atoms. The results indicate that the lowest-energy structure features a vertical Cu$_3$ triangle supported on a B$_8$ wheel geometry, whereas the horizontally supported configuration is 3.0 (5.6) kcal/mol higher in energy at the PBE0 ($\omega$B97X) functional. Electron localization function (ELF) and Mulliken population analyses reveal that the most stable isomer exhibits strong Cu-B interactions and significant electron delocalization, which contribute to its enhanced stability. Localized orbital locator (LOL) maps further support this finding by showing pronounced electron localization around the Cu$_3$ unit in the more stable structure. These insights highlight the possible role of Cu-centered multicenter bonding in stabilizing boron-based nanoclusters.