Fluorine-containing counterions as catalysts triggering the size transformation of copper nanoclusters

Abstract

Fluorine-containing salts not only serve as common counterions for nanoclusters but also interact with cluster molecules, potentially driving their structural transformation. In this work, we successfully achieved the highly efficient size transformation from Cu₈ to Cu₁₁ nanoclusters using fluorine-containing counterion salts (NaSbF₆) as catalysts. Multiple characterization studies, including optical spectroscopy, ESI-MS, and ¹⁹F NMR, were employed to monitor the cluster transformation. The results indicate that the direct interaction between SbF₆⁻ counterions and Cu₈ nanoclusters is the main driving force behind the size transformation. More importantly, ESI-MS revealed the formation of (Cu₄)(SbF₆⁻)_y(Na⁺)_y (y ≥ 6) colloidal particles as intermediate products during the transformation. This work provides new insights into the interactions between fluorine-containing salts and nanoclusters.