Photochemical Self-Transformation Approach for Constructing Copper-Selenide Nanoclusters

Copper nanoclusters are garnering significant scientific interest due to their distinctive structural characteristics, tunable electronic band structures, and distinct physicochemical properties. It is imperative in contemporary research to develop controllable and efficient synthetic strategies to facilitate the formation of the underlying structures of copper nanoclusters, particularly those with different compositions, structures, and functionalities. Reported herein is an approach involving the conversion of preexisting clusters into binary copper-selenide semiconductor nanoclusters that exhibit favorable properties. In this study, a Cu₈ cluster costabilized by benzyl-functionalized selenolate and phosphine ligands was synthesized using a one-pot method. The cluster was subsequently transformed into Cu₃₂ and Cu₃₄Cl₂ clusters upon exposure to light irradiation. These three clusters exhibit distinct structural features; notably, the Cu₃₂ core introduces selenium atoms that are not present in Cu₈, while the Cu₃₄Cl₂ core introduces both selenium and chlorine atoms in comparison to Cu₈. Despite these differences, all clusters maintain a common nucleosome-shell-ligand structure. The mechanism underlying this transformation, which involves free radicals, was postulated based on in situ ultraviolet-visible spectroscopy, electrospray ionization mass spectrometry, and electron paramagnetic resonance analysis. As a cocatalyst with TiO₂, these copper-selenide semiconductor nanoclusters exhibit high performance in photocatalytic hydrogen evolution. The insights gained from this study regarding photoradiation-induced self-transformation can facilitate future research endeavors aimed at developing more precise and controlled synthesis methodologies for functional copper nanoclusters.