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.