Rational Design of Highly Phosphorescent Nanoclusters for Efficient Photocatalytic Oxidation

Abstract

Analyzing the molecular structure-photophysical property correlations of metal nanoclusters to accomplish function-oriented photocatalysis could be challenging. Here, the selective heteroatom alloying has been exploited to a <b>Au</b>_<b>15</b> nanocluster, making up a structure-correlated nanocluster series, including homogold <b>Au</b>_<b>15</b>, bimetallic <b>Ag</b>_{<b><i>x</i></b>}<b>Au</b>_{<b>15-<i>x</i></b>} and <b>Cu</b>_{<b><i>x</i></b>}<b>Au</b>_{<b>15-<i>x</i></b>}, trimetallic <b>Ag</b>_{<b><i>x</i></b>}<b>Cu</b>_{<b><i>y</i></b>}<b>Au</b>_{<b>15-<i>x</i>-<i>y</i></b>}, and tetrametallic <b>Pt</b>_<b>1</b><b>Ag</b>_{<b><i>x</i></b>}<b>Cu</b>_{<b><i>y</i></b>}<b>Au</b>_{<b>15-<i>x</i>-<i>y</i></b>}. Their structure-dependent photophysical properties were investigated due to the atomically precise structures of these nanoclusters. Cu-alloyed <b>Cu</b>_{<b><i>x</i></b>}<b>Au</b>_{<b>15-<i>x</i></b>} showed intense phosphorescence and the highest singlet oxygen production efficiency. Moreover, the generation of ¹O₂ species from excited nanoclusters enabled <b>Cu</b>_{<b><i>x</i></b>}<b>Au</b>_{<b>15-<i>x</i></b>} as a suitable catalyst for efficient photocatalytic oxidation of silyl enol ethers to produce α,β-unsaturated carbonyl compounds. The generality and applicability of the <b>Cu</b>_{<b><i>x</i></b>}<b>Au</b>_{<b>15-<i>x</i></b>} catalysts toward different photocatalytic oxidations were assessed. Overall, this study presents an intriguing <b>Au</b>_<b>15</b>-based cluster series enabling an atomic-level understanding of structure-photophysical property correlations, which hopefully provides guidance for the fabrication of cluster-based catalysts with customized photocatalytic performance.