Atomically\nPrecise Cu<sub>12</sub> Nanoclusters with\nThermally Activated Delayed Fluorescence Properties

Ligand-stabilized\nmetal nanoclusters with atomic precision\nare\nconsidered to be promising materials in the field of light-emitting\nand harvesting. Among these, nanoclusters with thermally activated\ndelayed fluorescence (TADF) properties are highly sought after. While\nseveral gold and silver nanoclusters with TADF properties have been\nreported in recent years, research on copper counterparts has significantly\nlagged behind. In this study, we present the synthesis, total structure\ndetermination, and photoluminescent properties of a copper cluster\nwith TADF properties. The cluster, with the molecular formula (PPh<sub>4</sub>)[Cu<sub>12</sub>(NO<sub>3</sub>)<sub>6</sub>(AdmS)<sub>6</sub>] (PPh<sub>4</sub> is tetraphenylphosphine tetraphenylboron, and\nAdmSH is adamantanethiol), was obtained in a single reaction in the\npresence of air and fully characterized using electrospray ionization\nmass spectroscopy (ESI-MS), X-ray photoelectron spectroscopy, nuclear\nmagnetic resonance, and ultraviolet–visible spectroscopy (UV–vis).\nThe molecular structure of the cluster, as determined by X-ray crystallographic\nanalysis, reveals the stabilization of a Cu<sub>12</sub> core (layer-by-layer\ngrowth mode of Cu<sub>3</sub>@Cu<sub>6</sub>@Cu<sub>3</sub>) with\n6 NO<sub>3</sub><sup>–</sup> and 6 AdmS<sup>–</sup> ligands\nacting as stabilizing ligands. Interestingly, the cluster exhibits\nphotoluminescence in both crystalline and solution states and displays\ntypical TADF characteristics within the temperature range of 163–243\nK. This study not only presents a pioneering example of copper nanoclusters\nwith TADF properties but also highlights the promising future of copper\nclusters in material science.