Nanocluster Transformation Induced by SbF<sub>6</sub><sup>–</sup> Anions toward Boosting Photochemical Activities
Xiao Wei, Kenneth Chu, Jonathan R. Adsetts, Hao Li, Xi Kang, Zhifeng Ding, Manzhou Zhu
Abstract
The interactions between SbF6– and metal nanoclusters are of significance for customizing clusters from both structure and property aspects; however, the whole-segment monitoring of this customization remains challenging. In this work, by controlling the amount of introduced SbF6– anions, the step-by-step nanocluster evolutions from [Pt1Ag28(S-Adm)18(PPh3)4]Cl2 (Pt1Ag28–Cl) to [Pt1Ag28(S-Adm)18(PPh3)4](SbF6)2 (Pt1Ag28–SbF6) and then to [Pt1Ag30Cl1(S-Adm)18(PPh3)3](SbF6)3 (Pt1Ag30–SbF6) have been mapped out with X-ray crystallography, with which atomic-level SbF6– counterion effects in reconstructing and rearranging nanoclusters are determined. The structure-dependent optical properties, including optical absorption, photoluminescence, and electrochemiluminescence (ECL), of these nanoclusters are then explored. Notably, the Pt1Ag30–SbF6 nanocluster was ultrabright with a high phosphorescence quantum yield of 85% in N2-purged solutions, while Pt1Ag28 nanoclusters were fluorescent with weaker emission intensities. Furthermore, Pt1Ag30–SbF6 displayed superior ECL efficiency over Pt1Ag28–SbF6, which was rationalized by its increased effectively exposed reactive facets. Both Pt1Ag30–SbF6 and Pt1Ag28–SbF6 demonstrated unprecedented high absolute ECL quantum efficiencies at sub-micromolar concentrations. This work is of great significance for revealing the SbF6– counterion effects on the control of both structures and luminescent properties.