Recent progress in functional atom-precise coinage metal clusters protected by alkynyl ligands

The selection of surface organic ligands is very important for the preparation of coinage metal clusters with precise structures, which can dictate the related properties of metal clusters. Alkynyl ligands, as a class of protecting ligands in metal cluster systems, have been gaining attentions because of the characteristics of both π and σ coordination modes. Specially, alkynyl-protected coinage metal clusters possess rich properties. However, there is no review to systemically summarize the functional properties and structure-functionality correlations of alkynyl-protected coinage metal clusters. In this review, the development of alkynyl ligands for the preparation of coinage metal clusters was reviewed. Additionally, the synthetic approaches of the alkynyl-protected coinage metal clusters were provided. Then, the functional properties of the alkynyl-protected coinage metal clusters were comprehensively summarized. In the end, the prospects and opportunities for the future development were discussed. We believed that the review will motivate the development of functionality-oriented alkynyl-protected coinage metal clusters.