Assembly of high-nuclearity Sn26 , Sn34 -oxo clusters: solvent strategies and inorganic Sn incorporation.

A series of unprecedented high-nuclearity tin-oxo nanoclusters (up to Sn34 ) with structural diversity have been obtained. The characteristics of the applied solvents had great influence on the assembly of these Sn-O clusters. Pure alcohol environments only gave rise to small clusters of Sn6 , whilst the introduction of water significantly increased the nuclearity to Sn26 , which greatly exceeds those of the known tin-oxo clusters (≤14); the use of aprotic CH3CN finally produced the largest Sn34 to date. Apart from the nuclearity breakthrough, the obtained tin-oxo clusters also present new structural types that are not found in previous reports, including a layered nanorod-like structure of Sn26 and the cage-dimer structure of Sn34 . The layered Sn26 clusters represent good molecular models for SnO2 materials. Moreover, an electrode derived from TOC-17 with a {Sn26 } core shows better electrocatalytic CO2 reduction activity than that from TOC-18 with Sn34 . This work not only provides an efficient methodology for the rational assembly of high-nuclearity Sn-O clusters, but also extends their potential applications in energy conversion.