In situ insertion of copper to form heteroanionic D 3h -symmetric [Cu 3 Mo 8 O 32 ] 10- for a templated Ag 55 nanocluster.

A polyoxometalate-templated thiolate-protected silver nanocluster, [Cu 3 (Mo 4 O 16 ) 2 @Ag 55 (CyhS) 43 (CH 3 O)(COOCF 3 )]·3H 2 O, has been isolated under solvothermal conditions. In situ insertion of three Cu 2+ ions into two polymolybdate anions generated a new, sandwich-type D 3h -symmetric [Cu 3 (Mo 4 O 16 ) 2 ] 10- polyoxoanion template encapsulated into an Ag 55 (CyhS) 43 shell. The structure and composition of this Ag nanocluster have been fully characterized. This work has provided a new way to develop high-nuclearity metal nanoclusters with various structures.