Acid-Base-Triggered Structural Transformation of a Polyoxometalate Core Inside a Dodecahedrane-like Silver Thiolate Shell.

Self-assembly of metavanadate and organosilver(I) salts leads to a novel dodecahedrane-like [Ag30 ((t) BuS)20 ](10+) silver(I) thiolate nanocage that tightly wraps an unusual C2h polyoxovanadate anion. The polyoxovanadate core undergoes transformation to a D3d configuration upon acidification, and reverts back to its original C2h structure upon addition of base. Chromism was observed for the silver(I) thiolate cluster during the configurational change of the central polyoxovanadate core; the color of the solution changes reversibly from green to dark yellow. This work represents the first reported example of chromic polyoxometalate-templated silver(I) thiolate shells that respond to external acid-base stimuli. It also represents an important advance in providing crystallographic proof that structural transformations occur in a nanoscale core-shell cluster.