Three in one: Three different molybdates trapped in a thiacalix arene protected Ag72 nanocluster for structural transformation and photothermal conversion

Abstract

Polyoxometalates (POMs) represent crucialintermediates in the formation of insoluble metal oxidesfrom soluble metal ions, however, the rapid hydrolysis-condensation kinetics of MoVI or WVI makes the directcharacterization of coexisted molecular species in agiven medium extremely difficult. Silver nanoclustershave shown versatile capacity to encapsulate diversePOMs, which provides an alternative scene to appreciatelandscape of POMs in atomic precision. Here, we reporta thiacalix[4]arene protected silver nanocluster (Ag72b)that simultaneously encapsulates three kinds of molyb-dates (MoO42 , Mo6O228 and Mo7O258 ) in situ trans-formed from classic Lindqvist Mo6O192 , providing moredeep understanding on the structural diversity andcondensation growth route of POMs in solution. Ag72bis the first silver nanocluster trapping so many kinds ofmolybdates, which in turn exert collective templateeffect to aggregate silver atoms into a nanocluster. Thepost-reaction of Ag72b with AgOAc or PhCOOAgproduces a discrete Ag24 nanocluster (Ag24a) or an Ag28nanocluster based 1D chain structure (Ag28a), respec-tively. Moreover, the post-synthesized Ag28a can beutilized as potential ignition material for further applica-tion. This work not only provides an important modelfor unlocking dynamic features of POMs at atom-preciselevel but also pioneers a promising approach to synthe-size silver nanoclusters from known to unknown.