Three in One: Three Different Molybdates Trapped in a Thiacalix[4]arene Protected Ag72 Nanocluster for Structural Transformation and Photothermal Conversion

Abstract Polyoxometalates (POMs) represent crucial intermediates in the formation of insoluble metal oxides from soluble metal ions, however, the rapid hydrolysis‐condensation kinetics of Mo VI or W VI makes the direct characterization of coexisted molecular species in a given medium extremely difficult. Silver nanoclusters have shown versatile capacity to encapsulate diverse POMs, which provides an alternative scene to appreciate landscape of POMs in atomic precision. Here, we report a thiacalix[4]arene protected silver nanocluster ( Ag72b ) that simultaneously encapsulates three kinds of molybdates (MoO 4 2− , Mo 6 O 22 8− and Mo 7 O 25 8− ) in situ transformed from classic Lindqvist Mo 6 O 19 2− , providing more deep understanding on the structural diversity and condensation growth route of POMs in solution. Ag72b is the first silver nanocluster trapping so many kinds of molybdates, which in turn exert collective template effect to aggregate silver atoms into a nanocluster. The post‐reaction of Ag72b with AgOAc or PhCOOAg produces a discrete Ag 24 nanocluster ( Ag24a ) or an Ag 28 nanocluster based 1D chain structure ( Ag28a ), respectively. Moreover, the post‐synthesized Ag28a can be utilized as potential ignition material for further application. This work not only provides an important model for unlocking dynamic features of POMs at atom‐precise level but also pioneers a promising approach to synthesize silver nanoclusters from known to unknown.