MOF-Triggered Synthesis of Subnanometer Ag 0 2 Clusters and Fe 3+ Single Atoms: Heterogenization Led to Efficient and Synergetic One-Pot Catalytic Reactions.

The combination of well-defined Fe 3+ isolated single-metal atoms and Ag 2 subnanometer metal clusters within the channels of a metal-organic framework (MOF) is reported and characterized by single-crystal X-ray diffraction for the first time. The resulting hybrid material, with the formula [Ag 0 2 (Ag 0 ) 1.34 Fe III 0.66 ]@Na I 2 {Ni II 4 [Cu II 2 (Me 3 mpba) 2 ] 3 }·63H 2 O ( Fe 3+ Ag 0 2 @MOF ), is capable of catalyzing the unprecedented direct conversion of styrene to phenylacetylene in one pot. In particular, Fe 3+ Ag 0 2 @MOF ─which can easily be obtained in a gram scale─exhibits superior catalytic activity for the TEMPO-free oxidative cross-coupling of styrenes with phenyl sulfone to give vinyl sulfones in yields up to >99%, which are ultimately transformed, in situ, to the corresponding phenylacetylene product. The results presented here constitute a paradigmatic example of how the synthesis of different metal species in well-defined solid catalysts, combined with speciation of the true metal catalyst of an organic reaction in solution, allows the design of a new challenging reaction.