A Mn–Rh dual single-atom catalyst for inducing C–C cleavage: relay catalysis reversing chemoselectivity in C–H oxidation

The integration of two entirely unrelated organic reactions into a novel reaction poses a formidable challenge. While diatomic catalysts (DACs) have exhibited promise as a framework for realizing this concept, the fusion of disparate organic reactions using DACs remains exceptionally uncommon. The reason for this is that there are often interactions between the two metal sites in DACs, which create new difficulties in catalyst design for already complex reaction systems. Based on this situation, the incorporation of two completely isolated single-atom catalytic systems into the same reaction is a promising solution. Herein, we synthesized a Mn-Rh dual single-atom catalyst (DSAC, Mn₁-Rh₁@O-TiC) and this DSAC demonstrates remarkable selectivity and conversion efficiency in the oxidation reaction of cumene, facilitating the highly efficient production of acetophenone (AP) in an almost quantitative form. The two completely isolated metal catalytic centers, Mn and Rh, each playing a distinct role in the reaction, synergistically propel the directed conversion of cumene to AP in a well-defined manner. This investigation not only illustrates a rare instance of dual single-atom catalyst-mediated relay catalysis in organic synthesis but also imparts valuable insights into the systematic design of catalytic systems for organic tandem reactions, approached from the vantage point in the atomic scale.