Bifunctional Copper Metal–Organic Framework Catalyst for Late-Stage Functionalization of Alkenes

Multifunctional catalysts in organic synthesis are highly attractive, particularly in the construction of complex molecules. In this work, we report a heterogeneous bifunctional Cu-based metal–organic framework (MOF) catalyst, IMU-108, serving as both a photoredox catalyst and a cross-coupling catalyst. IMU-108 was synthesized on a gram scale from Cu(NO3)2·3H2O and 5-mercaptoisophthalic acid precursors through a simple refluxing device. The structure of IMU-108 is formed via an in situ S–S bridge bond connecting zero-dimensional metal–organic polyhedra (MOPs), each composed of 12 Cu–Cu paddle-wheel motifs. These interpolyhedral S–S bonds result in a rigid geometric structure and ensure inner MOPs remain bench-stable while maintaining catalytic activity. We demonstrate the capacity of IMU-108 in heterogeneous photoredox-catalyzed cross-coupling of styrenes and α-bromo esters with boronic acids to yield various substituted 1,1-diaryl alkanes in a single step. The versatility of this method enables late-stage functionalization of complex molecules without the need for de novo synthesis. IMU-108 exhibits good reusability, maintaining its catalytic activity over ten consecutive reaction cycles. Furthermore, computational and mechanistic studies suggest that coordinatively unsaturated copper species on the surface of IMU-108 served as catalytically active sites, possessing competent Single-Electron Transfer (SET) reduction ability and facilitating cross-coupling reactions.