A Vitamin B 12 -Inspired Cobalt-Dye Coordination Polymer for Photocatalytic Directional Transportation of Electrons and Hydrogen

The directional transfer of electrons and hydrogen is of profound importance to the functions of enzymes such as vitamin B12 (VB12), offering bioinspired opportunities to address the pending issues in photocatalysis. Nevertheless, the direct biomimicry of VB12 in artificial catalytic systems remains a significant challenge. Herein, we report the integrated mimicry of the VB12-dependent dehalogenase and photoreceptor protein CarH by designing a luminescent cobalt-dye coordination polymer (CP) with an anisotropic electronic structure and a switchable ligand field. The well-tuned confined excited electrons of the framework enable the directional cascade electron transfers among ligands, nodes, and substrates. The ligand field of cobalt nodes could be modulated via ligand exchange to switch on the activation of cobalt−H sites. These synergistic regulations achieve potent photoreduction of inert substrates and subsequent cobalt−H catalysis, as verified by the hydroarylation probe reaction of aryl olefins with exclusive Markovnikov selectivity. Through directional, multistep translocations of hydrogen/carbon-centered radicals during chain-walking processes, the functionalization of aliphatic olefins is further achieved in a value-added, remote, regiospecific manner. The proposed mechanism is supported by experimental and theoretical density functional theory studies. This work presents a strategy not only biomimicking but also going beyond the natural VB12-enzymes.