Tetraphenylethene-Based Ni8-Pyrazolate Metal-Organic Framework for Photoredox/Nickel Dual Catalysis of C-S Cross-Coupling.

Abstract

As a prototypical aggregation-induced emission luminogen (AIEgen), the tetraphenylethene (TPE) moiety has been judiciously modified as organic linkers for constructing various functional metal-organic frameworks (MOFs). However, these AIEgen-based MOFs have rarely received research attention in photocatalytic applications due to their limited stability in harsh reaction conditions. In this work, we report a robust Ni8-pyrazolate-based MOF (denoted as TPE4Pz-Ni) under the guidance of reticular chemistry, which is assembled by an AIE-active tetratopic linker of 1,1,2,2-tetrakis(4-(1H-pyrazol-4-yl)phenyl)ethane (H4-TPE4Pz) with a 12-connected Ni8-cluster of [Ni8(OH)4(H2O)2Pz12] (Pz = pyrazolate) in a (4,12)-connected ftw-a topological network. Notably, MOF TPE4Pz-Ni exhibits excellent stability in a wide range of solvents and even in a saturated NaOH solution. Moreover, its luminescent emission is effectively quenched via a ligand-to-metal charge transfer (LMCT) process originating from the TPE-cored linker to the Ni8 cluster, which enables TPE4Pz-Ni to act as an efficient photoredox/nickel dual catalyst for light-mediated C-S cross-coupling reactions between various aryl iodides and thiols.