Acid-Induced Structural Diversity of Stable Mn(II) Metal–Organic Framework Photocatalysts for Effective Visible Light-Driven C–H Direct Trifluoromethylation

Rational structural engineering of metal-organic frameworks (MOFs) through dimensionality modulation enables the precise tailoring of light-matter interactions and reaction kinetics. Herein, we successfully obtained a one-dimensional (1D) metal-organic chain (MOC) with [Mn(<b>ADBA</b>)(DMA)]_<i>n</i> (<b>XAIU-2</b>) and a three-dimensional (3D) metal-organic framework (MOF) with [Mn(<b>ADBA</b>)(H₂O)(DMA)]_<i>n</i> (<b>XAIU-3</b>) by using 4,4'-(anthracene-9,10-diyl)dibenzoic acid (H₂<b>ADBA</b>) and MnCl₂·4H₂O, which regulate the acidity of the synthetic environment. <b>XAIU-2</b> features isolated MnO₆ octahedral units, with each MnO₆ unit being bridged by two <b>ADBA</b>^2- ligands. In contrast, <b>XAIU-3</b> has MnO₆ units that are not only bridged by <b>ADBA</b>^2- ligands but also connected to adjacent MnO₆ units via the COO^- group of the <b>ADBA</b>^2- ligand. <b>XAIU-2</b> and <b>XAIU-3</b> exhibited high activity for the trifluoromethylation reaction under visible light. <b>XAIU-2</b> with oriented continuous electron transfer channels can reduce carrier recombination and extend carrier lifetime, which showed much higher activity for the trifluoromethylation reaction than that of <b>XAIU-3</b>. This study demonstrates that dimensionality modulation in MOFs serves as a potent strategy to engineer electron transport pathways and carrier dynamics, which provides a new strategy for designing high-performance photocatalysts toward selective C-H functionalization in organic synthesis.