A Light-Responsive Metal–Organic Framework with Perchlorinated Nanographene Ligands

Harnessing water as a sustainable electron source for artificial photosynthesis remains a significant challenge. This work presents Alice-MOF-1, a novel zirconium metal-organic framework (MOF) incorporating hexatopic ligands with a perchlorinated hexa-peri-hexabenzocoronene (HBC) core, as a photocatalyst for CO2 reduction using water as the terminal electron donor. Contortion of the ligand, induced by edge chlorination, minimizes π-stacking and enhances solubility, enabling direct MOF synthesis. The controlled arrangement of chromophores within Alice-MOF-1 is crucial for enabling the complex multielectron redox reactions. The unique ligand architecture within the MOF promotes symmetry-breaking charge transfer (SBCT), a mechanism observed in natural photosynthesis, leading to efficient charge separation with minimal energy loss. Femtosecond transient absorption spectroscopy and time-resolved electron paramagnetic resonance spectroscopy (EPR) confirm the formation of long-lived radical ions, providing direct evidence for efficient SBCT and negligible charge recombination. These findings demonstrate the power of MOF-based chromophore assemblies to mimic nature's light-harvesting strategies for sustainable energy conversion.