A bis-aromatic MOF system constructed with a copper iodine cluster and porphyrinic ligand for enhancing near-infrared photothermal conversion†

Near-infrared (NIR) photothermal materials efficiently convert low-energy near-infrared light into heat and have a significant role across various domains. Herein, a copper iodine cluster node (Cu₁₄I₁₄) featuring inorganic aromaticity was assembled with porphyrinic ligands characterized by classical π-aromaticity to create a dual-aromatic crystalline MOF (denoted as Cu₁₄I₁₄-CuTPyP). Cu₁₄I₁₄-CuTPyP with extensive electron delocalization exhibited broad NIR absorption and achieved a high NIR photothermal conversion efficiency of 63.77% under 1064 nm laser irradiation; this efficiency surpassed those of most reported porphyrin assembly materials. By combining in situ Raman spectroscopy, transient absorption spectroscopy, and control experiments, we revealed that the cooperation between aromatic Cu₁₄I₁₄ and porphyrin led to an active electron transfer pathway in Cu₁₄I₁₄-CuTPyP, which consumed a considerable amount of excited-state molecules (71.4%) through ultrafast nonradiative relaxation channels (2.1 ps). In this study, our thorough investigation of the photothermal properties of bis-aromatic MOFs could aid in setting a new standard for material design.