Pyromellitic Diimide-Based Donor–Acceptor MOF with Panchromatic Absorption for High-Efficiency Photothermal Conversion

The incorporation of donor-acceptor components into metal-organic frameworks (MOFs) is an effective approach for developing efficient near-infrared (NIR) photothermal conversion materials; yet, their precise structural design and synthetic methodologies still present significant challenges. In this work, we present a distinctive MOF material Zn₂(bpPDI)(TTFTB)·solvent (MOF 1) constructed by the coordinated assembly of donor-acceptor components, featuring a tetrathiafulvalene tetrabenzoate (TTFTB) electron donor and a bis-pyridyl-substituted pyromellitic diimide (bpPDI) electron acceptor. The material demonstrates significant intrinsic intermolecular electron-transfer capability and possesses a long-lived TTFTB^•+ radical cation and a bpPDI^•- radical anion. These characteristics enable panchromatic absorption spanning the visible to the second near-infrared (NIR-II) region, thus allowing efficient NIR photothermal conversion. Under NIR light irradiation, MOF 1 achieves efficient photothermal conversion (ΔT_max = 137 °C under 0.5 W cm^-2 laser exposure), including rare NIR-II photothermal conversion capabilities, while exhibiting excellent thermal stability and cycling durability.