Photoresponsive Metal–Organic Frameworks via Benzotrithiophene-Based Unique Double-Linker Walls

Photoresponsive metal–organic frameworks (MOFs) are key materials for optical devices and photocatalysts. Linker structures that induce strong π–π interactions are ideal to produce such MOFs. We designed and synthesized a new linker, benzophenyltrithiophenecarboxylate (BPTTC), to induce π–π interactions by leveraging its conjugated and planar structure. Our synthetic efforts yield single crystals of Zn-BPTTC, which exhibited a rare double-linker structure, supported by synchrotron single-crystal X-ray crystallography. We then successfully synthesized an isostructural Cu-BPTTC, which supports the double-linker structure. Both MOFs exhibit photoluminescence and photocurrent density around 250 μA cm–2. Computational studies corroborate the influence of π–π interactions in double-linker wall formation and electronic structure differences from single-linker MOFs. This work highlights the importance of conjugated planar linker designs that leverage the proximity of linkers in the MOF structure to achieve photoresponsiveness. We envision that future conjugated linker designs for double-linker-based MOFs can further fine-tune their photophysical properties.