Modulating Narrow Bandgap in a Diacetylene Functionalized Woven Covalent Organic Framework as a Visible Light Responsive Photocatalyst.

ABSTRACT

Woven covalent organic frameworks (COF) possess three dimensional frameworks with spatially isolated Cu(I) centers and have promising optoelectronic properties because of metal to ligand charge transfer (MLCT). However, despite their potential, woven COFs have not yet been investigated as photocatalysts. In this study, we developed a new woven COF, Cu-PhenBDA-COF, functionalized with diacetylene bonds. Cu-PhenBDA-COF was fully characterized, and the optoelectronic and photocatalytic properties were compared to previously reported Cu-COF-505. The diacetylene bonds of the linker positively impacted the optoelectronic properties of Cu-PhenBDA-COF and resulted in a narrower band gap and better charge separation efficiency. When the Cu(I) center was removed from both woven COFs, the absorption edge was blue shifted, resulting in a wider band gap, and there was a considerable decrease in the charge separation efficiency, underscoring the pivotal role of MLCT. This trend was reflected in the photocatalytic activity of the woven COFs toward the degradation of sulfamethoxazole in water, where the highest reaction rate constant (k app ) was recorded for the metallated diacetylene functionalized woven COF, Cu-PhenBDA-COF.