Woven covalent organic frameworks (COFs) offer immense potential as photoactive materials because Cu(I) complexes are periodically integrated into the COF structure via a single synthetic step. A photoactive interlocking (woven) COF featuring Cu(I) photosensitizers that are spatially isolated and periodically arranged in three dimensions has been successfully synthesized and characterized. The optoelectronic properties of this COF, such as light absorption and photocatalytic performance toward the degradation of sulfamethoxazole (SMX) under visible light, are investigated. The reusability and stability of this COF are compared with the Cu(PDB)₂BF₄ complex which displayed rapid deactivation and is not reusable. Conversely, The metallo-COF is stable over several catalytic cycles, highlighting a distinct advantage of the stabilizing effects of the COF over discrete molecules.

ABSTRACT:   Woven covalent organic frameworks (COF) possess entangled 3D frameworks. The metallated version of these structures contains spatially isolated Cu(I) centers and 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, a new woven COF, Cu-PhenBDA-COF, functionalized with diacetylene bonds is developed. Cu-PhenBDA-COF is fully characterized, and the optoelectronic and photocatalytic properties are compared to previously reported Cu-COF-505. The diacetylene bonds of the linker positively impact the optoelectronic properties of Cu-PhenBDA-COF and result in a narrower bandgap and better charge separation efficiency. When the Cu(I) center is removed from both woven COFs, the absorption edge is blueshifted, resulting in a wider bandgap, and there is a considerable decrease in the charge separation efficiency, underscoring the pivotal role of MLCT. This trend is reflected in the photocatalytic activity of the woven COFs toward the degradation of sulfamethoxazole in water, where the highest reaction rate constant (k_app) is recorded for the metallated diacetylene functionalized woven COF, Cu-PhenBDA-COF.

ABSTRACT:   Woven covalent organic frameworks (COF) possess entangled 3D frameworks. The metallated version of these structures contains spatially isolated Cu(I) centers and 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, a new woven COF, Cu-PhenBDA-COF, functionalized with diacetylene bonds is developed. Cu-PhenBDA-COF is fully characterized, and the optoelectronic and photocatalytic properties are compared to previously reported Cu-COF-505. The diacetylene bonds of the linker positively impact the optoelectronic properties of Cu-PhenBDA-COF and result in a narrower bandgap and better charge separation efficiency. When the Cu(I) center is removed from both woven COFs, the absorption edge is blueshifted, resulting in a wider bandgap, and there is a considerable decrease in the charge separation efficiency, underscoring the pivotal role of MLCT. This trend is reflected in the photocatalytic activity of the woven COFs toward the degradation of sulfamethoxazole in water, where the highest reaction rate constant (k_app) is recorded for the metallated diacetylene functionalized woven COF, Cu-PhenBDA-COF.