Carbon-to-nitrogen atom transmutations in a covalent organic framework transform the visible light-triggered selective oxidation of sulfides

The construction of covalent organic frameworks (COFs) for visible light-triggered chemical transformations has recently received substantial attention. In this work, four carbon-to-nitrogen atom transmutations in an established COF, TpBD-COF lead to the design of TpBmd-COF, transforming the photocatalytic performance for an arduous reaction. The integrations of 2,4,6-triformylphloroglucinol (Tp) with [1,1'-biphenyl]-4,4'-diamine (BD) and [5,5'-bipyrimidine]-2,2'-diamine (Bmd) affords TpBD-COF and TpBmd-COF, respectively. Both COFs have similar crystallinity, specific surface areas, and porous structures. However, TpBmd-COF exhibits much better separation and transfer of photogenerated charge carriers than TpBD-COF. As such, for the blue light-triggered selective oxidation of organic sulfides with oxygen (O2), TpBD-COF is inactive, while TpBmd-COF delivers significant yields of organic sulfoxides. Overall, conducting atom transmutations in a COF is a viable strategy for transforming photocatalytic performance.