Chalcogen-bridged coordination polymer for the photocatalytic activation of aryl halides

The ability to deliver electrons is vital for dye-based photocatalysts. Conventionally, the aromatic stacking-based charge-transfer complex increases photogenerated electron accessibility but decreases the energy of excited-state dyes. To circumvent this dilemma, here we show a strategy by tuning the stacking mode of dyes. By decorating naphthalene diimide with S-bearing branches, the S & BULL;& BULL;& BULL;S contact-linked naphthalene diimide string is created in coordination polymer, thereby enhancing electron mobility while simultaneously preserving competent excited-state reducing power. This benefit, along with in situ assembly between naphthalene diimide strings and exogenous reagent/reactant, improves the accessibility of short-lived excited states during consecutive photon excitation, resulting in greater efficiency in photoinduced electron-transfer activation of inert bonds in comparison to other coordination polymers with different dye-stacking modes. This heterogeneous approach is successfully applied in the photoreduction of inert aryl halides and the successive formation of C-Ar-C/S/P/B bonds with potential pharmaceutical applications. Chalcogen-bridged naphthalene diimide coordination polymers are designed and synthesised as potent excited state reductants for the activation of inert bonds in a series of aryl halides.

Automated summary

By tuning the stacking mode of dyes, a sulfur-bridged naphthalene diimide string is created in coordination polymer, which enhances electron mobility and preserves competent excited-state reducing power. In combination with in situ assembly with exogenous reagent/reactant, this approach improves the accessibility of short-lived excited states and results in greater efficiency in photoinduced electron-transfer activation of inert bonds. This heterogeneous approach is successfully applied in the photoreduction of inert aryl halides and the formation of C-Ar-C/S/P/B bonds with potential pharmaceutical applications.