Cyclopalladation of a covalent organic framework for near-infrared-light-driven photocatalytic hydrogen peroxide production
Andrés Rodríguez‐Camargo, Maxwell W. Terban, Martina Paetsch, Elio Rico, Daniel Gräf, Radhika Hirpara, Viola Düppel, Igor Moudrakovski, Martin Etter, Néstor Guijarro, Christian Ochsenfeld, Robert E. Dinnebier, Liang Yao, Bettina V. Lotsch
Abstract
Abstract Covalent organic frameworks (COFs) have been developed as photosensitizers for photocatalytic energy conversion over the past decade; however, COF photocatalysts have yet to demonstrate the ability to harvest near-infrared light (above 760 nm, approximately 53% of the solar spectrum) for fuel or chemical conversion. In this work we introduce a post-synthetic functionalization strategy for COFs by incorporating a palladacycle directly into the COF backbone, extending the light absorption of an azobenzene-based COF into the near-infrared region. This approach enables homogeneous, atomically distributed palladium functionalization with a high loading of 12 wt% and without noticeable formation of palladium nanoparticles. The cyclopalladated COF, TpAzo-CPd, was used as a catalyst for photocatalytic hydrogen peroxide production under 810 nm illumination. This study demonstrates the use of COFs for near-infrared photocatalysis and opens the door to palladium-single-site COF catalysts for a wide range of chemical transformations.