Nature – Purdy et al. (2025): Reversible fluorenol photobases that perform CO₂ capture and concentration from ambient air
Michael Purdy, Ariel Y. Wang, Matthew C. Drummer, Daniel G. Nocera and Richard Y. Liu, IN: Nature Chemistry, https://doi.org/10.1038/s41557-025-01901-0
Leading strategies for the capture of CO₂ from point sources and directly from the atmosphere face high energy costs for thermal sorbent regeneration. Photochemical processes, driven by sunlight as the sole external stimulus, offer a promising alternative. Despite many reported examples of light-induced pH swings using metastable photoacids, the complementary mode of operation, using photoswitchable bases, has not been extensively considered. This is due in part to the rarity of photobases that can support large, reversible pH jumps in water. Here the authors report the design of fluorenol-based Arrhenius photobases that take advantage of excited-state aromaticity and ground-state antiaromaticity to generate large basicity swings with high reversibility.