Zirconium Photocatalysis for Inert Bond Activation: Direct C(sp3)−H Functionalization, Decarboxylative Amination, and Polystyrene Oxidative Degradation

Zirconium (Zr) is an earth-abundant, environmentally benign, and biocompatible element, yet its role in organic synthesis has historically been limited to transformations of active substrates like alkenes and alkynes. In contrast, the direct catalytic functionalization of inert yet abundant feedstocks, including alkanes, free aliphatic acids, and nonpolar polymers such as polystyrene (PS), remains a formidable challenge. Herein, we report that commercially available ZrCl 4 exhibits potent ligand-to-metal charge transfer (LMCT) reactivity under light irradiation, establishing a unified photocatalytic platform for the activation of the highly thermodynamically stable C(sp 3 )−H and C−C bonds and functionalization of these inert materials. Operating under simple “dump-and-stir” conditions at ambient temperature, the method employs low catalyst loadings to convert alkanes and aliphatic acids directly into high-value C−N, C−C, and C−S coupled products. Remarkably, the same system facilitates near-complete oxidative depolymerization of PS, predominantly yielding benzoic acid, which is a fundamental industrial building block. These findings unveil a previously unknown dimension of zirconium photochemistry, significantly expanding the synthetic versatility of this overlooked metal. Moreover, the strategy offers a general blueprint for sustainable catalysis, enabling efficient bond formation and the productive upgrading of inert feedstocks for both academic and industrial applications.