Kallmeier, FabianNelmes, Gareth R.McMullin, Claire L.Edwards, Alison J.Hicks, Jamie2026-02-262026-02-262041-6520ORCID:/0000-0001-7073-2766/work/206440497ORCID:/0000-0001-9450-2594/work/206444461https://hdl.handle.net/1885/733806672Anionic aluminium(i) complexes, or aluminyl anions, are a recently discovered class of main group compounds that can C-H activate simple aromatic molecules. However, functional group tolerance remains an issue, with the activation of functionalised arenes often favouring more kinetically accessible side reactions (e.g. C-O/C-F activation) over the desired C-H activation. Here, we report a new, electron-rich potassium aluminyl complex, which by DFT has been calculated to be the most nucleophilic diamido aluminyl anion reported to date. The anion shows unprecedented rates of reaction towards the C-H activation of arenes, achieving the C-H activation of stoichiometric benzene in seconds at room temperature. Furthermore, the C-H activation is selective even in a range of functionalised arenes, including those with C-O and C-F bonds.JH would like to thank the Australian Research Council (FT240100229) for the funding of this work. We acknowledge the support of the Australian Centre for Neutron Scattering, ANSTO and the Australian Government through the National Collaborative Research Infrastructure Strategy supporting the neutron research infrastructure in this work via ACNS proposal 18886. This research was undertaken with the assistance of resources from the National Computational Infrastructure (NCI Australia), an NCRIS enabled capability supported by the Australian Government, and the University of Bath's Research Computing Group (https://doi.org/10.15125/b6cd-s854) for their support in this work.9en©2025 The authors2025-05-1310.1039/d5sc02682b105005762330