170234 20260407115449.0 doi 10.1038/s41467-026-69257-8 sideral 148717 ART-2026-148717 eng Tarifa, Luis Cooperative anion activation at a cobalt center through ion pairing and ligand design 2026 Weakly coordinating anions (WCAs) are commonly used to stabilize highvalent, electrophilic transition-metal complexes, owing to their low nucleophilicity and minimal coordinating ability. Here, we present a cobalt platform supported by a tris(2-pyridyl)(N-picolyl)imidazolidine ligand (Py4Im) that generates a directional, protic cavity for ion pairing. This environment enables a comparative study of BF4 – and PF6⁻, showing that PF6⁻ undergoes fluoride abstraction under mild conditions, while BF4 – remains unreactive unless assisted by a Lewis base. The PF6⁻ activation yields a well-defined CoIII–F complex that acts as an efficient nucleophilic fluoride source. DFT calculations and diffusion NMR experiments highlight the critical role of anion-cation pairing in modulating reactivity, overriding intrinsic thermodynamic preferences. These findings showcase supramolecular control of WCA activation by a late transition metal and provide new design principles for reactivity modulation via counterion selection. Access copy available to the general public Unrestricted info:eu-repo/grantAgreement/ES/AEI/PID2020-119512GB-I00 info:eu-repo/grantAgreement/ES/AEI/PID2023-148472NB-I00 info:eu-repo/grantAgreement/ES/DGA/E50-23R info:eu-repo/grantAgreement/ES/MCIN/RYC2021- 033807-I info:eu-repo/grantAgreement/ES/MICINN/RED2022-134074-T info:eu-repo/semantics/openAccess by-nc-nd https://creativecommons.org/licenses/by-nc-nd/4.0/deed.es info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Cano-Asensio, Judit López, José A. (orcid)0000-0003-4500-1974 Tejel, Cristina (orcid)0000-0003-3306-0635 Geer, Ana M. (orcid)0000-0003-1115-6759 17, 1 (2026), 2469 [11 pp.] Nature communications 2041-1723 2170615 http://zaguan.unizar.es/record/170234/files/texto_completo.pdf Versión publicada 2795828 http://zaguan.unizar.es/record/170234/files/texto_completo.jpg?subformat=icon icon Versión publicada oai:zaguan.unizar.es:170234 articulos driver 2026-03-26-14:32:15 ARTICLE