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Abstract Organic fluoronium ions can be described as positively charged molecules in which the most electronegative and least polarizable element fluorine engages in two partially covalent bonding interactions to two carbon centers. While recent solvolysis experiments and NMR spectroscopic studies on a metastable [C–F–C]⁺fluoronium ion strongly support the divalent fluoronium structure over the alternative rapidly equilibrating classical carbocation, the model system has, to date, eluded crystallographic analysis to confirm this phenomenon in the solid state. Herein, we report the single crystal structure of a symmetrical [C–F–C]⁺fluoronium cation. Besides its synthesis and crystallographic characterization as the [Sb₂F₁₁]⁻salt, vibrational spectra are discussed and a detailed analysis concerning the nature of the bonding situation in this fluoronium ion and its heavier halonium homologues is performed, which provides detailed insights on this molecular structure. 

Abstract We report a detailed experimental and theoretical analysis of through‐space arene activation with halogens, tetrazoles and achiral esters and amides. Contrary to previously assumed direct activation through σ‐complex stabilization, our results suggest that these reactions proceed by arelaymechanism wherein the lone pair‐containing activators form exothermic π‐complexes with electrophilic nitronium ion before transferring it to the probe ring through low barrier transition states. Noncovalent interactions (NCI) plots and Quantum Theory of Atoms in Molecules (QTAIM) analyses depict favorable interactions between the Lewis base (LB) and the nitronium ion in the precomplexes and the transition states, suggesting directing group participation throughout the mechanism. The regioselectivity of substitution also comports with a relay mechanism. In all, these data pave the way for an alternate platform of electrophilic aromatic substitution (EAS) reactions. 

Abstract The putative interaction of a C−F bond with an amide carbonyl has been an intriguing topic of interest in this century for reasons spanning basic physical organic chemistry to biochemistry. However, to date, there exist no examples of a close, well‐defined interaction in which its unique aspects can be identified and exploited. Herein, we finally present an engineered system possessing an exceptionally tight C−F‐amide interaction, allowing us to obtain spectroscopic, crystallographic, and kinetic details of a distinctive, biochemically relevant chemical system for the first time. In turn, we also explore Lewis acid coordination, C−F bond promotion of amide isomerization, enantiomerization, and ion protonation processes.