biostudies-literatureUnknown64(35)Xia XSide-on coordinated molecular hypofluorites FM(η²-OF) (M = Mg, Ca, Sr, and Ba) were prepared by co-deposition of laser-ablated alkaline earth metal atoms with diluted OF₂ in cryogenic matrices. The structures parallel the non-VESPR structures of alkaline earth metal difluorides and dihydrides, such that FMg(η²-OF) is planar, FCa(η²-OF) is planar but with a shallow bending-potential curve, while FSr(η²-OF) and FBa(η²-OF) are non-planar. Bonding analyses show that the interactions between the metal center M²⁺ and the negatively charged ligands F^- and OF^- are mainly electrostatic. Moreover, for FMg(η²-OF), donation of electron density from OF^- to empty s and p orbitals of magnesium is involved. However, for the heavier alkaline earth metal compounds, the donation to empty d orbitals of the metal center becomes dominant in orbital interactions, which contributes to their non-planar structures.Angewandte Chemie (International ed. in English)e202507151https://www.ebi.ac.uk/biostudies/studies/S-EPMC12377426biostudies-literatureSide-On Coordination in Molecular Alkaline Earth Metal Hypofluorites FM(η<sup>2</sup>-OF) (M = Mg, Ca, Sr, and Ba).PMC12377426Xia XRiedel SMedel RfalseSide-On Coordination in Molecular Alkaline Earth Metal Hypofluorites FM(η<sup>2</sup>-OF) (M = Mg, Ca, Sr, and Ba).Side-on coordinated molecular hypofluorites FM(η²-OF) (M = Mg, Ca, Sr, and Ba) were prepared by co-deposition of laser-ablated alkaline earth metal atoms with diluted OF₂ in cryogenic matrices. The structures parallel the non-VESPR structures of alkaline earth metal difluorides and dihydrides, such that FMg(η²-OF) is planar, FCa(η²-OF) is planar but with a shallow bending-potential curve, while FSr(η²-OF) and FBa(η²-OF) are non-planar. Bonding analyses show that the interactions between the metal center M²⁺ and the negatively charged ligands F^- and OF^- are mainly electrostatic. Moreover, for FMg(η²-OF), donation of electron density from OF^- to empty s and p orbitals of magnesium is involved. However, for the heavier alkaline earth metal compounds, the donation to empty d orbitals of the metal center becomes dominant in orbital interactions, which contributes to their non-planar structures.2025-01-01T00:00:00Z2025 Aug2026-05-09T19:05:55.486Z2026-04-08T01:10:46.359ZS-EPMC123774264058647610.1002/anie.202507151