A Stable Crown Ether Complex with a Noble‐Gas Compound

Crown ethers have been known for over 50 years, but no example of a complex between a noble-gas compound and a crown ether or another polydentate ligand had previously been reported. Xenon trioxide is shown to react with 15-crown-5 to form the kinetically stable (CH₂ CH₂ O)₅ XeO₃ adduct, which, in marked contrast with solid XeO₃ , does not detonate when mechanically shocked. The crystal structure shows that the five oxygen atoms of the crown ether are coordinated to the xenon atom of XeO₃ . The gas-phase Wiberg bond valences and indices and the empirical bond valences indicate that the Xe- - -O_crown bonds are predominantly electrostatic and are consistent with σ-hole bonding. Mappings of the electrostatic potential (EP) onto the Hirshfeld surfaces of XeO₃ and 15-crown-5 in (CH₂ CH₂ O)₅ XeO₃ and a detailed examination of the molecular electrostatic potential surface (MEPS) of XeO₃ and (CH₂ CH₂ O)₅ reveal regions of negative EP on the oxygen atoms of (CH₂ CH₂ O)₅ and regions of high positive EP on the xenon atom, which are also in accordance with σ-hole interactions.