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 (CH CH O) XeO adduct, which, in marked contrast with solid XeO , 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 XeO . The gas-phase Wiberg bond valences and indices and the empirical bond valences indicate that the Xe- - -O bonds are predominantly electrostatic and are consistent with σ-hole bonding. Mappings of the electrostatic potential (EP) onto the Hirshfeld surfaces of XeO and 15-crown-5 in (CH CH O) XeO and a detailed examination of the molecular electrostatic potential surface (MEPS) of XeO and (CH CH O) reveal regions of negative EP on the oxygen atoms of (CH CH O) and regions of high positive EP on the xenon atom, which are also in accordance with σ-hole interactions.