A Stable Crown Ether Complex with a Noble‐Gas Compound

Abstract

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.

Xenon Trioxide Adducts of O‐Donor Ligands; [(CH3)2CO]3XeO3, [(CH3)2SO]3(XeO3)2, (C5H5NO)3(XeO3)2, and [(C6H5)3PO]2XeO3

“…As previously shown for (CH 2 CH 2 O) 5 XeO 3 , the calculated Xe−O and Xe‐ ‐ ‐O distances are in better agreement with the experimental values when calculated by the APFD method than by the B3LYP method, which overestimates these bond lengths (APFD: Xe−O: 1 1.768–1.768 Å, 2 1.760–1.780 Å, 3 1.763–1.772 Å, 4 1.764–1.769 Å; Xe‐ ‐ ‐O: 1 2.750–2.753 Å, 2 2.675–2.825 Å, 3 2.616–2.680 Å, 4 2.607, 2.654 Å. B3LYP: Xe−O: 1 1.784–1.786 Å, 2 1.784–1.788 Å, 3 1.781–1.792 Å, 4 1.783–1.786 Å; Xe‐ ‐ ‐O: 1 2.864–2.866 Å, 2 2.859–2.883 Å, 3 2.639–2.830 Å, 4 2.722, 2.730 Å).…”

“…Solid XeO 3 detonates on contact with liquid dimethylsulfoxide (DMSO) and acetylacetone but readily dissolves in acetone without incident. The solutions have proven to be stable for up to several months at room temperature and have been used in other synthetic applications . When acetone solutions of XeO 3 were slowly evaporated at room temperature, solid γ‐XeO 3 was recovered, but slow cooling of these solutions from 20 to −78 °C resulted in the growth of clear, colorless, block‐shaped crystals of [(CH 3 ) 2 CO] 3 XeO 3 ( 1 ) [Eq. ]…”

Xenon Trioxide Adducts of O-Donor Ligands; [(CH3)2CO]3XeO3, [(CH3)2SO]3(XeO3)2, (C5H5NO)3(XeO3)2, and [(C6H5)3PO]2XeO3

“…[5−7] The xenon-ligand bonds of XeO3 adducts are best described as predominantly electrostatic, (weakly covalent) interactions between the highly electrophilic σholes of the Xe atom and the nucleophilic region of the electronegative ligand atom. [5,7,8] Secondary bonding interactions occur approximately trans to the three primary Xe-O bonds, as observed for the N-coordinated pyridine and pyridinium salt adducts [7] and nitrile adducts [8] of XeO3. In the case of (CH2CH2O)5XeO3, the σ-bonding interactions that occur between the electrophilic xenon atom and the five nucleophilic oxygen atoms of the crown ether ligand result in a xenon coordination number of 8, the highest coordination number observed thus far for Xe VI in an XeO3 adduct.…”

Theoretical investigation on the structure and stability of some neutral noble gas compounds containing Xe‐Xe bond

“…Although just limited noble gas molecules have been synthesized experimentally, many types of noble gas compounds are possible from theoretical point of view . This list includes compounds which have been also observed experimentally; such as XeF 6 , KrF 2 , HArF, clathrates and clathrate hydrates, coordination compounds, hydrates (Xe.6H 2 O), HeH + , oxyfluorides (XeOF 2 , XeOF 4 , Xe 2 O 3 F 2 , XeO 2 F 4 ), and fullerene compounds.…”