Organoethynylxenon(II) Tetrafluoroborates, [RC≡CXe][BF4] – The First Examples of Isolated Alkynylxenonium Salts: Preparation and Multi-NMR Characterisation

Substitution of fluorine in M[C6F5BF3] with organolithium compounds: distinctions between O- and N-nucleophiles

Borates M[C₆F₅BF₃] (M = K, Li, Bu₄N) react with organolithium compounds, RLi (R = Me, Bu, Ph), in 1,2-dimethoxyethane or diglyme to give M[4-RC₆F₄BF₃] and M[2-RC₆F₄BF₃]. When R is Me or Bu, the nucleophilic substitution of the fluorine atom at the para position to boron is the predominant route. When R = Ph, the ratio M[4-RC₆F₄BF₃]/M[2-RC₆F₄BF₃] is ca. 1:1. Substitution of the fluorine atom at the ortho position to boron is solely caused by the coordination of RLi via the lithium atom with the fluorine atoms of the BF₃ group. This differs from the previously reported substitution in K[C₆F₅BF₃] by O- and N-nucleophiles that did not produce K[2-NuC₆F₄BF₃].

Metastable behavior of noble gas inserted tin and lead fluorides

The metastable FNgEF and FNgEF₃ (E = Sn, Pb; Ng = Kr–Rn) are the first reported neutral compounds possessing Ng–Sn and Ng–Pb covalent bonds.

Atypical compounds of gases, which have been called ‘noble’

In this critical review I describe fascinating experimental and theoretical advances in 'noble gas' chemistry during the last twenty years, and have taken a somewhat unexpected course since 2000. I also highlight perspectives for further development in this field, including the prospective synthesis of compounds containing as yet unknown Xe-element and element-Xe-element bridging bonds, peroxide species containing Xe, adducts of XeF(2) with various metal fluorides, Xe-element alloys, and novel pressure-stabilized covalently bound and host-guest compounds of Xe. A substantial part of the essay is devoted to the-as yet experimentally unexplored-behaviour of the compounds of Xe under high pressure. The blend of science, history, and theoretical predictions, will be valued by inorganic and organic chemists, materials scientists, and the community of theoretical and experimental high-pressure physicists and chemists (151 references).