Dilithium and Magnesium Alkanediides and 1‐Oxaalkanediides

Abstract

Abstract. Dilithium and magnesium alkanediides of the types Li(CH 2 ) n Li and [Mg(CH 2 ) n ] x represent substance classes with a long tradition, however, the interest in these compounds ceased in recent years. Numerous reasons account for the vanishing attention such as challenging synthetic procedures, poor to moderate yields, complex structures in solution and the solid state, and complex equilibria in solution. Degradation processes (ether degradation, β-hydride elimination, indirect reduction reactions) increase the intricacy of these compounds because these degradation products take part in the solution equilibria. -(X = H, Cl) with an X-centered Li 12 icosahedron. Despite these challenges, the dilithium and magnesium alkanediides are a fascinating substance class with a rich chemistry by its own (such as Schlenk-type equilibria) and as metalating and reducing reagents. The enormous sensitivity toward moisture (hydrolysis reactions) and air (oxidation processes) and reactivity toward ethereal media (ether degradation reac-

Structure–Solubility Relationship of 1,4‐Dioxane Complexes of Di(hydrocarbyl)magnesium

“…Crystallization of 2'-Br from a solvent mixture of DMF and dioxane led to the precipitation of [{(dmf) 6 Mg}Br 2 ] (A). Crystallization of 2'-Br from a solvent mixture of DMF and dioxane led to the precipitation of [{(dmf) 6 Mg}Br 2 ] (A).…”

“…Traces of water 6 and 252.1 pm). With very few exceptions, in which the Schlenk equilibrium lies completely on the side of heteroleptic RMgX complexes (such as [(Me 3 Si) 2 C{MgBr(dx) 2 } 2 ]), [6] the dioxane method provides advantageous access to soluble R 2 M compounds. Extraction of [MgBr 2 (dx) 2 ] 1 (2'-Br) with hot 1,2-dimethoxyethane (dme) only allowed the isolation of the already known [cis-Br 2 Mg(dme) 2 ] (C).…”

“…[6] Ten years ago, the influence of dioxane on the Schlenk equilibrium was studied more explicitly. It proves to be very beneficial to allow the MgX 2containing precipitate to age overnight at room temperature.…”

Chasing Multiple Bonding Interactions between Alkaline‐Earth Metals and Main‐Group Fragments

“…Indeed there are reports, fore xample, on lithium methylidene (also termed lithium methylene) [Li 2 CH 2 ] n ,but the preparation of this highly reactive compound is not straightforward and the amorphous/polymeric nature causes solubility issues which further complicate its use in metathesis reactions. [71][72][73][74][75] The availability of Grignard and dialkylmagnesium compounds led to early attempts to synthesize Mg II -alkylidenes pecies and first reports on heteroleptic Mg methylidene species [CH 2 (MgBr) 2 ]a ppeared in 1926. [76] However,t his di-Grignard compound, which can be preparedu sing dibromomethane CH 2 Br 2 and Mg 0 or Mg amalgam (route c), attracted only sporadic attention.…”

Syntheses and Molecular Structures of [(thf)4Li] [{(thf)Li}M(C4H8)3] (M = Zr, Hf) and Their Solution Behavior

“…The bifunctional synthon 1,4‐dilithiobutane enables the syntheses of metallacycles and metalates with the butane‐1,4‐diide acting as a chelate base. Crystallographically authenticated homoleptic metalates have been reported for chromium(II), nickel(II), platinum(II), magnesium(II), and zinc(II) . In order to study the dependency of the molecular structures on the oxidation state of the metal we also prepared and investigated the yttrium(III) congener .…”