A Comparative Study of (Poly)ether Adducts of Alkaline Earth Iodides – An Overview Including New Compounds

Abstract

AbstractNew homoligand and mixed‐ligand adducts of the heavier alkaline earth metal (Ca, Sr, Ba) halides with oxygen‐donor polyether ligands have been isolated and characterized and are compared with previously obtained compounds of the same class in order to give an overview on structures and properties. Homoligand halide adducts, discussed herein, are [CaI(DME)3]I (1), trans‐[SrI2(DME)3] (2), trans‐[BaI2(DME)3] (3), (DME = ethylene glycol dimethyl ether), [CaI(diglyme)2]I (4), cis‐[SrI2(diglyme)2] (5), trans‐[BaI2(diglyme)2] (6),(diglyme = diethylene glycol dimethyl ether, [SrI(triglyme)2]I (7), and [BaI(triglyme)2]I (8), (triglyme = triethylene glycol dimethyl ether). Introduction of the mono‐coordinating THF ligand (THF = tetrahydrofuran) in the coordination sphere of 1, 2, 3, 4 allows the formation of the new mixed‐ligand compounds trans‐[CaI2(DME)2(THF)] (9), trans‐[SrI2(DME)2(THF)] (10), trans‐[BaI2(DME)2(THF)2] (11), and trans‐[CaI2(diglyme)2(THF)2] (12). These compounds were obtained from the metal halide salts in solution with pure or mixtures of ether solvents. While compounds 1–8 appear to be very stable and non‐reactive, adducts 9–12 present a comparable reactivity to the well known THF adducts [MI2(thf)n] (M = Ca, n = 4; Sr, Ba, n = 5).