Alkaline‐earth metal dimesitylphosphinites and their ether adducts – A structural study in solution and in the crystalline state

Abstract

AbstractAlkaline‐earth metalation of dimesitylphosphane oxide Mes2P(O)H (1) in ethereal solvents with dialkylmagnesium and alkylmagnesium bromide as well as the homoleptic bis(trimethylsilyl)amides of calcium, strontium, and barium yields [(L)MgR(μ‐OPMes2)]2 (L/R=thf/Et (2‐Et), Et2O/Br (2‐Br)), [(thf)3Ca(hmds)(OPMes2)] (3‐hmds), [(thf)3Mg(OPMes2)2] (2‐thf) and [(thf)4Ae(OPMes2)2] (Ae=Ca (3‐thf), Sr (4‐thf), and Ba (5‐thf)), depending on the applied stoichiometry. Exchange of thf ligands in 3‐thf by oligodentate ethers allows isolation of [(thf)2(dme)Ca(OPMes2)2] (3‐dme), [(thf)2(diglyme)Ca(OPMes2)2] (3‐diglyme) and [(thf)(triglyme)Ca(OPMes2)2] (3‐triglyme). Contrary to this finding, oligodentate amines are unable to substitute ligated thf ligands in 3‐thf. In ethereal solutions, the heteroleptic complexes 2‐Et, 2‐Br and 3‐hmds show Schlenk‐type equilibria, interconverting these compounds into their homoleptic counterparts.