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

Abstract Alkaline‐earth metalation of dimesitylphosphane oxide Mes 2 P(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‐OPMes 2 )] 2 (L/R=thf/Et ( 2‐Et ), Et 2 O/Br ( 2‐Br )), [(thf) 3 Ca(hmds)(OPMes 2 )] ( 3‐hmds ), [(thf) 3 Mg(OPMes 2 ) 2 ] ( 2‐thf ) and [(thf) 4 Ae(OPMes 2 ) 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(OPMes 2 ) 2 ] ( 3‐dme ), [(thf) 2 (diglyme)Ca(OPMes 2 ) 2 ] ( 3‐diglyme ) and [(thf)(triglyme)Ca(OPMes 2 ) 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.