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

Abstract

Dedicated to Prof. Sjoerd Harder on the occasion of his 60 th birthday.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(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 Schlenktype equilibria, interconverting these compounds into their homoleptic counterparts.

Low-Coordinate Magnesium Sulfide and Selenide Complexes

“…The Mg–O bond distance to the anionic diphenyl­phosphinite is only slightly shorter than that to the neutral triphenyl­phosphinoxide (Mg1–O2 1.9000(16) versus Mg1–O1 1.9243(14)), and the P–O bond in the P V ligand (P1–O1 1.4972(13)) is, as expected, shorter than that in the phosphinite (P2–O2 1.5459(17)). These features compare well to those of other alkaline earth metal complexes with diphenylphosphinite ligands. − …”

“…These features compare well to those of other alkaline earth metal complexes with diphenylphosphinite ligands. 43 − 48 …”