Facile One-Step Synthesis of MPHMes from MesPCl₂ (M = Li, Na, K; Mes = 2,4,6-Me₃C₆H₂)

Reaction of alkali metals (Li, Na, K) with mesityldichloro­phosphane (MesPCl₂, Mes = 2,4,6-Me₃C₆H₂) in ethereal solvents leads to formation of the corresponding mesitylphosphanides MPHMes in good purity and yield. ³¹P NMR spectroscopic studies in deuterated solvents strongly support a mechanism of the reaction that involves protonation/disproportionation steps in which the solvent is the only possible proton source. Li­(thf)­(tmeda)­PHMes (1), [Na­(tmeda)­(μ-PHMes)]_∞ (2), and [K­(pmdeta)­(μ-PHMes)]₂ (3) (tmeda = N,N,N′,N′-tetramethylethylenediamine, pmdeta = N,N,N′,N″,N″-pentamethyldiethylenetriamine) were obtained; in the solid state, 2 forms zigzag chains while 3 is a dimeric compound.