Exploiting Deprotonative Co‐complexation to Access Potassium Metal(ates) Supported by a Bulky Silyl(bis)amide Ligand

Bimetallic complexes combining an alkali‐metal with a lower electropositive metal have demonstrated unique chemical profiles which can be rationalised in terms of chemical cooperativity. Advancing the rational design of these types of complexes, a adaptable method is described to prepare a new family of potassium metal(ates) containing the highly sterically demanding silyl(bis)amide {Ph 2 Si(NAr*) 2 } 2− (Ar*=2,6‐diisopropylphenyl). Using a sequential deprotonative co‐complexation approach, mono‐metallation of Ph 2 Si(NHAr*) 2 ( 1 ) is accomplished using potassium alkyl KCH 2 SiMe 3 yielding [{Ph 2 Si(NHAr*)(NAr*)K} ∞ ] ( 2 ), which, in turn, undergoes co‐complexation with the relevant M(CH 2 SiMe 3 ) 2 (M=Mg, Zn, Mn) enabling metallation of the remaining NHAr* group to furnish silylbis(amido) alkyl potassium metal(ates) [{Ph 2 Si(NAr*) 2 M(THF) x (CH 2 SiMe 3 )} − {K(THF) y } + ] (M=Zn, x=0, y=4, 3 ; M=Mg, x=1, y=3, 4 ; and M=Mn, x=0, y=4, 5 ). Reactivity studies of potassium manganate 5 with the amine HMDS(H) (HMDS=N[SiMe 3 ] 2 revealed the kinetic activation of the remaining alkyl group on Mn furnishing [K(THF) 2 {Ph 2 Si(NAr*) 2 }Mn(HMDS)] ( 6 ). The structures of these bimetallic complexes along with that of the potassium precursor 2 have been established by X‐ray crystallographic studies.