Hydridostannylene Derivatives of Magnesium and Calcium.

Reactions of a m-terphenylhydridostannylene with β-diketiminato magnesium and calcium hydrides provide bis-μ-hydrido species, the heterobimetallic constitutions of which are maintained after the addition of THF donor solvent. In both cases, reactions with hex-1-ene result in the formation of tetravalent organostannyl alkaline earth derivatives. Whereas the magnesium reagent undergoes facile twofold addition, the calcium-centered process is arrested after a single alkene reduction event.

Nucleophilic Triphenylgermanides of Magnesium and Calcium.

The dimeric calcium and magnesium hydrides, [(BDI)AeH] [BDI=HC{(Me)CNDipp}, Dipp=2,6-i-PrCH; Ae=Mg or Ca] do not react with PhGeH in non-coordinating solvent. Addition of THF, however, induces deprotonation and access to monomeric Ae-germanide complexes, [(BDI)Ae{GePh}(THF)], both of which have been structurally characterized. Although this process is facile when Ae=Ca, the analogous magnesium-based reaction requires heating to temperatures >100 °C, under which conditions germanide formation is complicated by THF ring opening and the generation of an alkaline earth germyl-C-terminated n-butoxide, [(BDI)Mg{μ-O(CH)GePh}].

A series of neutral alkaline earth metal hydride complexes supported by a bulky, unsymmetrical β-diketiminate ligand, [{(Nacnac)M(μ-H)}] (M = Mg, Ca, Sr or Ba).

A bulky, unsymmetrical β-diketiminate ligand, [HC{MeCN(Dip)}{MeCN(TCHP)}] (Nacnac; Dip = 2,6-diisopropylphenyl, TCHP = 2,4,6-tricyclohexylphenyl), has been utilised in the preparation of a series of magnesium alkyl and calcium, strontium and barium amide complexes. Reaction of these with PhSiH afforded the first complete series of β-diketiminato heavier group 2 metal hydride complexes, [{(Nacnac)M(μ-H)}] (M = Mg, Ca, Sr or Ba). The unsymmetrical nature of the β-diketiminate ligand seemingly promotes stabilising interactions of ligand Dip groups with the metal centres in the Ca, Sr and Ba hydride complexes.