Dimethylcalcium.

The salt metathesis reaction between homoleptic calcium bis(trimethylsilyl)amide [Ca{N(SiMe3 )2 }2 ]2 and "halide-free" methyllithium allowed for the isolation of X-ray-amorphous dimethylcalcium [CaMe2 ]n in good yields and purities. The formation of [CaMe2 ]n was proven by microanalysis and NMR/FTIR spectroscopic methods as well as a series of derivatization reactions. Despite slowly decomposing thf, [CaMe2 ]n could be crystallized from chilled thf solutions as the heptametallic adduct [(thf)10 Ca7 Me14 ]. Reaction of [CaMe2 ]n with CaI2 in thf led to the dimeric complex [(thf)3 Ca(Me)(I)]2 , whereas in tetrahydropyran (thp) the trinuclear complex [(thp)5 Ca3 (Me)5 (I)] was obtained, both representing the first crystallographically characterized heavy-Grignard compounds with methyl groups as the hydrocarbyl ligand. While protonolysis of [CaMe2 ]n with the superbulky proligand HTptBu,Me in nonpolar solvents gave homoleptic (TptBu,Me )2 Ca, reaction in donor solvents (thf, thp) afforded the monomeric complexes [(TptBu,Me )Ca(Me)(thf)] and [(TptBu,Me )Ca(Me)(thp)], which are the first examples bearing terminal Ca-CH3 functionalities. Grignard-type nucleophilic methyl-group transfer to hexamethylacetone gave access to the dimeric alkoxide complexes [(thf)Ca(OCtBu2 Me)2 ]2 and [(tBu2 CO)Ca(μ2 -OCtBu2 Me)3 Ca(OCtBu2 Me)]. Finally, addition of the Lewis acid GaMe3 to [CaMe2 ]n led to the corresponding tetramethylgallate compound [Ca(GaMe4 )2 ]n .