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 micro-analysis 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)Ca7Me14]. 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)Ca-3(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 HTp(tBu,Me) in nonpolar solvents gave homoleptic (Tp(tBu,Me))(2)Ca, reaction in donor solvents (thf, thp) afforded the monomeric complexes [(Tp(tBu,Me))Ca(Me)(thf)] and [(Tp(tBu,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(OCtBu(2)Me)(2)](2) and [(tBu(2)CO)Ca(mu 2-OCtBu(2)Me)(3)-Ca(OCtBu(2)Me)]. Finally, addition of the Lewis acid GaMe3 to [CaMe2](n) led to the corresponding tetramethylgallate compound [Ca(GaMe4)(2)](n).