Synthesis and Reactivity of Discrete Calcium Imides

Abstract

Protonolysis of dibenzylcalcium with triphenylsilylamine affords a thf-coordinated tetrametallic calcium imide with a heterocuboid core structure. The use of calcium bis(tetramethylaluminate) as a precursor for tandem salt metathesis/protonolysis reactions with alkali metal amides of 2,6-diisopropylaniline and triphenylsilylamine provides access to Lewis acid stabilized monocalcium imides of the type [(thf)₄ Ca(μ₂ -NR)(μ₂ -Me)AlMe₂ ]. Treatment of [(thf)₄ Ca(μ₂ -NSiPh₃ )(μ₂ -Me)AlMe₂ ] with phenylsilane results in H-Si addition across the Ca-N imido bond, producing a homoleptic calcium amidoaluminate complex and putative CaH₂ whereas reaction with phenylacetylene leads to protonation of an AlMe moiety to yield the dimeric complex [(thf)Ca{NSiPh₃ }{AlMe₂ (CCPh)}]₂ .

Keywords: alkyl groups; aluminum; calcium; imides; protonolysis.