Neopentyl beryllium compounds, and complexes of methyl(-neopentyl)beryllium

Abstract

The neopentylberyllium complexes (Me₃C·CH₂)₂Be(OEt₂), (Me₃C·CH₂)₂Be(NMe₃), and (Me₃C·CH₂)₂Be(tmed)(tmed = tetramethylethylenediamine) are described. Both ethyl- and neopentyl-beryllium bromide yield crystal-line monomeric tmed complexes, but reaction between neopentylberyllium bromide and trimethylamine results in disproportionation to (Me₃C·CH₂)₂Be(NMe₃). Neopentylberyllium hydride forms a soluble monomeric tmed complex, (Me₃C·CH₂BeH)₂(tmed).

The equilibrium between dimethylberyllium–trimethylamine and dineopentylberyllium–trimethylamine in cyclopentane at –40° favours the mixed methyl(neopentyl)beryllium complex. The methyl(neopentyl)beryllium–tmed complex has been isolated.