Amidomagnesium cations

Abstract

We report the synthesis, structure and reactivity of molecular amidomagnesium cations bearing tris{2-(dimethylamino)-ethyl}amine (Me₆TREN). Me₆TREN binds to the cationic magnesium centre exhibiting κ⁴ and κ³ coordination modes in [Me₆TREN-Mg-N(SiHMe₂)₂]⁺ and [Me₆TREN-Mg-N(SiMe₃)₂]⁺ respectively. [Me₆TREN-Mg-N(SiHMe₂)₂]⁺ reacts with benzophenone resulting in the insertion of the carbonyl group across β-SiH bond. The reaction between [Me₆TREN-Mg-N(SiMe₃)₂]⁺ and CO₂ leads to [Me₆TREN-Mg-OSiMe₃]⁺, while the reaction with H₂O results in [Me₆TREN-Mg-OH]₂²⁺. Attempts to prepare hydridomagnesium cations from [Me₆TREN-Mg-N(SiMe₃)₂]⁺ using KH resulted in the precipitation of MgH₂ and the isolation of [(Me₆TREN)K(THF)₃]⁺.