Synthesis and reactivity of an anionic NHC-borane featuring a weakly coordinating silicate anion

We report herein the synthesis of a new NHC-stabilised borane complex featuring weakly coordinating anion, namely pentaorganosilicate, on NHC backbone. The can be achieved from zwitterionic abnormal silicate-imidazolium adduct by deprotonation with strong base followed quenching transfer agent. Alternatively, IPr-BH3 also deprotonated and resulting vinylanion is trapped tetravalent spirosilane. first structural data lithium derivative an anionic NHC-borane functionalized silicate have been obtained reveal interaction between three hydrogens cation. Assessment reactivity highlights higher hydridicity compared to parent IPr-BH3. Finally, electronic properties this species evaluated means DFT calculations presence backbone raises HOMO which in part explain high hydride-donor abilities. This consistent smooth reduction aldehyde without Lewis acid additive.