Brønsted and Lewis Base Behavior of Sodium Amidotrihydridoborate (NaNH2BH3)

The reactivity of sodium amidoborane (NaNH2BH3) as a Brønsted and Lewis base was studied systematically. The [NH2BH3]– anion can act as a proton acceptor or a hydride donor in different types of reactions. In reactions with very weak Brønsted acids such as cyclopentadiene, ammonia, and pyrazole, the [NH2BH3]– anion acts as a proton acceptor through the lone pair on N. The reactions of [NH2BH3]– with stronger Brønsted acids are complicated. In the reaction with ammonium chloride or acetic acid, [NH2BH3]– accepts a proton, reforming NH3BH3. However, in the reaction with HCl or methanol, N–B bond cleavage occurs. [NH2BH3]– can also donate hydride in some reactions. The possible mechanisms of these reactions are discussed. The reactivity of sodium amidoborane (NaNH2BH3) was studied systematically. The [NH2BH3]– anion can act as a proton acceptor through the lone pair on N in reactions with weak Brønsted acids such as cyclopentadiene, ammonia, and pyrazole, but reactions with stronger Brønsted acids are complicated. It can also donate hydride in some reactions. Possible mechanisms of these reactions are discussed.