Triple hydrogen atom abstraction from Mn–NH3 complexes results in cyclophosphazenium cations

Abstract

All hydrogen atoms of the NH₃ in [Mn(depe)₂(CO)(NH₃)]⁺ are abstracted by 2,4,6-tri-tert-butylphenoxyl radical, resulting in the isolation of a rare cyclophosphazenium cation, [(Et₂P(CH₂)₂PEt₂)N]⁺, in 76% yield. An analogous reaction is observed for [Mn(dppe)₂(CO)(NH₃)]⁺. Computations suggest insertion of NH_x into a Mn–P bond provides the thermodynamic driving force. Contextualization of this reaction provides insights on catalyst design and breaking strong N–H bonds.