[E(μ-NBbp)]2 (E = P, As) – group 15 biradicals synthesized from acyclic precursors

Abstract

The synthesis of Bbp stabilized biradicals of the type [E(μ-NBbp)]₂ (E = P, As) (Bbp = 2,6-bis[bis(trimethylsilyl)methyl]phenyl) was investigated. Contrary to the established synthetic protocol for terphenyl substituted biradicals [E(μ-NTer)]₂ by reduction of [ClE(μ-NTer)]₂, the analogous Bbp substituted precursor [ClE(μ-NBbp)]₂ could only be obtained in low yields. For this reason, a new synthesis had to be found to generate [E(μ-NBbp)]₂. Instead of using cyclic [ClE(μ-NBbp)]₂ we prepared the acyclic Bbp–N(ECl₂)₂ species starting from Bbp–NH₂ and ECl₃ and studied the reduction with magnesium chips, which led to the formation of the desired biradicals [E(μ-NBbp)]₂. All species along the reaction path were fully characterized.