Cyclo-Pnicta-triazanes: Biradicaloids or Zwitterions?

摘要

Bulky triazenides were utilized in the reaction with pnictogen(Ⅲ) chlorides (ECl_3, E = P, As, Sb, and Bi) yielding triaza-pnicta-butene analogues of the type R-N=N-N(R)-ECl_2 (R = Ter = 2,6- bis(2,4,6-trimethylphenyl)phenyl). Subsequent reduction of these dichloro-species afforded unprecedented four-membered group 15 heterocycles [E(μ-NTer)_2N] bearing one dicoordinate pnictogen and nitrogen atom. These N_3E rings represent species at the borderline between singlet biradicaloids and zwitterions with diminished reactivity compared to known singlet biradicaloids. The N_3P compound could be identified, while N_3As and N_3Sb species as well as the precursor compounds were fully characterized.