A Mixed Arsenic–Phosphorus Centered Biradicaloid

Main‐group singlet biradicaloids have been thoroughly investigated in the past two decades, especially derivatives of cyclobutane‐1,3‐diyl. However, in each of the known examples, the radical centers are identical. Therefore, we sought to prepare a mixed dipnictadiazanediyls with P and As bearing the radical character. To achieve this goal, the unprecedented cyclodichloro arsaphosphadiazane [ClP(μ‐NTer)₂AsCl] had to be prepared first. Treatment of [ClP(μ‐NTer)₂AsCl] with a halide‐abstracting agent led to the novel cyclic cation [P(μ‐NTer)₂AsCl]⁺, while reduction with magnesium afforded the first arsaphosphadiazanediyl [P(μ‐NTer)₂As].