Heteroleptic diphosphenes and arsaphosphenes bearing neutral and anionic N-heterocyclic carbenes.

The reaction of the phosphorus and arsenic dihalides (WCA-IDipp)ECl2 (E = P, As) that bear an anionic N-heterocyclic carbene ligand with a weakly coordinating borate moiety (WCA = B(C6F5)3, IDipp = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene) with (IDipp)PSiMe3 afforded the monochlorides (WCA-IDipp)E(Cl)P(IDipp), which can be transformed into the cationic dipnictenes [(WCA-IDipp)EP(IDipp)][GaCl4] or neutral radicals [(WCA-IDipp)EP(IDipp)] by treatment with GaCl3 or reduction with 1,4-bis(trimethylsilyl)-1,4-dihydropyrazine.