N-heterocyclic compounds of phosphorus based ON N,N-disubstituted 9,10-phenanthrenediimines

N‑heterocyclic phospholes based on N,N¢-disubstituted 9,10-phenanthrenediimines were synthesized. Dimeric 1,3,2-diazaphospholes were obtained by reduction of 2-bromo diazaphospholes. In case phenanthrediimine with the most sterically hindrance, diphosphole can dissociate into phosphorus-centered radicals at record low temperatures (220 K) for this class. This behavior will allow the synthesis of new metal complexes and phosphorus-organic compounds under mild conditions.