Synthesis of 1,2,4-triaza-3,5-diphospholidines

1,2,4-Triaza-3,5-diphospholidines were synthesized by highly selective cyclization reactions between N,N-bis[chloro(phenyl)phosphino]methylamine and 1,2-disubstituted hydrazines. Three examples of molecular structures are discussed against the background of configurational isomers and the potential of the title compounds as versatile cyclic ligands with chelating P–N–P motif.