New specific routes to 1,2-diphosphete-, 1,2,4-triphosphol-, and 1,2,4-trip
hospholyl-pi-complexes are reported, which are based on dichloro-l,2-diphos
phetene and I-stannyl-l,2,4-triphosphol as the heterocyclic educts. Details
are given for Sn, Mn, Fe, and Co complexes. ESR-data of paramagnetic 1,2,4
-triphospholyl sandwich complexes of Co and Mn proof the absence of degener
ate SOMOs in these cases.