Zum Kenntnisstand der 1,3,5‐Triaza‐2,4‐diphospha‐1,4‐pentadiene

On the Knowledge of the 1,3,5‐Triaza‐2,4‐diphospha‐1,4‐pentadienes Herrn Professor Heinrich Puff zum 70. Geburtstag gewidmet Nucleophilic substitution reactions of the chloro(arylimino)‐phosphane 1 yield the NH‐functional amino(imino)phosphanes Mes*NPNHR (R = Mes, Ad, CPh 3 ) 2d—f . Upon further reaction with 1 they are converted into the 1,3,5‐triaza‐2,4‐diphospha‐1,4‐pentadienes Mes*NPN(R)PNMes* (R = Mes, Ad) 4d, e and Mes*NPN(Mes*)PNCPh 3 5 . According to crystal structure determinations all compounds 4a, d, e, 5 exhibit S conformation in the solid state. In addition to the “ exo‐endo ” arrangement of the substituents ( 4a, 5 ) in the case of 4d, e the “ endo‐endo ” conformation is observed for the first time. In solution, 4d, e and 5 are subject to dynamic rearrangements, whose mechanism is proven by NMR studies of partially 15 N‐enriched samples. The reaction of 4a with NorM(CO) 4 (M = Cr, Mo) or Ni(CO) 4 yields the metallaazadiphosphetidine complexes 6a—c Mes*NPN( t Bu)PNMes*M(CO) n [M(CO) n = Cr(CO) 4 , Mo(CO) 4 , Ni(CO) 2 ]. The crystal structure of 6a (“ exo‐endo‐W ”) is described.