ON THE KNOWLEDGE OF THE 1,3,5-TRIAZA-2,4-DIPHOSPHA-1,4-PENTADIENES

Nucleophilic substitution reactions of the chloro(arylimino)-phosphane 1 yield the NH-functional amino(imino)phosphanes Mes*NPNHR (R = Mes, Ad, CPh3) 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*)PNCPh3 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 N-15-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(tBu)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.