Contrasting bonding modes of a tridentate bis(oxazoline)phosphine ligand in cobalt and ironvs.palladium complexes: unprecedented N,N-coordination for a N,P,N ligand

Unexpected N,N-coordination of the potentially tridentate N,P,N-ligand bis(2-oxazolin-2,5,5-trimethyl)phenylphosphine occurs in Co(II) and Fe(II) complexes, in contrast to the P,N- or N,P,N-coordination modes observed in Pd(II) complexes; this leads to the formation of unprecedented eight-membered ring chelates.