Factors influencing the chelate linkage isomerism of some oxime complexes of nickel(II)

Abstract

¹ H N.m.r. and i.r. spectroscopy show that the (4-iminopentane-2,3-dione 3-oximato) ligand forms a five-membered chelate ring in (4-iminopentane-2,3-dione 3-oximato)(4-aminopent-3-en-2-onato)nickel(II) but a six-membered chelate ring in (3-methyliminobutan-2-one oximato)(4-iminopentane-2,3-dione 3-oximato)nickel(II). The stability of these and related mixed-ligand complexes of nickel(II) is attributed to the presence of intramolecular hydrogen bonding between the imino hydrogen atom of one ligand and the oximino oxygen atom of the other.