Coordination compounds of hydrazine derivatives with transition metals. Part 20. Nickel(II) chelates witho-hydroxy ando-methoxy-benzaldehyde aroylhydrazones. An example of coordination isomerism

Abstract

A series of monoligand nickel(II) chelates Ni(SalC6H4X) · 3 H2O containing salicylaldehyde aroylhydrazones H2SalC6H4X were isolated and characterized. The correspondingo-methoxyhenzaldcliyde aroylhydrazones (HMeOBhC6H4X) react with nickel(II) acetate to give isomeric red and green chelates of stoichiometry M(MeOBhC6H4X)2. The red isomers were assumed to possess a square planar arrangement with the hydrazone molecule acting, as a mononegative bidentate ligand, whereas an octahedral structure was assigned to the green isomer with the hydrazone molecule acting as mononegative tridentale ligand. The pyridine and 1,10-phenanthrolinc adducts of the complexes were characterizcd.