Mono-chelate complexes of pyridine-2-aldehyde 2′-pyridylhydrazone

Abstract

Mono-chelate complexes M(paphy)X₂(paphy = pyridine-2-aldehyde 2′-pyridylhydrazone; M = Mn, Co, Ni, Cu, Zn, Cd, Hg; X = halogen, pseudohalogen), Co(terpy)Cl₂, and Ni(terpy)Cl₂ are reported. The spectral and magnetic properties of three cobalt complexes and a nickel complex which are five-co-ordinate (square pyramidal) in the crystal state are discussed. The properties of the crystalline manganese, zinc, cadmium, and mercury complexes indicate that they may be five-co-ordinate. The properties of the nickel and one form of the cobalt complex, M(paphy)Cl₂, are consistent with halogen-bridged six-co-ordinate structures.