Synthesis and characterisation of cobalt, nickel, zinc and cadmium compounds with a pyridine-derived N3O2 macrocycle: Crystal and molecular structures of the macrocyclic ligand and Co(II), Ni(II) and Zn(II) complexes

The interaction of Co(II), Ni(II), Zn(II) and Cd(II) with L, a macrocycle containing an N3O2-donor set, has been investigated. The X-ray crystal structures of L, [CoL(NO3)2] (1), [NiL(NO3)2] (2) and [ZnL(H2O)(CH3CN)](ClO4)2 (5) have been determined. The metal atoms in the complexes are coordinated in an endomacrocyclic fashion with the Co and Ni atoms in six-coordinate environments comprised of the ligand N3-donor set and two nitrate ions, one monodentate and the other bidentate, giving a distorted octahedral geometry at the metal. In the Zn complex the metal is in a five-coordinate environment comprised of the ligand N3-donor set, a water molecule and an acetonitrile molecule, giving a trigonal bipyramidal geometry around the metal.