Co(II) and Ni(II) complexes of linear tridentate nitrogenous ligands

The mono-ligand complexes of some linear tridentate nitrogenous ligands with nickel(II) and cobalt(II) salts are described. The compounds of formula [Ni- (ligand)X2] (X = Cl, Br, I or NCS) appear to be bridged octahedral compounds on the basis of electronic and infrared spectral measurements. On the other hand, spectral results indicate that the similar compounds of cobalt(II), are monomeric five-coordinate species. Magnetic data is reported for the compounds described, and details are given of infrared spectra for the pyridine ring vibration region, which indicate that in all cases the ligands act in a tridentate capacity