and 2.2'-bis-(NN-dimethylamino)azobenzene (Me,N-ab-NMe,) form complexes with the chlorides or bromides of bivalent iron, cobalt, nickel, copper, and zinc having the general formula MLX,. The stereochemistry of these complexes has been studied by means of magnetic and spectrophotometric measurements. With the exception of Cu(Me,N-baphen-NMe,)CI, and Cu( Me,N-ab-NMe,) CI , , which attain six-co-ordination through chlorine bridging linkages, all are five-co-ordinate complexes.THE isolation of high-spin five-co-ordinate complexes of metals from manganese(@ to zinc(@ by the interaction of the metal salts and alkyl-substituted polyamines such as N(and HN(CH,*CH,*NEtJ,3 led to the conclusion l s 3 that, for the formation of five-co-ordinate complexes, the ligand must be bulky and multidentate in order that crowding around the metal ion should M. Ciampolini and N. Nardi, Inorg. Chem., 1966, 5, 41. a M. Ciampolini and G. P. Speroni, Inorg. Chem., 1966, 5, 45. 2. Dori and H. B. Gray, J . Amer. Chem. SOC., 1966, 88, 1394. prevent a six-co-ordinate configuration being attained. Following our work on the cobalt complexes of Schiff base 4 and azo-ligands 5 containing alkylamino-groups we have tested the generality of the above conclusion by examining the complexes formed between bivalent transition-metal halides and such ligands bearing only tertiary nitrogen donor atoms. The ligands which we have investigated are N-( (3-N'N'-dimethylaminoethy1)pyridinaldimine (I) (paenMeJ , N-(2'-N'N'-dimethylaminophenyl) pyridinaldimine (11) (paphen-P. Bamfield, J .