Closely related macrocyclic and acyclic tridentate, pyridine derivatives, containing sulphur, and their complexes. Crystal structures of {dichloro-3,10-dithia-16-azabicyclo[10.3.1]hexadeca-1(16),12,14-triene} copper(II) and [2,6-bis(ethyithiomethyl)pyridine]dichlorocopper(II)

Four closely related, tridentate, pyridine derivatives, containing sulphur, three of them macrocyclic, 3,10-dithia-16-azabicyclo[10.3.1]hexadeca-1 (16),12,14-triene (L¹), 3,8-dithia-14-azabicyclo-[8.3.1]tetradeca-1(14),10,12-triene (L²), 3,7-dithia-13-azabicyclo[7.3.1]trideca-1(13),9,11-triene (L³), and one acyclic, 2,6-bis(ethylthiomethyl)pyridine (L⁴), have been prepared. All contain the same co-ordination elements (NS<inf>2</inf>) structurally placed in the same fashion, sulphur-methylene-pyridine-methylene-sulphur. Copper complexes of all the ligands and the palladium complex of L¹ have also been prepared. The molecular structures of the complexes [CuL¹Cl<inf>2</inf>] and [CuL⁴Cl<inf>2</inf>] are described. The latter is monoclinic, space group I2/c, with a = 14.669(6), b = 7.418(4), c = 29.412(8) Å, β = 103.03(4)°, and Z = 8. The former is monoclinic, space group P2/a with a = 14.677(9), b = 7.555(1), c = 29.969(4) Å, β = 101.00(2)°, and Z = 8. The different reactivity of the macrocycle ligand L¹ with respect to that of L⁴ is discussed.