Variable coordination behaviour of N-donor siloxane ligands. The structures of [M(1,3-bis(N-imidazoyl)propyl-1,1,3,3-tetramethyldisiloxane)2(NCS)2] (M = Mn, Ni) and [Ni(1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane)2(NCS)2]

The complexes [M(1,3-bis(N-imidazoyl)propyl-1,1,3,3-tetramethyldisiloxane)2(NCS)2] (M = Mn, Ni) are shown by X-ray studies to form monomers containing 16-membered chelate rings, but replacement of the imidazole donor groups by simple amino groups results in the formation of chains of 24-membered rings in [Ni(1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane)2(NCS)2].