Synthesis and structure of a tetranuclear nickel complex of a 40-membered macrocyclic octaamine-tetrathiophenolate ligand

The syntheses and characterization of tetranuclear Ni complexes [(L-2)Ni-4] [ClO4](4) (3) and [(L-2)Ni-4(NCS)(4)] (4) of a 40-membered macrocyclic octa amine-tetrathiophenolate ligand (L-2)(4-) are described. Single-crystal X-r ay structure analysis of 4 reveals well-separated molecules of the tetranuc lear isothiocyanate complex [(L-2)Ni-4(II)(NCS)(4)]. The four Ni centers ar e arranged in binuclear [N2Ni(mu (2)-SR)(2)NiN2(NCS)(2)] subunits containin g distorted square-planar NiN2S2 and distorted octahedral NiN2S2(NCS)(2) si tes. The fact that the two isothiocyanate groups at the octahedral Ni site are in trans positions can be ascribed to the large ring size of the macroc ycle.