The synthesis and characterization of a novel (E,E)-dioxime and its mono- and polynuclear complexes

A bidentate (E,E)-dioxime ligand, 2,3-bis(hydroxyimino)-7,16-dioxa-10,13-bis(toluene-p-sulfonyl)-1,4,10,13-tetrazacyclooctadecane (H2L), has been synthesized by the addition reaction of (E,E)-dichloroglyoxime with 1,14-diamino-6,9-bis(toluene-p-sulfonyl)-3,12-dioxa-6,9-diazatetradecane. The free macrocyclic ligand is neutral and coordinates with nickel(II) and copper(II) through its hydroxyimino nitrogen donors in the equatorial position by the loss of one of the oxime protons, with the concomitant formation of two intramolecular hydrogen per oxime molecule. The series of homo-and heterotrinuclear complexes Cu-II, or Ni-3(II), and (CuNi2II)-Ni-II, or (NiCu2II)-Cu-II, respectively, containing the oximato tetra-anion as a bridging ligand and 2,2'-bipyridine (L') or 1,10-phenanthroline (L ") as end-capping ligands have been synthesized by using [Cu(HL)(2)] or [Ni(HL)(2)] as the ligand for the ML "(+) center. The macrocyclic ligand and its transition metal complexes have been characterized on the basis of H-1, C-13 NMR, IR, UV-VIS and MS spectroscopy and elemental analytical data.