Nickel(II) and copper(II) complexes of macrocyclic and acyclic Schiff-baseligands derived from new asymmetrical tripodal tetraamines and 2,6-diacetylpyridine

The asymmetrical tripodal 4,2,2'-tetraamine N{(CH2)(4)NH2}{(CH2)(2)NH2}(2) bee, 3,2,2'-tetraamine N{(CH2)(3)NH2} {(CH2)(2)NH2}(2) pee, and 3,3',2-tetr aamine N{(CH2)(3)NH2}(2){(CH2)(2)NH2} ppe ligands have been prepared. In th e presence of Cu-II or Ni-II ions, these ligands condense with 2,6-diacetyl pyridine. In some cases, cyclization occurs and new isomers of CR-type with a pendant primary amine group are formed. In the other cases ring closure does not occur and coordinated acyclic hexadentate ligands have been isolat ed. At room temperature and in absolute methanol the latter acyclic complex es are usually the only products. I.r., u.v.-vis., reflectance spectra and magnetic moments for the complexes were recorded.