Mixed-ligand complexes of Co(II) and Cu(II) with pyrazolonic Mannich bases and 2-aminobenzothiazole

Mixed-ligand complexes of the type M2L(TAB)(n)X-4 [L = N,N'-bis(4-antipyryl-methyl)piperazine (BAMP), or N,N'-tetra(4-antipyrylmethyl)-1,2-diaminoethane (TAMEN) and 2-aminobenzothiazole (TAB), X = NCS or ClO4, M = Co, n = 2, or M = Cy n = 4] were synthesized and investigated. The IR and Raman spectra revealed that the ligands L are coordinated through the carbonyl oxygen atom of the antipyrine and the nitrogen atom of the piperazine or 1,2-ethanediamine bridge, except in Cu-2(TAMEN)(TAB)(4)(ClO4)(4), in which case TAMEN is coordinated to the metal only through the carbonyl oxygen. Steric considerations explain the bonding of TAB through the exocyclic or endocyclic nitrogen.