| Abstract |
The diaminobis(phenolato) salan ligand precursors,N,N -dimethyl-N,N -bis-(2-hydroxy-3-X-5-Y-6-Z-benzyl)-1,2-diaminoethane \X =Pr-i, Y = Cl, Z = Me (H2L1); X = OCH3, Y = allyl, Z = H (H2L2)\ andN,N -bis-(2-hydroxy-3-X-5-Y-6-Z-benzyl)-4-methylimidazolidine \X =Pr-i, Y = Cl, Z = Me (H2L3); X =Bu-t, Y = CH3, Z = H (H2L4)\ and their corresponding Cu(ii) complexes are synthesized and characterized. [Cu(L-1)(DMSO)] and [Cu(L-2)] show the expected geometry and coordination behavior. However, upon coordination to the Cu(ii) centre in the presence of CH3OH, ring cleavage in H(2)L(3)and H(2)L(4)occurs. Subsequent and unexpected coordination of thein situformed pendant acetal fragment of the new ligand, formedviaring opening, leads to the formation of the phenolato bridged dimeric Cu(ii) complex, [Cu(L-3A)](2), and a monomeric Cu(ii) complex [Cu(L-4A)], where an extra acetal fragment is present as a pendant group. An outline of the probable mechanism for this process is proposed. The superoxide dismutase activity of the Cu(ii) complexes is also investigated. |
