Synthesis, characterization and SOD-like activities of manganese-containing complexes with N,N,N ',N '-tetrakis(2 '-benzimidazolyl methyl)-1,2-ethanediamine (EDTB)

A series of manganese-containing mononuclear and binuclear model compounds of superoxide dismutase (SOD) coordinated by a polydentate ligand N,N,N',N' -tetrakis(2'-benzimidazolyl methyl)-1,2-ethanediamine (EDTB) have been synt hesized and characterized. The SOD-like activities of these complexes have been measured by means of modified nitroblue tetrazolium (NBT) photoreducti on, and the rate constants k(Q) of catalytic superoxide dismutation are in the range 6.96 x 10(6)-2.32 x 10(7) l mol(-1) s(-1). In complex [Mn(EDTB)(A c)](Ac).C2H5OH the coordination environment around the manganese(II) ion ca n be described as a highly-distorted capped octahedron with an oxygen atom of the bidentate acetate ion at the capping site. This complex is the first example in which EDTB acts as a pentadentate ligand with one non-ligating benzimidazole group. (C) 2001 Published by Elsevier Science Ltd.