Synthesis of mu-oxo and bis(mu-alkoxo) bridged diiron(III) complexes usinga tripodal ligand, bis(2-benzimidazolylmethy)ethanolamine with mixed N/O donor atoms

A mu-oxo diiron(LU) complex and two bis(mu-alkoxo) diiron(lll) complexes wi th biomimetic tripodal ligand containing mixed N/O donor atoms were synthes ized using a mononuclear iron(III) complex as starting material. Depending on the amounts and kinds of bases used, we obtained various kinds of diiron (III) complexes. The reaction of [Fe-III(Hbbea)Cl-2]Cl, 1, with an equivale nt amount of KO2 or NaOAc produced [(Fe2O)-O-III(Hb-bea)(2)Cl-2]Cl-2, 2. An additional equivalent amount of NaOBz or NaOAc converts complex 2 to compl ex 3 or complex 4 depending on the base used. The addition of two equivalen t amounts of NaOBz or NaOAc directly converts complex 1 to [Fe-2(III)(bbea) (2)(OBz)(2)]Cl-2, 3, or [Fe-2(III)(bbea)(2)(OAc)(2)]CL2, 4, depending on th e base used. Crystal data are as follows: [(Fe2O)-O-III(Hbbea)(2)Cl-2]Cl-2, 2: monoclinic space group P21(/)n, a = 8.421 (1) Angstrom, b = 18.416 (2) Angstrom, c = 13.736 (1) Angstrom, beta = 104.870 (7)degrees, V = 2058.9 (4 ) Angstrom(3), Z = 2, R1 = 0.0469 and wR2 = 0.1201 for reflections with I > 2 sigma(I).