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

Abstract

A μ-oxo diiron(III) complex and two bis(μ-alkoxo) diiron(III) complexes with biomimetic tripodal ligand containing mixed N/O donor atoms were synthesized 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)Cl2]Cl, 1, with an equivalent amount of KO2 or NaOAc produced [Fe(III)2O(Hbbea)2Cl2]Cl2, 2. An additional equivalent amount of NaOBz or NaOAc converts complex 2 to complex 3 or complex 4 depending on the base used. The addition of two equivalent amounts of NaOBz or NaOAc directly converts complex 1 to [Fe(III)2(bbea)2(OBz)2]Cl2, 3, or [Fe(III)2(bbea)2(OAc)2]Cl2, 4, depending on the base used. Crystal data are as follows: [Fe(III)2O(Hbbea)2Cl2]Cl2, 2: monoclinic space group P21/n, a = 8.421 (1) A, b = 18.416 (2) A, c = 13.736 (1) A, β= 104.870 (7)°, V = 2058.9 (4) A3, Z = 2, R1 = 0.0469 and wR2 = 0.1201 for reflections with I > 2σ(I).