Binuclear metal complexes. LIII [1]. Synthesis and proteins of iron(II) and iron(III) complexes of strati-bis schiff bases

Abstract

Strati-bis iron(II) and iron(III) complexes, Fe 2(sata), Fe 2(sacta), Fe 2(sata)Cl 2, and Fe 2(sacta)Cl 2, have been prepared and characterized, where H 4sata denotes 1,2,3,4-tetrakis(salycylideneamino)-2, 3-dimethylbutane and H 4sacta 1,2-bis(salicylideneamino) 1,2-bis(salicylideneaminomethyl)cyclohexane. In comparison with the relevant mononuclear iron(II) complexes, Fe 2(sata) and Fe 2(sacta) were shown to be less sensitive to molecular oxygen. Each differential pulse polarogram of the iron(II) and iron(III) complexes revealed two waves attributable to the reduction at the metal. The higher potential wave was tentatively assigned to the one-electron transfer process, Fe(III)Fe(III)/Fe(III)Fe(II), of the stacked conformer, while the lower potential wave to the two-electron transfer process, Fe(III)Fe(III)/Fe(II)Fe(II), of the non-staked conformer. The facile reduction of iron(III) in the stacked conformer has been attributed to the emergence of an electron delocalization over the whole molecule due to the stacking of the two coordination planes.