Structure and properties of iron-cyclam complex of 2-aminophenol

摘要

The cis-[Fe(cyclam)Cl_2]CI and trans-[Fe(cyclam)Cl_2]BF_4 complexes were prepared by a new synthetic procedure. These isomers were characterized by elemental analysis, electronic spectroscopy (Amu" = 238, 334 and ).mu" = 238, 302 and 355 nm for cis- and trans-[Fe(cyclam)Cl_2]+, respectively) and electrochemistry (E12 = 212 and 83 mV; vs. Ag I AgCI, KCl 3.5 M, 25°C 11 = 0.1 M NaTFA, pH 3.0 for cis- and trans-{Fe(cyclam)C12]+, respectively). The reaction ofcis-[Fe(cyclam)C12]+ isomer with 2-alJlinophe- no1 (catH_3) ligand yields the cis-[Fe(cyclam)(qH)] + complex, where (qH) is the quinonoid oxidized form of the (catH_3) ligand that is originated by an intramolecular electron transfer reaction. The cis-[Fe(cyclam)(qH)](PF6)2 complex crystallizes in the space group P21, with two different values for Fe- N bond length, due to the 0" and 1t distinct contributions. The electrochemical analysis of this species shows three one-electron sequential processes: E,12 (I) = -316 mV, El/2 (II) = + 361 mY and E,/2 (III)= + 1.013 mV assigned tc, (sqH/catH3), (qH/sqH) and (Fe(IrI)/Fe(II)) redox process, respectively.