The electrochemistry and spectroscopic properties of iron corroles having an NO axial ligand and NO2 at one or two β-pyrrole positions of the macrocycle were investigated in benzonitrile, pyridine and dichloromethane containing 0.1 M tetra-n-butylammonium perchlorate (TBAP) as supporting electrolyte. In addition to the β- pyrrole NO2 groups, the compounds also contain NO2, CH3 or OCH3 substituents at the three meso-phenyl rings of the macrocycle. Structures of the investigated iron corroles are shown in Chart 1. Each iron(III) corrole exhibits one oxidation and up to five reductions, depending on the solvent, number and position of nitro groups and specific substituents (R groups) on the corrole macrocycle. The first reduction is reversible and involves an Fe3+/Fe2+ process which occurs in the range of E1/2 values between -0.35 and +0.31 V vs SCE. Further reductions at the iron center, at the NO axial ligand, or at the π ring system of the corrole macrocycle occur at more negative potentials. Several oxidations are also observed at potentials between +0.82 and +1.37 V vs SCE. Thinlayer UV-visible and IR spectroelectrochemistry, along with ESR spectroscopy were used to study the site of electron transfer. Several free-base nitrocorroles with similar macrocycles were also investigated as to their redox properties and comparisons are made between this series of compounds and previously investigated free-base corroles having electron donating or electron withdrawing substituents at the three meso positions of the phenyl rings in triphenyl substituted corroles.1 Comparisons are also made between the metallated corroles in Chart 1 and metallocorroles containing copper, 2 germanium,2 silver3 or other central metal ions.
Tortora, L. (2012). Electroreduction of Iron and Free-Base Nitrocorroles in Non-Aqueous Media. MEETING ABSTRACTS, MA2012-01(35), 1289-1289.
Electroreduction of Iron and Free-Base Nitrocorroles in Non-Aqueous Media
TORTORA, LUCA
2012-01-01
Abstract
The electrochemistry and spectroscopic properties of iron corroles having an NO axial ligand and NO2 at one or two β-pyrrole positions of the macrocycle were investigated in benzonitrile, pyridine and dichloromethane containing 0.1 M tetra-n-butylammonium perchlorate (TBAP) as supporting electrolyte. In addition to the β- pyrrole NO2 groups, the compounds also contain NO2, CH3 or OCH3 substituents at the three meso-phenyl rings of the macrocycle. Structures of the investigated iron corroles are shown in Chart 1. Each iron(III) corrole exhibits one oxidation and up to five reductions, depending on the solvent, number and position of nitro groups and specific substituents (R groups) on the corrole macrocycle. The first reduction is reversible and involves an Fe3+/Fe2+ process which occurs in the range of E1/2 values between -0.35 and +0.31 V vs SCE. Further reductions at the iron center, at the NO axial ligand, or at the π ring system of the corrole macrocycle occur at more negative potentials. Several oxidations are also observed at potentials between +0.82 and +1.37 V vs SCE. Thinlayer UV-visible and IR spectroelectrochemistry, along with ESR spectroscopy were used to study the site of electron transfer. Several free-base nitrocorroles with similar macrocycles were also investigated as to their redox properties and comparisons are made between this series of compounds and previously investigated free-base corroles having electron donating or electron withdrawing substituents at the three meso positions of the phenyl rings in triphenyl substituted corroles.1 Comparisons are also made between the metallated corroles in Chart 1 and metallocorroles containing copper, 2 germanium,2 silver3 or other central metal ions.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.