Kinetics of the chemical oxidation of (5,10,15,20-tetraphenyl-21H,23H-porphinato)(chloro)(aqua)iridium(III)

• Published in: Russian Journal of Physical Chemistry A Vol. 90; no. 1; pp. 37 - 42
• Main Authors: Tyulyaeva, E. Yu, Bichan, N. G., Mozhzhukhina, E. G., Lomova, T. N.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 2016
• Subjects: Chemical Kinetics and Catalysis; Chemistry; Chemistry and Materials Science; Physical Chemistry; iridium; chemical oxidation; tetraphenylporphin; kinetics; π-radical cations; complexes
• ISSN: 0036-0244; 1531-863X
• DOI: 10.1134/S0036024416010325

The oxidation of (Cl)(H 2 O)IrTPP with atmospheric oxygen in the presence of concentrated H 2 SO 4 accompanied by coordination of molecular O 2 and substitution of axial ligands was studied spectrophotometrically. In 16.785–18.09 М H 2 SO 4 at 298–318 K, (Cl)(H 2 O)IrTPP experienced two single-electron oxidations in sequence: with an increase in the oxidation state of the iridium cation and with formation of the π-radical cation form (HSO 4 )Ir IV TPP •+ oxidized at the aromatic ligand ( k 298 = 7.2 × 10 –6 mol –1 L s –1 ). Referring to the literature data on the oxidation of (Cl)(H 2 O)IrTPP in AcOH and CF 3 COOH, it was shown that the medium acidity and the nature of the axial ligands affect the electron removal site in the chemical oxidation of (Cl)(H 2 O)IrTPP with atmospheric oxygen in proton-donor solvents.