On The Nature of FeIV=Oaq in Aqueous Media: A DFT analysis

Basil Raju Karimadom; Dan Meyerstein; Haya Kornweitz

doi:10.1002/cphc.202300508

On The Nature of Fe^IV=O_aq in Aqueous Media: A DFT analysis

Basil Raju Karimadom, Dan Meyerstein, Haya Kornweitz

Department of Chemistry

Research output: Contribution to journal › Article › peer-review

Abstract

Fe^IV=O_aq is a key intermediate in many advanced oxidation processes and probably in biological systems. It is usually referred to as Fe^IV=O²⁺. The pKa's of Fe^IV=O_aq as derived by DFT are: pKa1=2.37 M06 L/6-311++G(d,p) (SDD for Fe) and pKa2=7.79 M06 L/6-311++G(d,p) (SDD for Fe). This means that in neutral solutions, Fe^IV=O_aq is a mixture of (H₂O)₄(OH)Fe^IV=O⁺ and (H₂O)₂(OH)₂Fe^IV=O. The oxidation potential of Fe^IV=O_aq in an acidic solution, E⁰{(H₂O)₅Fe^IV=O²⁺/Fe^III(H₂O)₆³⁺, pH 0.0} is calculated with and without a second solvation sphere and the recommended value is between 2.86 V (B3LYP/Def2-TZVP, with a second solvation sphere) and 2.23 V (M06 L/Def2-TZVP without a second solvation sphere). This means that Fe^IV=O_aq is the strongest oxidizing agent formed in systems involving Fe^VIO₄²⁻ even in neutral media.

Original language	English
Article number	e202300508
Journal	ChemPhysChem
Volume	24
Issue number	22
DOIs	https://doi.org/10.1002/cphc.202300508
State	Published - 16 Nov 2023

Keywords

E(Fe(IV)O+2H/Fe)
aqueous iron
density functional calculations
iron
pKa

ASJC Scopus subject areas

Atomic and Molecular Physics, and Optics
Physical and Theoretical Chemistry

Access to Document

10.1002/cphc.202300508

Cite this

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title = "On The Nature of FeIV=Oaq in Aqueous Media: A DFT analysis",

abstract = "FeIV=Oaq is a key intermediate in many advanced oxidation processes and probably in biological systems. It is usually referred to as FeIV=O2+. The pKa's of FeIV=Oaq as derived by DFT are: pKa1=2.37 M06 L/6-311++G(d,p) (SDD for Fe) and pKa2=7.79 M06 L/6-311++G(d,p) (SDD for Fe). This means that in neutral solutions, FeIV=Oaq is a mixture of (H2O)4(OH)FeIV=O+ and (H2O)2(OH)2FeIV=O. The oxidation potential of FeIV=Oaq in an acidic solution, E0{(H2O)5FeIV=O2+/FeIII(H2O)63+, pH 0.0} is calculated with and without a second solvation sphere and the recommended value is between 2.86 V (B3LYP/Def2-TZVP, with a second solvation sphere) and 2.23 V (M06 L/Def2-TZVP without a second solvation sphere). This means that FeIV=Oaq is the strongest oxidizing agent formed in systems involving FeVIO42− even in neutral media.",

keywords = "E(Fe(IV)O+2H/Fe), aqueous iron, density functional calculations, iron, pKa",

author = "Karimadom, {Basil Raju} and Dan Meyerstein and Haya Kornweitz",

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AU - Karimadom, Basil Raju

AU - Meyerstein, Dan

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PY - 2023/11/16

Y1 - 2023/11/16

N2 - FeIV=Oaq is a key intermediate in many advanced oxidation processes and probably in biological systems. It is usually referred to as FeIV=O2+. The pKa's of FeIV=Oaq as derived by DFT are: pKa1=2.37 M06 L/6-311++G(d,p) (SDD for Fe) and pKa2=7.79 M06 L/6-311++G(d,p) (SDD for Fe). This means that in neutral solutions, FeIV=Oaq is a mixture of (H2O)4(OH)FeIV=O+ and (H2O)2(OH)2FeIV=O. The oxidation potential of FeIV=Oaq in an acidic solution, E0{(H2O)5FeIV=O2+/FeIII(H2O)63+, pH 0.0} is calculated with and without a second solvation sphere and the recommended value is between 2.86 V (B3LYP/Def2-TZVP, with a second solvation sphere) and 2.23 V (M06 L/Def2-TZVP without a second solvation sphere). This means that FeIV=Oaq is the strongest oxidizing agent formed in systems involving FeVIO42− even in neutral media.

AB - FeIV=Oaq is a key intermediate in many advanced oxidation processes and probably in biological systems. It is usually referred to as FeIV=O2+. The pKa's of FeIV=Oaq as derived by DFT are: pKa1=2.37 M06 L/6-311++G(d,p) (SDD for Fe) and pKa2=7.79 M06 L/6-311++G(d,p) (SDD for Fe). This means that in neutral solutions, FeIV=Oaq is a mixture of (H2O)4(OH)FeIV=O+ and (H2O)2(OH)2FeIV=O. The oxidation potential of FeIV=Oaq in an acidic solution, E0{(H2O)5FeIV=O2+/FeIII(H2O)63+, pH 0.0} is calculated with and without a second solvation sphere and the recommended value is between 2.86 V (B3LYP/Def2-TZVP, with a second solvation sphere) and 2.23 V (M06 L/Def2-TZVP without a second solvation sphere). This means that FeIV=Oaq is the strongest oxidizing agent formed in systems involving FeVIO42− even in neutral media.

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