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* See footnotes to Table 1. The results of quantum-chemical B3LYP/LANL2DZ_6-31G«« calculation of the total energy E;ora, Zero-point energy E, and entropy 5S5,, for molecular reagents in the Fentor reaction (for the iron ions we used a model of the octahedral aquacomplexes with two groups of soz in the coordination sphere): H30* + HOOH + Fe?*(SO; )2(H20)2 < Fe?*(SO2- )a(H20)2 + OH + 2H20.

Table 1 * See footnotes to Table 1. The results of quantum-chemical B3LYP/LANL2DZ_6-31G«« calculation of the total energy E;ora, Zero-point energy E, and entropy 5S5,, for molecular reagents in the Fentor reaction (for the iron ions we used a model of the octahedral aquacomplexes with two groups of soz in the coordination sphere): H30* + HOOH + Fe?*(SO; )2(H20)2 < Fe?*(SO2- )a(H20)2 + OH + 2H20.

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This article appeared in a journal published by Elsevier. The attachec copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Provided for non-commercial research and education use. Not for reproduction, distribution or commercial use.
This article appeared in a journal published by Elsevier. The attachec copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Provided for non-commercial research and education use. Not for reproduction, distribution or commercial use.
? In square brackets the values of the experimental data S34, for the gas phase are presented [http://webbook.nist.gov/chemistry]. > The used energy units ratio: 1 a.u. = 627.544 kcal, 1 kcal = 4184 kJ. The calculated total energy Etorai, vibrational zero-point energy E, and entropy S,, for molecular reagents in the Fenton reaction: H30* + HOOH + Fe?*(H20)¢ — Fe** (H20)¢ + OH + 2H20. For the iron ions the “pure” octahedral aqua complex models (Fig. 1) are used. All results are obtained by quantum-chemical B3LYP/Lanl2DZ;6-31G«« calculations.
? In square brackets the values of the experimental data S34, for the gas phase are presented [http://webbook.nist.gov/chemistry]. > The used energy units ratio: 1 a.u. = 627.544 kcal, 1 kcal = 4184 kJ. The calculated total energy Etorai, vibrational zero-point energy E, and entropy S,, for molecular reagents in the Fenton reaction: H30* + HOOH + Fe?*(H20)¢ — Fe** (H20)¢ + OH + 2H20. For the iron ions the “pure” octahedral aqua complex models (Fig. 1) are used. All results are obtained by quantum-chemical B3LYP/Lanl2DZ;6-31G«« calculations.
LI. Zakharov et al./Computational and Theoretical Chemistry 964 (2011) 94-99 Fig. 1. Geometry of the octahedral aquacomplexes of iron ions optimized with the density functional (B3LYP) quantum-chemical calculations in vacuum with the Lanl2L and 6-31G« basis sets. (D2,-symmetry is obtained, bond distances are in A). (a) ferrous aquacomplex — Fe**(H20),, (b) ferric aquacomplex - Fe?*(H20)g.
LI. Zakharov et al./Computational and Theoretical Chemistry 964 (2011) 94-99 Fig. 1. Geometry of the octahedral aquacomplexes of iron ions optimized with the density functional (B3LYP) quantum-chemical calculations in vacuum with the Lanl2L and 6-31G« basis sets. (D2,-symmetry is obtained, bond distances are in A). (a) ferrous aquacomplex — Fe**(H20),, (b) ferric aquacomplex - Fe?*(H20)g.
* See of signature to Table 1. The results of quantum-chemical B3LYP/LANL2DZ_6-31G«« calculation of the total energy Etotal, Zero-point energy E, and entropy S5,, for molecular reagents in the Fenton reaction (for the iron ions we used a model of the octahedral aquacomplexes with one group of So; in the coordination sphere): H30* + HOOH + Fe**(SO4 )(H20)4 Fe?*(SO% )(H20)4 + OH + 2H20.
* See of signature to Table 1. The results of quantum-chemical B3LYP/LANL2DZ_6-31G«« calculation of the total energy Etotal, Zero-point energy E, and entropy S5,, for molecular reagents in the Fenton reaction (for the iron ions we used a model of the octahedral aquacomplexes with one group of So; in the coordination sphere): H30* + HOOH + Fe**(SO4 )(H20)4 Fe?*(SO% )(H20)4 + OH + 2H20.
Fig. 2. Optimized geometry (Ci-symmetry, bond distances are in A) octahedral aquacomplexes of iron ions with one group of SO} in the coordination sphere (a-Fe?*(SO% )(H20)4, b-Fe?*(SO} )(H20)4) in the quantum-chemical B3LYP/LANL2DZ_6-31G+ calculation model Fenton reaction: H30* +HOOH + Fe?*(SO% )(H20)4 Fe?*(SO7” )(H2O)4 + OH + 2H20. LI. Zakharov et al./Computational and Theoretical Chemistry 964 (2011) 94-99
Fig. 2. Optimized geometry (Ci-symmetry, bond distances are in A) octahedral aquacomplexes of iron ions with one group of SO} in the coordination sphere (a-Fe?*(SO% )(H20)4, b-Fe?*(SO} )(H20)4) in the quantum-chemical B3LYP/LANL2DZ_6-31G+ calculation model Fenton reaction: H30* +HOOH + Fe?*(SO% )(H20)4 Fe?*(SO7” )(H2O)4 + OH + 2H20. LI. Zakharov et al./Computational and Theoretical Chemistry 964 (2011) 94-99
LI. Zakharov et al./Computational and Theoretical Chemistry 964 (2011) 94-99 Fig. 3. The optimized geometry (C;-symmetry, bond distances are in A) octahedral aquacomplexes of iron ions with two groups of SO} in the coordination sphere (a- Fe?*(SO% )2(H20)2, b-Fe?*(SO} )o(H20)2) in the quantum-chemical B3LYP/LANL2DZ_6-31G** calculation model Fenton reaction: H30* +HOOH + Fe?*(SO% )2(H20)2 Fe?*(SO% )2(H20)2 + OH + 2H20 .
LI. Zakharov et al./Computational and Theoretical Chemistry 964 (2011) 94-99 Fig. 3. The optimized geometry (C;-symmetry, bond distances are in A) octahedral aquacomplexes of iron ions with two groups of SO} in the coordination sphere (a- Fe?*(SO% )2(H20)2, b-Fe?*(SO} )o(H20)2) in the quantum-chemical B3LYP/LANL2DZ_6-31G** calculation model Fenton reaction: H30* +HOOH + Fe?*(SO% )2(H20)2 Fe?*(SO% )2(H20)2 + OH + 2H20 .
* After reaction the solvent grows turbid. The turbidity is connected with the BaSO, precipitation. The measured rate constants of the hydrogen peroxide decomposition (the absolute errors are estimated by the least square procedure).
* After reaction the solvent grows turbid. The turbidity is connected with the BaSO, precipitation. The measured rate constants of the hydrogen peroxide decomposition (the absolute errors are estimated by the least square procedure).
Fig. 4. The calculated Gibbs energy of the Fenton reactions (1) and (2) as a function of the number of sulfate anions (n = 0, 1, 2) in the coordination sphere of the aqua iron ions. The most favorable thermodynamic region for the catalytic Fenton cycle (with the reversible redox transition of iron ions Fe?* — Fe?*) is marked by the dotted line.
Fig. 4. The calculated Gibbs energy of the Fenton reactions (1) and (2) as a function of the number of sulfate anions (n = 0, 1, 2) in the coordination sphere of the aqua iron ions. The most favorable thermodynamic region for the catalytic Fenton cycle (with the reversible redox transition of iron ions Fe?* — Fe?*) is marked by the dotted line.
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