TY  - JOUR
AU  - Etinski, Mihajlo
AU  - Stanković, Ivana
AU  - Puthenkalathilc, Rakesh C.
AU  - Ensing, Bernd
PY  - 2020
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/3396
AB  - The diiron benzenedithiolato carbonyl complex is a biomimetic catalyst for proton reduction whose catalytic pathways depend on the solvent properties and the proton donor acidity. Previous studies showed that the initial steps in electrocatalytic generation of dihydrogen in acetonitrile involve a two-electron reduction followed by protonation, but the structures and physical properties of other intermediates are not known. We have performed a systematic quantum chemical analysis of the reduced and protonated complexes with benzenedithiolato and benzenediselenato ligands that can be formed by addition of up to three electrons and/or protons. The exchange of the sulfur atoms by selenium increases the basicity of the iron atoms but is not favorable for the protonation of the chalcogen atoms. Our results show that the most stable singly protonated complexes possess the proton in a bridging position between both irons, irrespective of the total complex charge. The second proton can be attached to a chalcogen atom or to an iron atom in a terminal position, depending on the complex charge. The most stable isomers of the triply protonated complexes have protons in the bridging and terminal positions as well as one proton bound to a chalcogen atom. Standard reduction potentials and acidities of all examined complexes were computed. We also discussed possible intermediates and reaction pathways in the electrocatalytic proton reduction to molecular hydrogen formation.
PB  - Royal Society of Chemistry
T2  - New Journal of Chemistry
T1  - A DFT study of structure and electrochemical properties of diiron-hydrogenase models with benzenedithiolato and benzenediselenato ligands
VL  - 44
IS  - 3
SP  - 932
EP  - 941
DO  - 10.1039/c9nj04887a
ER  - 

@article{
author = "Etinski, Mihajlo and Stanković, Ivana and Puthenkalathilc, Rakesh C. and Ensing, Bernd",
year = "2020",
abstract = "The diiron benzenedithiolato carbonyl complex is a biomimetic catalyst for proton reduction whose catalytic pathways depend on the solvent properties and the proton donor acidity. Previous studies showed that the initial steps in electrocatalytic generation of dihydrogen in acetonitrile involve a two-electron reduction followed by protonation, but the structures and physical properties of other intermediates are not known. We have performed a systematic quantum chemical analysis of the reduced and protonated complexes with benzenedithiolato and benzenediselenato ligands that can be formed by addition of up to three electrons and/or protons. The exchange of the sulfur atoms by selenium increases the basicity of the iron atoms but is not favorable for the protonation of the chalcogen atoms. Our results show that the most stable singly protonated complexes possess the proton in a bridging position between both irons, irrespective of the total complex charge. The second proton can be attached to a chalcogen atom or to an iron atom in a terminal position, depending on the complex charge. The most stable isomers of the triply protonated complexes have protons in the bridging and terminal positions as well as one proton bound to a chalcogen atom. Standard reduction potentials and acidities of all examined complexes were computed. We also discussed possible intermediates and reaction pathways in the electrocatalytic proton reduction to molecular hydrogen formation.",
publisher = "Royal Society of Chemistry",
journal = "New Journal of Chemistry",
title = "A DFT study of structure and electrochemical properties of diiron-hydrogenase models with benzenedithiolato and benzenediselenato ligands",
volume = "44",
number = "3",
pages = "932-941",
doi = "10.1039/c9nj04887a"
}

Etinski, M., Stanković, I., Puthenkalathilc, R. C.,& Ensing, B.. (2020). A DFT study of structure and electrochemical properties of diiron-hydrogenase models with benzenedithiolato and benzenediselenato ligands. in New Journal of Chemistry
Royal Society of Chemistry., 44(3), 932-941.
https://doi.org/10.1039/c9nj04887a

Etinski M, Stanković I, Puthenkalathilc RC, Ensing B. A DFT study of structure and electrochemical properties of diiron-hydrogenase models with benzenedithiolato and benzenediselenato ligands. in New Journal of Chemistry. 2020;44(3):932-941.
doi:10.1039/c9nj04887a .

Etinski, Mihajlo, Stanković, Ivana, Puthenkalathilc, Rakesh C., Ensing, Bernd, "A DFT study of structure and electrochemical properties of diiron-hydrogenase models with benzenedithiolato and benzenediselenato ligands" in New Journal of Chemistry, 44, no. 3 (2020):932-941,
https://doi.org/10.1039/c9nj04887a . .

TY  - JOUR
AU  - Milovanović, Branislav
AU  - Ilić, Jelica
AU  - Stanković, Ivana
AU  - Popara, Milana
AU  - Petković, Milena
AU  - Etinski, Mihajlo
PY  - 2019
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/2949
AB  - Understanding the basic chemistry between highly reactive free radicals and dopamine is an important step in characterizing the antioxidative activity of catecholamine neurotransmitters. In this work, we simulated the reactions between dopamine and hydroxyl, peroxyl and methoxy radicals in aqueous solution by employing first principle molecular dynamics based on density functional theory and the BLYP functional. The simulations provide mechanistic insight into the reaction mechanisms but underestimate reaction timescales. The failure of the BLYP functional to address the formal hydrogen atom transfer barriers between dopamine and free radicals is attributed to the self-interaction error.
PB  - Elsevier
T2  - Chemical Physics
T1  - A simulation of free radicals induced oxidation of dopamine in aqueous solution
VL  - 524
SP  - 26
EP  - 30
DO  - 10.1016/j.chemphys.2019.05.001
ER  - 

@article{
author = "Milovanović, Branislav and Ilić, Jelica and Stanković, Ivana and Popara, Milana and Petković, Milena and Etinski, Mihajlo",
year = "2019",
abstract = "Understanding the basic chemistry between highly reactive free radicals and dopamine is an important step in characterizing the antioxidative activity of catecholamine neurotransmitters. In this work, we simulated the reactions between dopamine and hydroxyl, peroxyl and methoxy radicals in aqueous solution by employing first principle molecular dynamics based on density functional theory and the BLYP functional. The simulations provide mechanistic insight into the reaction mechanisms but underestimate reaction timescales. The failure of the BLYP functional to address the formal hydrogen atom transfer barriers between dopamine and free radicals is attributed to the self-interaction error.",
publisher = "Elsevier",
journal = "Chemical Physics",
title = "A simulation of free radicals induced oxidation of dopamine in aqueous solution",
volume = "524",
pages = "26-30",
doi = "10.1016/j.chemphys.2019.05.001"
}

Milovanović, B., Ilić, J., Stanković, I., Popara, M., Petković, M.,& Etinski, M.. (2019). A simulation of free radicals induced oxidation of dopamine in aqueous solution. in Chemical Physics
Elsevier., 524, 26-30.
https://doi.org/10.1016/j.chemphys.2019.05.001

Milovanović B, Ilić J, Stanković I, Popara M, Petković M, Etinski M. A simulation of free radicals induced oxidation of dopamine in aqueous solution. in Chemical Physics. 2019;524:26-30.
doi:10.1016/j.chemphys.2019.05.001 .

Milovanović, Branislav, Ilić, Jelica, Stanković, Ivana, Popara, Milana, Petković, Milena, Etinski, Mihajlo, "A simulation of free radicals induced oxidation of dopamine in aqueous solution" in Chemical Physics, 524 (2019):26-30,
https://doi.org/10.1016/j.chemphys.2019.05.001 . .

TY  - JOUR
AU  - Milovanović, Branislav
AU  - Ilić, Jelica
AU  - Stanković, Ivana
AU  - Popara, Milana
AU  - Petković, Milena
AU  - Etinski, Mihajlo
PY  - 2019
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/2950
AB  - Understanding the basic chemistry between highly reactive free radicals and dopamine is an important step in characterizing the antioxidative activity of catecholamine neurotransmitters. In this work, we simulated the reactions between dopamine and hydroxyl, peroxyl and methoxy radicals in aqueous solution by employing first principle molecular dynamics based on density functional theory and the BLYP functional. The simulations provide mechanistic insight into the reaction mechanisms but underestimate reaction timescales. The failure of the BLYP functional to address the formal hydrogen atom transfer barriers between dopamine and free radicals is attributed to the self-interaction error.
PB  - Elsevier
T2  - Chemical Physics
T1  - A simulation of free radicals induced oxidation of dopamine in aqueous solution
VL  - 524
SP  - 26
EP  - 30
DO  - 10.1016/j.chemphys.2019.05.001
ER  - 

@article{
author = "Milovanović, Branislav and Ilić, Jelica and Stanković, Ivana and Popara, Milana and Petković, Milena and Etinski, Mihajlo",
year = "2019",
abstract = "Understanding the basic chemistry between highly reactive free radicals and dopamine is an important step in characterizing the antioxidative activity of catecholamine neurotransmitters. In this work, we simulated the reactions between dopamine and hydroxyl, peroxyl and methoxy radicals in aqueous solution by employing first principle molecular dynamics based on density functional theory and the BLYP functional. The simulations provide mechanistic insight into the reaction mechanisms but underestimate reaction timescales. The failure of the BLYP functional to address the formal hydrogen atom transfer barriers between dopamine and free radicals is attributed to the self-interaction error.",
publisher = "Elsevier",
journal = "Chemical Physics",
title = "A simulation of free radicals induced oxidation of dopamine in aqueous solution",
volume = "524",
pages = "26-30",
doi = "10.1016/j.chemphys.2019.05.001"
}

Milovanović, B., Ilić, J., Stanković, I., Popara, M., Petković, M.,& Etinski, M.. (2019). A simulation of free radicals induced oxidation of dopamine in aqueous solution. in Chemical Physics
Elsevier., 524, 26-30.
https://doi.org/10.1016/j.chemphys.2019.05.001

Milovanović B, Ilić J, Stanković I, Popara M, Petković M, Etinski M. A simulation of free radicals induced oxidation of dopamine in aqueous solution. in Chemical Physics. 2019;524:26-30.
doi:10.1016/j.chemphys.2019.05.001 .

Milovanović, Branislav, Ilić, Jelica, Stanković, Ivana, Popara, Milana, Petković, Milena, Etinski, Mihajlo, "A simulation of free radicals induced oxidation of dopamine in aqueous solution" in Chemical Physics, 524 (2019):26-30,
https://doi.org/10.1016/j.chemphys.2019.05.001 . .

TY  - JOUR
AU  - Milovanović, Branislav
AU  - Stanković, Ivana
AU  - Petković, Milena
AU  - Etinski, Mihajlo
PY  - 2019
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/3318
AB  - The dynamic aspect of solvation plays a crucial role in determining properties of strong intramolecular hydrogen bonds since solvent fluctuations modify instantaneous hydrogen‐bonded proton transfer barriers. Previous studies pointed out that solvent‐solute interactions in the first solvation shell govern the position of the proton but the ability of the electric field due to other solvent molecules to localize the proton remains an important issue. In this work, we examine the structure of the O−H⋅⋅⋅O intramolecular hydrogen bond of dibenzoylmethane in methanol solution by employing density functional theory‐based molecular dynamics and quantum chemical calculations. Our computations showed that homogeneous electric fields with intensities corresponding to those found in polar solvents are able to considerably alter the proton transfer barrier height in the gas phase. In methanol solution, the proton position is correlated with the difference in electrostatic potentials on the oxygen atoms of dibenzoylmethane even when dibenzoylmethane‐methanol hydrogen bonding is lacking. On a timescale of our simulation, the hydrogen bonding and solvent electrostatics tend to localize the proton on different oxygen atoms. These findings provide an insight into the importance of the solvent electric field on the structure of a strong intramolecular hydrogen bond
PB  - Wienheim : Wiley-VCH Verlag GMBH
T2  - ChemPhysChem
T1  - Elucidating Solvent Effects on Strong Intramolecular Hydrogen Bond: DFT-MD Study of Dibenzoylmethane in Methanol Solution
VL  - 20
IS  - 21
SP  - 2852
EP  - 2859
DO  - 10.1002/cphc.201900704
ER  - 

@article{
author = "Milovanović, Branislav and Stanković, Ivana and Petković, Milena and Etinski, Mihajlo",
year = "2019",
abstract = "The dynamic aspect of solvation plays a crucial role in determining properties of strong intramolecular hydrogen bonds since solvent fluctuations modify instantaneous hydrogen‐bonded proton transfer barriers. Previous studies pointed out that solvent‐solute interactions in the first solvation shell govern the position of the proton but the ability of the electric field due to other solvent molecules to localize the proton remains an important issue. In this work, we examine the structure of the O−H⋅⋅⋅O intramolecular hydrogen bond of dibenzoylmethane in methanol solution by employing density functional theory‐based molecular dynamics and quantum chemical calculations. Our computations showed that homogeneous electric fields with intensities corresponding to those found in polar solvents are able to considerably alter the proton transfer barrier height in the gas phase. In methanol solution, the proton position is correlated with the difference in electrostatic potentials on the oxygen atoms of dibenzoylmethane even when dibenzoylmethane‐methanol hydrogen bonding is lacking. On a timescale of our simulation, the hydrogen bonding and solvent electrostatics tend to localize the proton on different oxygen atoms. These findings provide an insight into the importance of the solvent electric field on the structure of a strong intramolecular hydrogen bond",
publisher = "Wienheim : Wiley-VCH Verlag GMBH",
journal = "ChemPhysChem",
title = "Elucidating Solvent Effects on Strong Intramolecular Hydrogen Bond: DFT-MD Study of Dibenzoylmethane in Methanol Solution",
volume = "20",
number = "21",
pages = "2852-2859",
doi = "10.1002/cphc.201900704"
}

Milovanović, B., Stanković, I., Petković, M.,& Etinski, M.. (2019). Elucidating Solvent Effects on Strong Intramolecular Hydrogen Bond: DFT-MD Study of Dibenzoylmethane in Methanol Solution. in ChemPhysChem
Wienheim : Wiley-VCH Verlag GMBH., 20(21), 2852-2859.
https://doi.org/10.1002/cphc.201900704

Milovanović B, Stanković I, Petković M, Etinski M. Elucidating Solvent Effects on Strong Intramolecular Hydrogen Bond: DFT-MD Study of Dibenzoylmethane in Methanol Solution. in ChemPhysChem. 2019;20(21):2852-2859.
doi:10.1002/cphc.201900704 .

Milovanović, Branislav, Stanković, Ivana, Petković, Milena, Etinski, Mihajlo, "Elucidating Solvent Effects on Strong Intramolecular Hydrogen Bond: DFT-MD Study of Dibenzoylmethane in Methanol Solution" in ChemPhysChem, 20, no. 21 (2019):2852-2859,
https://doi.org/10.1002/cphc.201900704 . .