TY  - JOUR
AU  - Milanović, Ziko
AU  - Dimic, Dusan
AU  - Žižić, Milan
AU  - Milenković, Dejan
AU  - Marković, Zoran
AU  - Avdović, Edina
PY  - 2021
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1504
AB  - Coumarin derivatives have proven beneficial biological activities, but the mechanism of their radical scavenging potency is not fully understood. In this study, the antiradical capacity of two newly synthesized 4,7-dihydroxycoumarin derivatives: (E)-3-(1-((3-hydroxy-4-methoxyphenyl)amino)-ethylidene)-2,4-dioxochroman-7-yl acetate (A-3OH) and (E)-3-(1-((4-hydroxy-3-methoxyphenyl)amino)ethylidene)-2,4-dioxochroman-7-yl acetate (A-4OH) towards HO center dot were examined by Electron Paramagnetic Resonance (EPR) Spectroscopy and Density Functional Theory (DFT). The compounds were fully characterized by the elemental microanalysis, IR, and NMR spectroscopies. The effect of pH on the acid-base equilibria is separately discussed and the predominant species at the physiological pH were determined. Several common mechanisms (Hydrogen Atom Transfer (HAT), Single-Electron Transfer followed by Proton Transfer (SET-PT), Sequential Proton Loss followed by Electron Transfer (SPLET), Radical Adduct Formation (RAF), and Intramolecular Hydrogen Atom Abstraction (iHAA)) of radical scavenging were investigated based on thermodynamic and kinetic parameters. EPR results indicated that both compounds significantly reduce the amount of present HO center dot. The results of the kinetic DFT study demonstrated that both compounds predominantly exhibit antiradical capacity through HAT and SPLET mechanisms. The estimated overall rate constants (k(overall)) proved that A-4OH shows better antioxidant capacity than A-3OH which is well-correlated with the results obtained by EPR measurement.
PB  - MDPI, Basel
T2  - International Journal of Molecular Sciences
T1  - Mechanism of Antiradical Activity of Newly Synthesized 4,7-Dihydroxycoumarin Derivatives-Experimental and Kinetic DFT Study
IS  - 24
VL  - 22
DO  - 10.3390/ijms222413273
ER  - 

@article{
author = "Milanović, Ziko and Dimic, Dusan and Žižić, Milan and Milenković, Dejan and Marković, Zoran and Avdović, Edina",
year = "2021",
abstract = "Coumarin derivatives have proven beneficial biological activities, but the mechanism of their radical scavenging potency is not fully understood. In this study, the antiradical capacity of two newly synthesized 4,7-dihydroxycoumarin derivatives: (E)-3-(1-((3-hydroxy-4-methoxyphenyl)amino)-ethylidene)-2,4-dioxochroman-7-yl acetate (A-3OH) and (E)-3-(1-((4-hydroxy-3-methoxyphenyl)amino)ethylidene)-2,4-dioxochroman-7-yl acetate (A-4OH) towards HO center dot were examined by Electron Paramagnetic Resonance (EPR) Spectroscopy and Density Functional Theory (DFT). The compounds were fully characterized by the elemental microanalysis, IR, and NMR spectroscopies. The effect of pH on the acid-base equilibria is separately discussed and the predominant species at the physiological pH were determined. Several common mechanisms (Hydrogen Atom Transfer (HAT), Single-Electron Transfer followed by Proton Transfer (SET-PT), Sequential Proton Loss followed by Electron Transfer (SPLET), Radical Adduct Formation (RAF), and Intramolecular Hydrogen Atom Abstraction (iHAA)) of radical scavenging were investigated based on thermodynamic and kinetic parameters. EPR results indicated that both compounds significantly reduce the amount of present HO center dot. The results of the kinetic DFT study demonstrated that both compounds predominantly exhibit antiradical capacity through HAT and SPLET mechanisms. The estimated overall rate constants (k(overall)) proved that A-4OH shows better antioxidant capacity than A-3OH which is well-correlated with the results obtained by EPR measurement.",
publisher = "MDPI, Basel",
journal = "International Journal of Molecular Sciences",
title = "Mechanism of Antiradical Activity of Newly Synthesized 4,7-Dihydroxycoumarin Derivatives-Experimental and Kinetic DFT Study",
number = "24",
volume = "22",
doi = "10.3390/ijms222413273"
}

Milanović, Z., Dimic, D., Žižić, M., Milenković, D., Marković, Z.,& Avdović, E.. (2021). Mechanism of Antiradical Activity of Newly Synthesized 4,7-Dihydroxycoumarin Derivatives-Experimental and Kinetic DFT Study. in International Journal of Molecular Sciences
MDPI, Basel., 22(24).
https://doi.org/10.3390/ijms222413273

Milanović Z, Dimic D, Žižić M, Milenković D, Marković Z, Avdović E. Mechanism of Antiradical Activity of Newly Synthesized 4,7-Dihydroxycoumarin Derivatives-Experimental and Kinetic DFT Study. in International Journal of Molecular Sciences. 2021;22(24).
doi:10.3390/ijms222413273 .

Milanović, Ziko, Dimic, Dusan, Žižić, Milan, Milenković, Dejan, Marković, Zoran, Avdović, Edina, "Mechanism of Antiradical Activity of Newly Synthesized 4,7-Dihydroxycoumarin Derivatives-Experimental and Kinetic DFT Study" in International Journal of Molecular Sciences, 22, no. 24 (2021),
https://doi.org/10.3390/ijms222413273 . .

TY  - JOUR
AU  - Erdogan, E.
AU  - Popov, Igor
AU  - Enyashin, Andrey N.
AU  - Seifert, Gotthard
PY  - 2012
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/519
AB  - We report about results from density functional based calculations on structural, electronic and transport properties of one-dimensional MoS2 nanoribbons with different widths and passivation of their edges. The edge passivation influences the electronic and transport properties of the nanoribbons. This holds especially for nanoribbons with zigzag edges. Nearly independent from the passivation the armchair MoS2 nanoribbons are semiconductors and their band gaps exhibit an almost constant value of 0.42 eV. Our results illustrate clearly the edge priority on the electronic properties of MoS2 nanoribbons and indicate problems for doping of MoS2 nanoribbons.
PB  - Springer, New York
T2  - European Physical Journal B
T1  - Transport properties of MoS2 nanoribbons: edge priority
IS  - 1
VL  - 85
DO  - 10.1140/epjb/e2011-20456-7
ER  - 

@article{
author = "Erdogan, E. and Popov, Igor and Enyashin, Andrey N. and Seifert, Gotthard",
year = "2012",
abstract = "We report about results from density functional based calculations on structural, electronic and transport properties of one-dimensional MoS2 nanoribbons with different widths and passivation of their edges. The edge passivation influences the electronic and transport properties of the nanoribbons. This holds especially for nanoribbons with zigzag edges. Nearly independent from the passivation the armchair MoS2 nanoribbons are semiconductors and their band gaps exhibit an almost constant value of 0.42 eV. Our results illustrate clearly the edge priority on the electronic properties of MoS2 nanoribbons and indicate problems for doping of MoS2 nanoribbons.",
publisher = "Springer, New York",
journal = "European Physical Journal B",
title = "Transport properties of MoS2 nanoribbons: edge priority",
number = "1",
volume = "85",
doi = "10.1140/epjb/e2011-20456-7"
}

Erdogan, E., Popov, I., Enyashin, A. N.,& Seifert, G.. (2012). Transport properties of MoS2 nanoribbons: edge priority. in European Physical Journal B
Springer, New York., 85(1).
https://doi.org/10.1140/epjb/e2011-20456-7

Erdogan E, Popov I, Enyashin AN, Seifert G. Transport properties of MoS2 nanoribbons: edge priority. in European Physical Journal B. 2012;85(1).
doi:10.1140/epjb/e2011-20456-7 .

Erdogan, E., Popov, Igor, Enyashin, Andrey N., Seifert, Gotthard, "Transport properties of MoS2 nanoribbons: edge priority" in European Physical Journal B, 85, no. 1 (2012),
https://doi.org/10.1140/epjb/e2011-20456-7 . .

TY  - JOUR
AU  - Erdogan, E.
AU  - Popov, Igor
AU  - Seifert, Gotthard
PY  - 2011
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/498
AB  - We report a systematic research on structural, electronic, and transport properties of a variety of graphene nanoribbon (GNR) break junctions, with different widths and edge chiralities. Our extensive molecular dynamics simulations provide insight into a variety of possible geometries of the break junctions that are obtained by stretching of the graphene ribbons beyond their breaking points. One or more carbon chains can emerge as structural bridges in the junctions. All investigated ruptured systems obey conduction gaps even when their geometries significantly differ by the number of the bridging chains and the variety of their contacts with GNR electrodes.
PB  - Amer Physical Soc, College Pk
T2  - Physical Review B
T1  - Robust electronic and transport properties of graphene break nanojunctions
IS  - 24
VL  - 83
DO  - 10.1103/PhysRevB.83.245417
ER  - 

@article{
author = "Erdogan, E. and Popov, Igor and Seifert, Gotthard",
year = "2011",
abstract = "We report a systematic research on structural, electronic, and transport properties of a variety of graphene nanoribbon (GNR) break junctions, with different widths and edge chiralities. Our extensive molecular dynamics simulations provide insight into a variety of possible geometries of the break junctions that are obtained by stretching of the graphene ribbons beyond their breaking points. One or more carbon chains can emerge as structural bridges in the junctions. All investigated ruptured systems obey conduction gaps even when their geometries significantly differ by the number of the bridging chains and the variety of their contacts with GNR electrodes.",
publisher = "Amer Physical Soc, College Pk",
journal = "Physical Review B",
title = "Robust electronic and transport properties of graphene break nanojunctions",
number = "24",
volume = "83",
doi = "10.1103/PhysRevB.83.245417"
}

Erdogan, E., Popov, I.,& Seifert, G.. (2011). Robust electronic and transport properties of graphene break nanojunctions. in Physical Review B
Amer Physical Soc, College Pk., 83(24).
https://doi.org/10.1103/PhysRevB.83.245417

Erdogan E, Popov I, Seifert G. Robust electronic and transport properties of graphene break nanojunctions. in Physical Review B. 2011;83(24).
doi:10.1103/PhysRevB.83.245417 .

Erdogan, E., Popov, Igor, Seifert, Gotthard, "Robust electronic and transport properties of graphene break nanojunctions" in Physical Review B, 83, no. 24 (2011),
https://doi.org/10.1103/PhysRevB.83.245417 . .

TY  - JOUR
AU  - Erdogan, E.
AU  - Popov, Igor
AU  - Rocha, C. G.
AU  - Cuniberti, G.
AU  - Roche, S.
AU  - Seifert, Gotthard
PY  - 2011
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/492
AB  - The electrical response of graphene-based materials can be tailored under mechanical stress. We report different switching behaviors that take place in mechanically deformed graphene nanoribbons prior to the breakage of the junction. By performing tight-binding molecular dynamics, the study of structural changes of graphene nanoribbons with different widths is achieved, revealing that carbon chains are the ultimate bridges before the junction breaks. The electronic and transport calculations show that binary ON/OFF states can be switched prior to and during breakage depending on the atomic details of the nanoribbon. This work supports the interpretation of recent experiments on nonvolatile memory element engineering based on graphene break junctions.
PB  - Amer Physical Soc, College Pk
T2  - Physical Review B
T1  - Engineering carbon chains from mechanically stretched graphene-based materials
IS  - 4
VL  - 83
DO  - 10.1103/PhysRevB.83.041401
ER  - 

@article{
author = "Erdogan, E. and Popov, Igor and Rocha, C. G. and Cuniberti, G. and Roche, S. and Seifert, Gotthard",
year = "2011",
abstract = "The electrical response of graphene-based materials can be tailored under mechanical stress. We report different switching behaviors that take place in mechanically deformed graphene nanoribbons prior to the breakage of the junction. By performing tight-binding molecular dynamics, the study of structural changes of graphene nanoribbons with different widths is achieved, revealing that carbon chains are the ultimate bridges before the junction breaks. The electronic and transport calculations show that binary ON/OFF states can be switched prior to and during breakage depending on the atomic details of the nanoribbon. This work supports the interpretation of recent experiments on nonvolatile memory element engineering based on graphene break junctions.",
publisher = "Amer Physical Soc, College Pk",
journal = "Physical Review B",
title = "Engineering carbon chains from mechanically stretched graphene-based materials",
number = "4",
volume = "83",
doi = "10.1103/PhysRevB.83.041401"
}

Erdogan, E., Popov, I., Rocha, C. G., Cuniberti, G., Roche, S.,& Seifert, G.. (2011). Engineering carbon chains from mechanically stretched graphene-based materials. in Physical Review B
Amer Physical Soc, College Pk., 83(4).
https://doi.org/10.1103/PhysRevB.83.041401

Erdogan E, Popov I, Rocha CG, Cuniberti G, Roche S, Seifert G. Engineering carbon chains from mechanically stretched graphene-based materials. in Physical Review B. 2011;83(4).
doi:10.1103/PhysRevB.83.041401 .

Erdogan, E., Popov, Igor, Rocha, C. G., Cuniberti, G., Roche, S., Seifert, Gotthard, "Engineering carbon chains from mechanically stretched graphene-based materials" in Physical Review B, 83, no. 4 (2011),
https://doi.org/10.1103/PhysRevB.83.041401 . .