TY  - JOUR
AU  - Kovač, Tijana
AU  - Džunuzović, Enis S.
AU  - Džunuzović, Jasna
AU  - Milićević, Bojana
AU  - Sredojević, Dušan
AU  - Brothers, Edward N
AU  - Nedeljković, Jovan M.
PY  - 2018
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/2422
AB  - Surface modification of titanium dioxide nanoparticles (TiO2 NPs) with the biologically active molecule pyridoxine hydrochloride (vitamin B-6) was found to alter the optical properties. Microstructural characterization involving transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis revealed that the anatase TiO2 NPs had a narrow size distribution with an average diameter of 45 angstrom. The absorption onset of the surface-modified TiO2 samples was red-shifted by about 0.4 eV compared to the unmodified particles. The mode of binding between vitamin B-6 and the surface Ti atoms was investigated by Fourier transform infrared spectroscopy (FTIR). From the Benesi-Hildebrand plot, the stability constant of the surface complex was found to be of the order 10(2) M-1. The experimental findings were supported by detailed quantum chemical calculations based on the density functional theory (DFT). Agreement was found between the experimentally measured absorption spectra of the TiO2 NPs surface-modified with vitamin B-6 and the theoretically calculated electronic excitation spectra of the corresponding model system.
AB  - Површинска модификација наночестица титан-диоксида (ТiО2) биолошки активним молекулима пиридоксин-хидрохлорида (витамин B6) доводи до промене њихових оптичких својства. Микроструктурна карактеризација синтетисаних наночестица ТiО2 која обухвата трансмисиону електронску микроскопију (ТЕМ) и дифракцију рендгенских зрака (XRD) показала је да наночестице анатаза имају уску дистрибуцију величина са средњим пречником од 45 Å. Праг апсорпције површински модификованих наночестица ТiО2 је за 0,4 еV померен ка већим таласним дужинама у односу на спектар немодификованих честица. Коришћењем FTIR спектроскопије утврђен је начин везивања
витамина B6 за површинске атоме титана. Константа стабилности површинског комплекса је одређена на основу Бенеси–Хилдебрандове (Benesi–Hildebrand) анализе и износи 3,0×102 М-1. Експериментални резултати су поткрепљени детаљним квантно-хемијским прорачунима заснованим на теорији функционала густине (DFT). Утврђен је висок ниво сагласности између апсорпционог спектра наночестица ТiО2 и теоријски добијеног електронског ексцитационог спектра одговарајућег модела.
PB  - Belgrade : Serbian Chemical Society
T2  - Journal of the Serbian Chemical Society
T1  - Visible light absorption of TiO2 nanoparticles surface-modified with vitamin B-6: A comparative experimental and DFT study
T1  - Апсорпција наночестица TiO2 површински модификованих витамином B6 у видљивом делу спектра: упоредна експериментална и DFT студија
VL  - 83
IS  - 7-8
SP  - 899
EP  - 909
DO  - 10.2298/JSC180131044K
ER  - 

@article{
author = "Kovač, Tijana and Džunuzović, Enis S. and Džunuzović, Jasna and Milićević, Bojana and Sredojević, Dušan and Brothers, Edward N and Nedeljković, Jovan M.",
year = "2018",
abstract = "Surface modification of titanium dioxide nanoparticles (TiO2 NPs) with the biologically active molecule pyridoxine hydrochloride (vitamin B-6) was found to alter the optical properties. Microstructural characterization involving transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis revealed that the anatase TiO2 NPs had a narrow size distribution with an average diameter of 45 angstrom. The absorption onset of the surface-modified TiO2 samples was red-shifted by about 0.4 eV compared to the unmodified particles. The mode of binding between vitamin B-6 and the surface Ti atoms was investigated by Fourier transform infrared spectroscopy (FTIR). From the Benesi-Hildebrand plot, the stability constant of the surface complex was found to be of the order 10(2) M-1. The experimental findings were supported by detailed quantum chemical calculations based on the density functional theory (DFT). Agreement was found between the experimentally measured absorption spectra of the TiO2 NPs surface-modified with vitamin B-6 and the theoretically calculated electronic excitation spectra of the corresponding model system., Површинска модификација наночестица титан-диоксида (ТiО2) биолошки активним молекулима пиридоксин-хидрохлорида (витамин B6) доводи до промене њихових оптичких својства. Микроструктурна карактеризација синтетисаних наночестица ТiО2 која обухвата трансмисиону електронску микроскопију (ТЕМ) и дифракцију рендгенских зрака (XRD) показала је да наночестице анатаза имају уску дистрибуцију величина са средњим пречником од 45 Å. Праг апсорпције површински модификованих наночестица ТiО2 је за 0,4 еV померен ка већим таласним дужинама у односу на спектар немодификованих честица. Коришћењем FTIR спектроскопије утврђен је начин везивања
витамина B6 за површинске атоме титана. Константа стабилности површинског комплекса је одређена на основу Бенеси–Хилдебрандове (Benesi–Hildebrand) анализе и износи 3,0×102 М-1. Експериментални резултати су поткрепљени детаљним квантно-хемијским прорачунима заснованим на теорији функционала густине (DFT). Утврђен је висок ниво сагласности између апсорпционог спектра наночестица ТiО2 и теоријски добијеног електронског ексцитационог спектра одговарајућег модела.",
publisher = "Belgrade : Serbian Chemical Society",
journal = "Journal of the Serbian Chemical Society",
title = "Visible light absorption of TiO2 nanoparticles surface-modified with vitamin B-6: A comparative experimental and DFT study, Апсорпција наночестица TiO2 површински модификованих витамином B6 у видљивом делу спектра: упоредна експериментална и DFT студија",
volume = "83",
number = "7-8",
pages = "899-909",
doi = "10.2298/JSC180131044K"
}

Kovač, T., Džunuzović, E. S., Džunuzović, J., Milićević, B., Sredojević, D., Brothers, E. N.,& Nedeljković, J. M.. (2018). Visible light absorption of TiO2 nanoparticles surface-modified with vitamin B-6: A comparative experimental and DFT study. in Journal of the Serbian Chemical Society
Belgrade : Serbian Chemical Society., 83(7-8), 899-909.
https://doi.org/10.2298/JSC180131044K

Kovač T, Džunuzović ES, Džunuzović J, Milićević B, Sredojević D, Brothers EN, Nedeljković JM. Visible light absorption of TiO2 nanoparticles surface-modified with vitamin B-6: A comparative experimental and DFT study. in Journal of the Serbian Chemical Society. 2018;83(7-8):899-909.
doi:10.2298/JSC180131044K .

Kovač, Tijana, Džunuzović, Enis S., Džunuzović, Jasna, Milićević, Bojana, Sredojević, Dušan, Brothers, Edward N, Nedeljković, Jovan M., "Visible light absorption of TiO2 nanoparticles surface-modified with vitamin B-6: A comparative experimental and DFT study" in Journal of the Serbian Chemical Society, 83, no. 7-8 (2018):899-909,
https://doi.org/10.2298/JSC180131044K . .

TY  - JOUR
AU  - Sredojević, Dušan
AU  - Petrović, Predrag V.
AU  - Janjić, Goran
AU  - Brothers, Edward N
AU  - Hall, Michael B.
AU  - Zarić, Snežana D.
PY  - 2016
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1998
AB  - The strength of the stacking interactions in the bipy complexes of nickel, palladium, and platinum, [M(CN)(2)bipy](2) (M=Ni, Pd, Pt), was calculated using the omega B97xD/def2-TZVP method. The results show that for all considered geometries, interactions are the strongest for platinum, and weakest for nickel complexes, as a result of higher dispersion contributions of platinum over the palladium and nickel complexes. It was also shown that strength of interactions considerably rises with an increase of the stacking overlap area. As a consequence of the favorable electrostatic term, the strength of interactions also rises when metal atom and cyano ligands are involved in the overlap with bipy ligand. The strongest interaction was calculated in the platinum complex, for the geometry that has overlap of metal and cyano ligands with bipy ligand with an energy of -39.80 kcal mol(-1). The energies for similar geometries of palladiumand nickel complexes are -34.60 and -32.45 kcal mol(-1). These energies, remarkably, exceed the strength of the stacking interactions between organic aromatic molecules. These results can be of importance in all systems with stacking interactions, from materials to biomolecules.
PB  - Springer, New York
T2  - Journal of Molecular Modeling
T1  - The stacking interactions of bipyridine complexes: the influence of the metal ion type on the strength of interactions
VL  - 22
IS  - 1
DO  - 10.1007/s00894-015-2888-6
ER  - 

@article{
author = "Sredojević, Dušan and Petrović, Predrag V. and Janjić, Goran and Brothers, Edward N and Hall, Michael B. and Zarić, Snežana D.",
year = "2016",
abstract = "The strength of the stacking interactions in the bipy complexes of nickel, palladium, and platinum, [M(CN)(2)bipy](2) (M=Ni, Pd, Pt), was calculated using the omega B97xD/def2-TZVP method. The results show that for all considered geometries, interactions are the strongest for platinum, and weakest for nickel complexes, as a result of higher dispersion contributions of platinum over the palladium and nickel complexes. It was also shown that strength of interactions considerably rises with an increase of the stacking overlap area. As a consequence of the favorable electrostatic term, the strength of interactions also rises when metal atom and cyano ligands are involved in the overlap with bipy ligand. The strongest interaction was calculated in the platinum complex, for the geometry that has overlap of metal and cyano ligands with bipy ligand with an energy of -39.80 kcal mol(-1). The energies for similar geometries of palladiumand nickel complexes are -34.60 and -32.45 kcal mol(-1). These energies, remarkably, exceed the strength of the stacking interactions between organic aromatic molecules. These results can be of importance in all systems with stacking interactions, from materials to biomolecules.",
publisher = "Springer, New York",
journal = "Journal of Molecular Modeling",
title = "The stacking interactions of bipyridine complexes: the influence of the metal ion type on the strength of interactions",
volume = "22",
number = "1",
doi = "10.1007/s00894-015-2888-6"
}

Sredojević, D., Petrović, P. V., Janjić, G., Brothers, E. N., Hall, M. B.,& Zarić, S. D.. (2016). The stacking interactions of bipyridine complexes: the influence of the metal ion type on the strength of interactions. in Journal of Molecular Modeling
Springer, New York., 22(1).
https://doi.org/10.1007/s00894-015-2888-6

Sredojević D, Petrović PV, Janjić G, Brothers EN, Hall MB, Zarić SD. The stacking interactions of bipyridine complexes: the influence of the metal ion type on the strength of interactions. in Journal of Molecular Modeling. 2016;22(1).
doi:10.1007/s00894-015-2888-6 .

Sredojević, Dušan, Petrović, Predrag V., Janjić, Goran, Brothers, Edward N, Hall, Michael B., Zarić, Snežana D., "The stacking interactions of bipyridine complexes: the influence of the metal ion type on the strength of interactions" in Journal of Molecular Modeling, 22, no. 1 (2016),
https://doi.org/10.1007/s00894-015-2888-6 . .