Faculty of Science, Kragujevac

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The Faculty of Science in Kragujevac is constantly evolving and is one of the leading members of the University of Kragujevac. Based on the results of scientific research and pedagogical work of its professors and staff, it is highly ranked among the leading universities in Serbia, with a dedicated and strong international cooperation. The state of Serbia and its Ministry of Education and Science provide great support and assistance to the development of the Faculty of Science and the entire University.

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1-Ferrocenyl-3-(2-methylanilino)propan-1-one
(2012) Leka Z.; Novakovic, Sladjana B.; Pejović, Anka; Bogdanovic, Goran A.; Vukicevic R.
In the ferrocene-containing Mannich base, [Fe(C5H 5)(C15H16NO)], the dihedral angle between the mean planes of the benzene ring and the substituted cyclopentadienyl ring is 84.63 (7)°. The conformation of the title compound significantly differs from those found in corresponding m-tolylamino and p-tolylamino derivatives. In the crystal, C - H⋯O interactions connect the molecules into chains, which further interact by means of C - H⋯π interactions. It is noteworthy that the amino H atom is shielded and is not involved in hydrogen bonding. © 2012 International Union of Crystallography.
1-Ferrocenyl-3-(3-fluoroanilino)propan-1-one
(2012) Leka Z.; Novakovic, Sladjana B.; Pejović, Anka; Bogdanovic, Goran A.; Vukicevic R.
The title ferrocene derivative, [Fe(C 5H 5)(C 14H 13FNO)], crystallizes in the same space group with similar unit-cell parameters as the derivatives 3-anilino-1-ferrocenylpropan-1- one [Leka et al. (2012). Acta Cryst. E68, m229] and 1-ferrocenyl-3-(4- methylanilino)propan-1-one [Leka et al. (2012). Acta Cryst. E68, m230]. The dihedral angle between the best planes of the benzene ring and the substituted cyclopentadienyl ring is 83.4 (1)°. The presence of the electronegative fluoro substituent in the meta position of the aniline group does not alter the crystal packing compared to the other two derivatives. The molecules are connected into centrosymmetric dimers via N - H⋯O hydrogen bonds. In addition, C - H⋯O and C - H⋯N contacts stabilize the crystal packing.
1-Ferrocenyl-3-(4-methylanilino)propan-1-one
(2012) Leka Z.; Novakovic, Sladjana B.; Stevanović, Dragana; Bogdanovic, Goran A.; Vukicevic R.
In the title ferrocene derivative, [Fe(C 5H 5)(C 15H 16NO)], the dihedral angle between the best planes of the benzene and the substituted cyclo-penta-dienyl ring is 83.4 (1)°. The presence of a methyl substituent in the para position of the aniline group does not alter the crystal packing compared to that of 3-anilino-1-ferrocenylpropan- 1-one [Leka et al. (2012). Acta Cryst. E68, m229]. The molecules are connected into centro-symmetric dimers via N - H⋯O hydrogen bonds. In addition, C - H⋯O and C - H⋯N contacts stabilize the crystal packing.
3-(3-Acetylanilino)-1-ferrocenylpropan-1-one
(2012) Novakovic, Sladjana B.; Stevanović, Dragana; Divjaković V.; Bogdanovic, Goran A.; Vukicevic R.
The title ferrocene-containing Mannich base, [Fe(C5H 5)(C16H16NO2)], crystallizes with two independent molecules (A and B) in the asymmetric unit. Molecules A and B have similar conformations. The dihedral angles between the best planes of the benzene and substituted cyclopentadienyl rings are 88.59 (9) and 84.39 (10)° in A and B, respectively. In the crystal, the independent molecules form centrosymmetric dimers via corresponding N - H⋯O hydrogen bonds. The dimers further arrange via C - H⋯π and C - H⋯O interactions. There are no significant interactions between the A and B molecules. © 2012 International Union of Crystallography.
3-Anilino-1-ferrocenylpropan-1-one
(2012) Leka Z.; Novakovic, Sladjana B.; Stevanović, Dragana; Bogdanovic, Goran A.; Vukicevic R.
In the title ferrocene derivative, [Fe(C 5H 5)(C 14H 14NO)], the dihedral angle between the mean planes of the phenyl ring and the substituted cyclo-penta-dienyl ring is 84.4 (1)°. The molecules are connected into centrosymmetric dimers via N - H⋯O hydrogen bonds. In addition, C - H⋯O and C - H⋯N contacts stabilize the crystal packing.
[3.2.1] and [4.1.1] isomers of Lehn's [2.2.2] Cryptand: Prediction of ion selectivity by quantum chemical calculations XV**
(2021) Ćoćić, Dušan; Manaa A.; Siegl S.; Puchta, Ralph; van Eldik R.
Selective alkaline and earth alkaline metal ion encapsulation by two different Lehn-type cryptands, noted as [3.2.1] and [4.1.1], was predicted and between them compared on the DFT (B3LYP/LANL2DZp) basis set. Since these cryptands are isomers to the well-known [2.2.2] cryptand, the cation encapsulation selectivity of all three cages were compared. The ion selectivity and ability of the host to adjust their structure to successfully accommodate the metal ions, were based on energy and geometric criteria. Different lengths of O-Et-O-bridging arms provide an unsymmetrical cryptand host with great flexibility to accommodate large alkali and alkaline earth metal cations.
4-[(4-Methylphenyl)sulfanyl]butan-2-one
(2013) Novakovic, Sladjana B.; Leka Z.; Stevanović, Dragana; Muškinja, Jovana; Bogdanovic, Goran A.
In the title compound, C11H14OS, all non-H atoms are essentially coplanar, with a mean deviation of 0.023 Å. In the crystal, centrosymmetrically related molecules are weakly connected into dimers by pairs of C - H⋯O interactions. The dimers are further linked along the a axis by weak C - H⋯π and C - H⋯S interactions.
4-[(Dimethylamino)methylene]-2-ferrocenyl-5-oxo-4,5-dihydrofuran-3- carboxaldehyde: Synthesis, spectral characterization and single crystal X-ray analysis
(2014) Ratković, Zoran; Muškinja, Jovana; Novakovic, Sladjana B.; Bogdanovic, Goran A.; Micskei K.; Vukicevic R.
The title compound 4-[(dimethylamino)methylene]-2-ferrocenyl-5-oxo-4,5- dihydrofuran-3-carboxaldehyde was synthesized by reacting 3-ferrocenoylpropionic acid with Vilsmeier reagent. This result is rather unexpected, since 3-aroylpropanoic acids under these conditions usually give the corresponding 2-aryl-4-chloro-3-formylfurans. 3-Ferrocenoylpropanoic acid is not the only 3-aroylpropanoic acid that exhibit an unusual behavior under the same conditions: 3-thenoylpropanoic acid gave 4-[(dimethylamino)-methylene]-2-(2- thienyl)-5-oxo-4,5-dihydrofuran-3-carboxaldehyde and 4-[(dimethylamino) methylene]-2-(2-thienyl-5-formyl)-5-oxo-4,5-dihydrofuran-3-carboxaldehyde, whereas 3-(4-methoxybenzoyl)propanoic acid yielded 4-[(dimethylamino)methylene]- 2-(4-methoxyphenyl)-5-oxo-4,5-dihydrofuran-3-carboxaldehyde and 2-(4-methoxyphenyl)-5-chloro-furan-3,4-dicarboxaldehyde. Single crystal X-ray analysis was successfully performed for 4-[(dimethylamino)methylene]-2- ferrocenyl-5-oxo-4,5-dihydrofuran-3-carboxaldehyde and 4-[(dimethylamino) methylene]-2-(2-thienyl)-5-oxo-4,5-dihydrofuran-3-carboxaldehyde and their structures were compared. © 2014 Elsevier Ltd. All rights reserved.
4-Dichloromethyl-4-methyl-5-(nitromethyl)cyclohex-2-enone
(2013) Novakovic, Sladjana B.; Rodic, Marko; Jaćimović Ž.; Ratković, Zoran; Sukdolak S.
In the title compound, C9H11Cl2NO 3, the six-membered ring adopts a screw-chair conformation. In the crystal, two different C - H⋯O hydrogen bonds involving the same acceptor atom connect the molecules into a chain extending along the c-axis direction.
5G tool for evaluation and comparision of energy efficiency of mobile radio channel using second-order statistics
(2020) Stefanovic, Nenad; Kar A.; Mladenovic, Vladimir
© Published under licence by IOP Publishing Ltd. In order to increase energy efficiency over transmissions channels, common approach for optimization tasks is by means of channel's second-order statistics. Actual channel modeling tools for 5G networks end with channel's first-order statistics, although these metrics are not sufficient when channel conditions are rapidly changing, either in time, frequency or space. In this paper, we establish a tool for evaluation and comparision of energy efficiency of mobile radio channel using its second-order statistics, especially level crossing rate (LCR) and average fade durations (AFD), as they can implicitly pinpoint to transmission configurations that are energy efficient or, as oposit, become a waste of energy. Using both deterministic and stochastic channel modeling, we present results after simulations of Rayleigh channel for narrowband case and further extend it to passband cases, suitable for 5G scenario. We conclude about the energy efficiency of different transmission schemes used by the 5G physical layer observing LCR and AFD values.
A 3-D model of ligand transport in a deforming extracellular space
(2010) Kojić N.; Huang A.; Chung, Euiheon; Ivanović, Miloš; Filipovic, Nenad; Kojić M.; Tschumperlin D.
Cells communicate through shed or secreted ligands that traffic through the interstitium. Force-induced changes in interstitial geometry can initiate mechanotransduction responses through changes in local ligand concentrations. To gain insight into the temporal and spatial evolution of such mechanotransduction responses, we developed a 3-D computational model that couples geometric changes observed in the lateral intercellular space (LIS) of mechanically loaded airway epithelial cells to the diffusion-convection equations that govern ligand transport. By solving the 3-D fluid field under changing boundary geometries, and then coupling the fluid velocities to the ligand transport equations, we calculated the temporal changes in the 3-D ligand concentration field. Our results illustrate the steady-state heterogeneities in ligand distribution that arise from local variations in interstitial geometry, and demonstrate that highly localized changes in ligand concentration can be induced by mechanical loading, depending on both local deformations and ligand convection effects. The occurrence of inhomogeneities at steady state and in response to mechanical loading suggest that local variations in ligand concentration may have important effects on cell-to-cell variations in basal signaling state and localized mechanotransduction responses. © 2010 by the Biophysical Society.
A calibration method for realistic neutron dosimetry in radiobiological experiments assisted by MCNP simulation
(2016) Shahmohammadi Beni M.; Krstic, Dragana; Nikezic, Dragoslav; YU, Kwan Ngok Peter
© 2016 The Author 2016. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology. Many studies on biological effects of neutrons involve dose responses of neutrons, which rely on accurately determined absorbed doses in the irradiated cells or living organisms. Absorbed doses are difficult to measure, and are commonly surrogated with doses measured using separate detectors. The present work describes the determination of doses absorbed in the cell layer underneath a medium column (DA) and the doses absorbed in an ionization chamber (DE) from neutrons through computer simulations using the MCNP-5 code, and the subsequent determination of the conversion coefficients R (= DA/DE). It was found that R in general decreased with increase in the medium thickness, which was due to elastic and inelastic scattering. For 2-MeV neutrons, conspicuous bulges in R values were observed at medium thicknesses of about 500, 1500, 2500 and 4000 μm, and these were attributed to carbon, oxygen and nitrogen nuclei, and were reflections of spikes in neutron interaction cross sections with these nuclei. For 0.1-MeV neutrons, no conspicuous bulges in R were observed (except one at ∼2000 μm that was due to photon interactions), which was explained by the absence of prominent spikes in the interaction cross-sections with these nuclei for neutron energies <0.1 MeV. The ratio R could be increased by ∼50% for small medium thickness if the incident neutron energy was reduced from 2 MeV to 0.1 MeV. As such, the absorbed doses in cells (DA) would vary with the incident neutron energies, even when the absorbed doses shown on the detector were the same.
A camphor based 1,3-diamine Ru(ii) terpyridine complex: Synthesis, characterization, kinetic investigation and DNA binding
(2018) Milutinović, Milan; Bugarčić, Živadin; Wilhelm R.
© 2018 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique. The synthesis and reactivity of a new ruthenium(ii) terpyridine complex with a bidentate enantiopure camphor based diamine ligand is described. Reactivity measurements of the Ru(ii) complex showed a high affinity towards guanosine-5′-monophosphate as a model for DNA bases. Furthermore, the Ru(ii) complex was found to interact with CT-DNA. This suggests the high potential of the newly synthesized ruthenium complex as an antitumor agent.
A case of breakdown of the Kekulé-structure model
(2010) Gutman I.; Markovic, Svetlana; Jeremic B.
For a long time, Kekulé structures have been used to predict and rationalize the stability, geometry, and π-electron properties of polycyclic conjugated molecules, especially hydrocarbons. We now point out an example, demonstrating that the Kekulé-structure model is not generally applicable. Namely, the molecule of dibenzo[cd,mn]indeno[123, gf ]pyrene is perfectly planar and strain-free. Yet, its geometry (determined by means of an unrestricted symmetry-broken UB3LYP/6-311G(d,p) DFT method) is in complete disagreement with what one would expect on the basis of its Kekulé structures. © Taylor & Francis Group, LLC.
A case of breakdown of the Pauling bond order concept
(2014) Radenkovic, Slavko; Gutman, Ivan; Antić, Marija
According to the Pauling bond orders, the lengths of the rung carbon-carbon bonds along the central hexagonal chain in chevron-type benzenoid molecules are monotonically changed. The calculated bond lengths obtained at the B3LYP/6-311G(d,p) level of theory show that this regularity holds only for the first few members of the chevron homologous series. In the case of higher members of the series, the predictions of the Pauling bond orders are false. This indicates that the Pauling bond orders are not generally applicable for the prediction of bond lengths.
A combined technique for computation of energy-effect of cycles in conjugated molecules
(2015) Fatoorehchi H.; Gutman, Ivan; Abolghasemi H.
© 2015, Springer International Publishing Switzerland. A direct method for computation of the energy-effect (ef) of cycles in conjugated molecules is elaborated, based on numerical calculation of the (complex) zeros of certain graph polynomials. Accordingly, the usage of the Coulson integral formula can be avoided, and thus the ef-values can be calculated for arbitrary cycles of arbitrary conjugated systems.
A comparative antimicrobial and toxicological study of gold(III) and silver(i) complexes with aromatic nitrogen-containing heterocycles: Synergistic activity and improved selectivity index of Au(III)/Ag(i) complexes mixture
(2016) Savić, Nada; Milivojević D.; Glišić, Biljana; Ilic-Tomic T.; Veselinović J.; Pavic A.; Vasiljevic B.; Nikodinovic-Runic, Jasmina; Djuran, Miloš
© The Royal Society of Chemistry 2016. Five aromatic nitrogen-containing heterocycles, pyridazine (pydz, 1), pyrimidine (pm, 2), pyrazine (pz, 3), quinoxaline (qx, 4) and phenazine (phz, 5) have been used for the synthesis of gold(iii) and silver(i) complexes. In contrast to the mononuclear Au1-5 complexes all having square-planar geometry, the corresponding Ag1-5 complexes have been found to be polynuclear and of different geometries. Complexes Au1-5 and Ag1-5, along with K[AuCl4], AgNO3 and N-heterocyclic ligands used for their synthesis, were evaluated by in vitro antimicrobial studies against a panel of microbial strains that lead to many skin and soft tissue, respiratory, wound and nosocomial infections. All tested complexes exhibited excellent to good antibacterial activity with minimal inhibitory (MIC) values in the range of 2.5 to 100 μg mL-1 against the investigated strains. The complexes were particularly efficient against pathogenic Pseudomonas aeruginosa (MIC = 2.5-30 μg mL-1) and had a marked ability to disrupt clinically relevant biofilms of strains with high inherent resistance to antibiotics. Moreover, the Au1-4 and Ag1-5 complexes exhibited pronounced ability to competitively intercalate double stranded genomic DNA of P. aeruginosa, which was demonstrated by gel electrophoresis techniques and supported by molecular docking into the DNA major groove. Antiproliferative effect on the normal human lung fibroblast cell line MRC5 has also been evaluated in order to determine therapeutic potential of Au1-5 and Ag1-5 complexes. Since the investigated gold(iii) complexes showed much lower negative effects on the viability of the MRC5 cell line than their silver(i) analogues and slightly lower antimicrobial activity against the investigated strains, the combination approach to improve their pharmacological profiles was applied. Synergistic antimicrobial effect and the selectivity index of 10 were achieved for the selected gold(iii)/silver(i) complexes mixtures, as well as higher P. aeruginosa PAO1 biofilm disruption activity, and improved toxicity profile towards zebrafish embryos, in comparison to the single complexes. To the best of our knowledge, this is the first report on synergistic activity of gold(iii)/silver(i) complexes mixtures and it could have an impact on development of new combination therapy methods for the treatment of multi-resistant bacterial infections.
A comparative study of complex formation in the reactions of gold(III) with Gly-Gly, Gly-l-Ala and Gly-l-His dipeptides
(2010) Glišić, Biljana; Rajković, Snežana; Zivkovic, Marija; Djuran, Miloš
Proton NMR spectroscopy was applied to study the reactions of the dipeptides glycyl-glycine (Gly-Gly) and glycyl-l-alanine (Gly-l-Ala) with hydrogen tetrachloridoaurate(III) (H[AuCl4]). All reactions were performed at pH 2.0 and 3.0 and at 40 °C. The final products in these reactions were [Au(Gly-Gly-κ3NG1,N G2,OG2)Cl] and [Au(Gly-l-Ala- κ3NG,NA,OA)Cl] complexes. Tridentate coordination of the corresponding dipeptides and square-planar geometry of these Au(III) complexes was confirmed by NMR (1H and 13C) spectroscopy. This study showed that at pH < 3.0 the Au(III) ion was able to deprotonate the amide nitrogen atom. However this displacement reaction was very slow and the total concentration of the corresponding Au(III)-peptide complex formed after 5 days was less than 60% for the Gly-l-Ala or 70% for the Gly-Gly dipeptide. The kinetic data of the reactions between the Gly-Gly and Gly-l-Ala dipeptides and [AuCl4]- were compared with those for the histidine-containing Gly-l-His dipeptide. The differences in the reactivity of these three dipeptides with the Au(III) ion are discussed. © 2010 Elsevier Inc.
A Comparative Study of the Two Isomers of Bicalicene
(2018) Đurđević Nikolić, Jelena; Gutman I.
© 2018 Taylor & Francis Group, LLC. Two isomers of bicalicene are possible. The trans-isomer is a stable aromatic compound, known since the 1980s. The cis-isomer has never been experimentally prepared and has so far attracted little attention of theoretical chemists. The properties of cis-bicalicene are now studied theoretically, using the B3LYP/6-311G(d,p) quantum-chemical method. All data obtained (geometric, energetic, as well as those based on harmonic oscillator model of aromaticity and nucleus-independent chemical shift indices of local aromaticity) unequivocally indicate that the “missing” isomer of bicalicene is an unstable antiaromatic species, and that the lack of its existence is no surprise whatsoever.
A comparative study of two different finite difference methods for solving advection–diffusion reaction equation for modeling exponential traveling wave in heat and mass transfer processes
(2021) Savovic, Svetislav; Drljača, Branko; DJORDJEVICH, Alexandar
An unconditionally-positive finite difference (UPFD) and the standard explicit finite difference schemes are compared to the analytical solution of the advection–diffusion reaction equation which describes the exponential traveling wave in heat and mass transfer processes. It is found that although the unconditional positivity of the UPFD scheme, this scheme is less accurate than the standard explicit finite difference scheme. This is because the UPFD scheme contains additional truncation-error terms in the approximations of the first and second derivatives with respect to x, which are evaluated at different moments in time. While these terms tend to zero as the mesh is refined, the UPFD scheme nevertheless remains less accurate than its standard explicit finite difference counterpart. The presented results are important when modeling a heat and mass transfer processes using the investigated advection–diffusion reaction equation. Furthermore, current and future developers of coupled multi-species transport models may draw on the ideas of solutions methods employed in this study to further develop numerical models for various types of coupled multi-species transport problems.

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