- Institute of Technical Sciences of the Serbian Academy of Sciences and Arts (4)
- University of Belgrade, Faculty of Physical Chemistry (3)
- University of Belgrade, Institute of General and Physical Chemistry (2)
- National Cancer Research Center of Serbia (1)
- Strasbourg University, Hubert Curien Multi-Disciplinary Institute (1)
- Tohoku University, Institute of Multidisciplinary Research for Advanced Materials, Japan (1)
- University of Belgrade, Faculty of Agriculture (1)
- University of Belgrade, Faculty of Technology and Metallurgy (1)
- University of Belgrade, Institute of Chemistry, Technology and Metallurgy (1)
- University of Kragujevac, Faculty of Technical Sciences, Čačak (1)
- Hydrogen storage in a layered flexible [Ni2(btc)(en)2]n coordination polymer (2016)
- [Ni2(btc)(en)2]n coordination polymer exhibits a layered two-dimensional structure with weak interaction between the layers. Correlation of experimental measurements, DFT calculations and molecular simulations demonstrated that its structural features, primarily the inherent flexibility of the layered polymeric structure, lead to improved hydrogen storage performance at room temperature, due to significant enhancement in isosteric heats of hydrogen adsorption. Volumetric measurements of hydrogen adsorption at room temperature show up to 0.3 wt.% hydrogen absorbed at 303 K and 2.63 bar of hydrogen pressure, with isosteric heats of adsorption of about 12.5 kJ mol−1. Predicted performance at room temperature is 1.8 wt.% at 48 bar and 3.5 wt.% at 100 bar, better than both MOF-5 and NU-100, with calculated values of isosteric heats for adsorption of hydrogen in 8–13 kJ mol−1 range at both 77 K and 303 K. Grand canonical Monte Carlo calculations show that this material, at 77 K, exhibits gravimetric hydrogen densities of more than 10 wt.% (up to 8.3 wt.% excess) with the corresponding volumetric density of at least 66 gL−1, which is comparable to MOF-5, but achieved with considerably smaller surface area of about 2500 m2 g−1. This study shows that layered two-dimensional MOFs could be a step towards MOF systems with significantly higher isosteric heats of adsorption, which could provide better room temperature hydrogen storage capabilities.
- Influence of mechanical activation on mechanical properties of PVDF-nanoparticle composites (2016)
- Mechanical activation leads to the creation of new surfaces and decrease in particle size of the initial powder particles, which affects the crystallization of PVDF matrix. In addition, prolonged mechanical activation leads to agglomeration of nanoparticles agglomerates of different sizes. Microstructural changes due to mechanical activation in ZnO, BaTiO3, SrTiO3 and TiO2 powders were investigated using electron microscopy (TEM and SEM), x-ray diffraction (XRD) and particle size analysis (PSA). These were correlated with molecular simulations of mechanical properties of PVDF-nanocluster composites with different oxide nanocluster sizes (1, 1.5 and 2 nm) Each system was simulated using a periodic system of metal oxide nanocrystal inside β-PVDF matrix. β-PVDF was chosen for its superior properties over α- and γ- phases. Geometry of each system was optimized prior to the calculation of mechanical properties using GULP v4.3 software package. Molecular simulations show that, in general, mechanical properties (Young modulus as an indication of elasticity, Shear modulus as an indication of hardness) for all systems improve with decrease in nanocluster size. This suggests that mechanical activation of fillers in PVDF-metal oxide nanoparticle composites should have a positive effect on the mechanical properties of composite systems. This suggests mechanical activation as an easy an inexpensive method of improving mechanical properties of polymer-nanocrystal composite materials.
- Influence of dimensionality on phase transition in VO2 nanocrystals (2013)
- Hydrothermally synthesized one-dimensional and two-dimensional nanocrystals of VO2 undergo phase transition around 65°C, where temperature and mechanism of phase transition are dependent on dimensionality of nanocrystals. Both nanocrystalline samples exhibit depression of phase transition temperature compared to the bulk material, the magnitude of which depends on the dimensionality of the nanocrystal. One-dimensional nanoribbons exhibit lower phase transition temperature and higher values of apparent activation energy than two-dimensional nanosheets. The phase transition exhibits as a complex process with somewhat lower value of enthalpy than the phase transition in the bulk, probably due to higher proportion of surface atoms in the nanocrystals. High values of apparent activation energy indicate that individual steps of the phase transition involve simultaneous movement of large groups of atoms, as expected for single-domain nanocrystalline materials. [Projekat Ministarstva nauke Republike Srbije, br. 142015]
- Ni(II) complex with bishydrazone ligand: synthesis, characterization, DNA binding studies and pro–apoptotic and pro–differentiation induction in human cancerous cell lines (2016)
- A new Ni(II) complex, [Ni(L)(H2O)] (1), with diethyl 3,3'-(2,2'-(1,1'-(pyridine-2,6-diyl)bis(ethan-1-yl-1-ylidene))bis(hydrazin-1-yl-2-ylidene))bis(3-oxopropanoate) ligand (H2L) was synthesized as a potential chemotherapeutic agent. Polidentate ligand was coordinated to Ni(II) NNN-tridentately, in dianionic form, while monodentate water coordination completed square-planar geometry around metal. Structure in the solution was determined by NMR spectroscopy and the same coordination mode was observed in the solid state using IR spectroscopy and further verified by DFT calculations and electrochemical studies. Thermal stability of 1 was determined in both air and nitrogen atmosphere. Anticancer activity of 1 was investigated on acute monocytic leukemia (THP-1) and pancreatic adenocarcinoma (AsPC-1) cell lines. On THP-1 cells 1 induced powerful apoptotic response (ED50 = 10 ± 3 µM), which was revealed to be only partially caspase-dependent, with activation of caspase-8 as the dominant course. This suggested that experimentally validated covalent binding of 1 to DNA is not the only mechanism responsible for programmed cell death. This was supported with experiments on AsPC-1 cells. Although treatment of those cells with 1 resulted in poor apoptotic response, cell cycle changes showed concentration-dependent shifts indicating a dual mechanism of activity. This study also reviews the results of preliminary biological screening, which demonstrates that 1 displays a unique pattern of anticancer activity with at least two mechanisms involved. The authors acknowledge networking support by the COST Action CM1106 StemChem – “Chemical Approaches to Targeting Drug Resistance in Cancer Stem Cells”. The work was funded by the Ministry of Education, Science and Technological Development of the Republic of Serbia (Grant 172055).