KRISTALNE STRUKTURE (2-(PIRIDIN-2-IL)-1H-INDOL- 3-IL)(3,4,5-TRIMETOKSIFENIL)-METANONA (HL) I NJEGOVIH KOMPLEKSA SA Cu(II) I Pd(II)

Novel Cu(II) and Pd(II) complexes with 2-(2’-pyridyl)-indole ligand HL, modified with 3,4,5-trimethoxybenzoyl group, were synthesized with the aim of getting biologically active transition metal complexes. The complexes were synthesized by the reaction of HL with CuCl2·2H2O and [PdCl2(CH3CN)2]. Single crystals of HL and complexes [Cu2L2Cl2(DMSO)2] and [PdL(HL)Cl] were obtained and their structures were determined by X-ray diffraction analysis. Cu(II) complex is a centrosymmetric dimer with squarepyramidal geometry around both metal centers, while Pd(II) complex has square-planar geometry. Molecular structures of HL and complexes are given in Fig. 1. Crystal packings of HL and its Pd(II) and Cu(II) complexes are based on hydrogen bonds and π–π stacking interactions. The main crystallographic data: HL, C23H20N2O4, Mr = 388.41, orthorhombic system, space group Pbca, a = 12.861(5), b = 16.810(5), c = 18.764(5) Å, V = 4057(2) Å3, Z = 8, ρ = 1.272 g cm–3, refinement on F2 (270 parameters) yielded R1 = 0.0681, wR2 = 0.1092, S = 1.040 for all data, and R1 = 0.0458 for 2629 observed reflections with I ≥ 2σ(I). [Cu2L2Cl2(DMSO)2], C25H25ClCuN2O5S, Mr = 564.52, triclinic system, space group P –1, a = 7.7503(4), b = 12.0523(7), c = 13.6355(8) Å, α = 83.347(5), β = 81.711(5), γ = 89.180(4)°, V = 1251.88(12) Å3, Z = 2, ρ = 1.498 g cm– 3, refinement on F2 (338 parameters) yielded R1 = 0.0485, wR2 = 0.0934, S = 1.053 for all data, and R1 = 0.0402 for 3839 for observed reflections with I ≥ 2σ(I). [PdL(HL)Cl], C46H39ClN4O8Pd, Mr = 917.66, monoclinic system, space group P21/n, a = 11.8254(2), b = 14.7137(2), c = 23.3483(4) Å, β = 104.498(2)°, V = 3933.13(11) Å3, Z = 4, ρ = 1.550 g cm–3, refinement on F2 (567 parameters) yielded R1 = 0.0396, wR2 = 0.0818, S = 1.051 for all data, and R1 = 0.0307 for 5884 observed reflections with I ≥ 2σ(I).Novi kompleksi Cu(II) i Pd(II) sa 2-(2’-piridil)-indolskim ligandom HL, modifikovanim dodatkom 3,4,5-trimetoksibenzoil grupe, sintetisani su sa ciljem dobijanja biološki aktivnih kompleksa prelaznih metala. Kompleksi su sintetisani reakcijom HL sa CuCl2·2H2O, odnosno [PdCl2(CH3CN)2]. HL i kompleksi [Cu2L2Cl2(DMSO)2] i [PdL(HL)Cl] su dobijeni u vidu monokristala i njihova struktura je rešena rendgenskom strukturnom analizom. Kompleks Cu(II) je centrosimetrični dimer sa kvadratno-piramidalnim okruženjem oko oba metalna centra, dok je kompleks Pd(II) kvadratno- planarne geometrije. Molekulske strukture liganda HL i kompleksa prikazane su na Slici 1. Kristalno pakovanje HL i njegovih kompleksa je zasnovano na vodoničnim vezama i π–π steking interakcijama. Osnovni kristalografski podaci: HL, C23H20N2O4, Mr = 388,41, ortorombični sistem, prostorna grupa Pbca, a = 12,861(5), b = 16,810(5), c = 18,764(5) Å, V = 4057(2) Å3, Z = 8, ρ = 1,272 g cm–3, utačnjavanje sa F2 (270 parametra) dalo je R1 = 0,0681, wR2 = 0,1092, S = 1,040 za sve podatke i R1 = 0,0458 za 2629 refleksija sa I ≥ 2σ(I). [Cu2L2Cl2(DMSO)2], C25H25ClCuN2O5S, Mr = 564,52, triklinični sistem, prostorna grupa P –1, a = 7,7503(4), b = 12,0523(7), c = 13,6355(8) Å, α = 83,347(5), β = 81,711(5), γ = 89,180(4)°, V = 1251,88(12) Å3, Z = 2, ρ = 1,498 g cm–3, utačnjavanje sa F2 (338 parametra) dalo je R1 = 0,0485, wR2 = 0,0934, S = 1,053 za sve podatke i R1 = 0,0402 za 3839 refleksija sa I ≥ 2σ(I). [PdL(HL)Cl], C46H39ClN4O8Pd, Mr = 917,66, monoklinični sistem, prostorna grupa P21/n, a = 11,8254(2), b = 14,7137(2), c = 23,3483(4) Å, β = 104,498(2)°, V = 3933,13(11) Å3, Z = 4, ρ = 1,550 g cm–3, utačnjavanje sa F2 (567 parametra) dalo je R1 = 0,0396, wR2 = 0,0818, S = 1,051 za sve podatke i R1 = 0,0307 za 5884 refleksija sa I ≥ 2σ(I)

METAL-ORGANSKE UMREŽENE STRUKTURE SREBRA(I) SA POTENCIJALNIM ANTIMIKROBNIM SVOJSTVIMA

Jedan od glavnih svetskih problema u javnom zdravlju predstavlja pojava novih otpornih sojeva mikroba. Stoga je potreba za novim antimikrobnim agesima pravi izazov. Metalorganske umrežene strukture (engl. metal-organic frameworks, MOFs) se mogu smatrati obećavajućim antimikrobnim agensima stoga što njihove neorganske i organske komponente mogu da obezbede platformu za visoku antimikrobnu aktivnost. Tokom proteklih godina, nova jedinjenja srebra, uključujući i nove materijale, su se pokazala kao snažni antimikrobni agensi [1]. Uzimajući ovo u obzir, sintetisana su četiri nova MOF-a srebra(I) sa derivatima tiomorfolina i piperazina (Shema 1) koji su okarakterisani rendgenskom strukturnom analizom. Antimikrobna aktivnost je određena na osam bakterijskih sojeva i tri soja gljivica. Kompleks 4 je pokazao dobru antimikrobnu aktivnost na svim testiranim sojevima mikroorganizama.Resistant microbial strains are continuously emerging which is one of the major worldwide public health concerns. The need for new antimicrobial agents is a real challenge. Metal-organic frameworks (MOFs) can be considered as promising antimicrobial materials because their inorganic and organic components can provide platforms to generate high potent antimicrobial activity. Over recent years, new silver compounds, including new materials, have been proposed as potent antimicrobial agents [1]. Taking this into account, four new silver-based MOFs were synthesized (Scheme 1), using thiomorpholine and piperazine derivatives as ligands, and characterized by X-ray diffraction analysis. The antimicrobial activity was evaluated on eight bacterial and three fungi strains. Complex 4 has good antimicrobial activity on all studied microorganisms

Virulence traits associated with Burkholderia cenocepacia ST856 epidemic strain isolated from cystic fibrosis patients

Background: Burkholderia cenocepacia is considered one of the most problematic cystic fibrosis (CF) pathogens. Colonization prevalence in the Serbian CF population is high and virtually exclusively limited to a single highly transmissible clone of B. cenocepacia ST856 which is positive for both the B. cepacia epidemic strain marker (BCESM) and cable pilin, and is closely related to the epidemic strain CZ1 (ST32). Methods: Biofilm formation for 182 isolates, and adhesion to components of the host extracellular matrix, proteolytic activity, mucoidy and motility of selected ST856 representatives, as well as B. cenocepacia ST858 and ST859, and B. stabilis ST857, novel STs isolated from Serbian CF patients, were investigated in this study. The presence of the cepI, cepR, fliG, llpE, wbiI, and bcscV genes was analyzed. Results: Biofilm-formation ability of analyzed strains was poor under standard laboratory conditions, but changed in stress conditions (cold stress) and conditions that mimic CF milieu (increased CO2). All strains expressed ability to bind to collagen and fibronectin albeit with different intensity. Representatives of ST856 exhibited gelatinase activity. ST858, ST859 and 9/11 of ST856 genotypes were positive for swimming and twitching motility whereas ST857 was non-motile. Mucoidy was demonstrated in all ST856 genotypes, ST857 was semi-mucoid, and ST858 and ST859 were non-mucoid. Molecular analysis for major virulence factors revealed that ST856 and ST857 carried the six analyzed genes, while ST858 and ST859 were negative for the llpE gene. Conclusion: Variations in virulence phenotypes in different genotypes of epidemic B. cenocepacia ST856 clone, in vitro, could be a consequence of diversification driven by pathoadaptation. Diversity of epidemic clone genotypes virulence, could be challenging for accurate diagnosis and treatment, as well as for infection control

Supplementary data for article: Filipović, N. R.; Elshaflu, H.; Grubišić, S.; Jovanović, L. S.; Rodić, M.; Novaković, I.; Malešević, A.; Djordjević, I. S.; Li, H.; Šojić, N.; et al. Co(III) Complexes of (1,3-Selenazol-2-Yl)Hydrazones and Their Sulphur Analogues. Dalton Transactions 2017, 46 (9), 2910–2924. https://doi.org/10.1039/c6dt04785h

Supplementary material for: [https://doi.org/10.1039/c6dt04785h]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2430

CHEMICAL COMPOSITION AND QUORUM SENSING INHIBITION ACTIVITY OF HORSERADISH (ARMORACIA RUSTICANA) ROOT EXTRACTS

During the past decades several quorum sensing inhibitors (QSI) of plant origin have been isolated and chemically characterized. QSI agents of plant origin represent potential alternative or complementary approach to antibiotic treatment of multidrug-resistant bacteria and infections caused by bacterial biofilms. The aim of the current study was to screen QSI activities of horseradish root extracts obtained using different organic solvents and different root processing methods (drying at 40°C, 60°C or extraction of fresh material). Common opportunistic pathogen Pseudomonas aeruginosa MMA83 was used for QSI screen. RT-qPCR was used to analyze the effect of the extract on the relative mRNA levels of the genes QS (lasR, lasI, rhlR, rhlI, mvfR, pqsH) and the genes involved in P. aeruginosa MMA83 virulence (lasB, phzM, rhlC, algK, pvdS). Chemical composition of extracts was determined by UHPLC Q-ToF MS analysis. The most active extract obtained using fresh roots and hexane/ethyl acetate (1:1) solvent mixture was able to significantly reduce content all examined mRNA. Qualitative chemical analysis reviled presence of 15 phenolic acids and their derivatives, 9 flavonoids and 10 glucosinolates in majority of examined extracts. It is significant to emphasize that the most active QSI extract did not contain a single one, out of ten dominant glucosinolates, which have undergone to hydrolysis yielding isothiocyanates and other sulphur-containing compounds responsible for QSI effects. Our results strongly indicate that even mild thermal treatment (40°C) of horseradish roots prior to extraction could lead to severe reduction or loss of QSI activity.Book of abstract: From biotechnology to human and planetary health XIII congress of microbiologists of Serbia with international participation Mikromed regio 5, ums series 24: 4th – 6th april 2024, Mona Plaza hotel, Belgrade, Serbi

CuO-based nanoplatelets for humidity sensing application

Determination and monitoring of humidity level is of great importance because water is one of essential components of the living organisms and materials used by people. Metal oxides are the most popular materials used as sensing elements for humidity sensors, due to their excellent thermal and environmental stability, high mechanical strength, wide range of working temperature, low fabrication cost and robustness in practical applications. Humidity sensing ability of metal oxide based ceramic materials can be enhanced by doping with metal cations. In this work, we present hydrothermal method for preparation of pure and Mgdoped CuO nanoplatelets and investigate their sensing properties towards humidity. The proposed method involves autoclaving of copper(II)-acetate solution under autogenous pressure in alkaline conditions, with different concentrations of Mgdopant (0, 2.5, 5 and 10 mol%). We have performed thorough structural and optical investigations of as synthesized material (TEM, XRD, SAED, UV-VIS-NIR). Furthermore, we have processed obtained powders into functional thick films using doctor blade technique, and their sensing properties were tested in wide range of temperatures (25, 50, 75 °C) and relative humidities (40–90%), resulting with strong response and promising response/recovery times

The influence of spark plasma sintering temperature on the properties of Sb-doped barium stannate ceramics

Barium-stannate (BaSnO3, BSO) is a member of the perovskite-type alkaline earth stannates ASnO3 (A = Ca, Sr, Ba) with an ideal cubic crystal structure (space group: ). Doping with antimony (Sb5+) can change this wide band-gap semiconductor (Eg = 3.1-3.4 eV) into an n-type semiconductor with high electrical conductivity at room temperature. The major drawbacks in the BSO-based ceramics synthesis are phase composition and low density of final ceramic materials. These problems could be solved using spark plasma sintering (SPS), a current and pressure-assisted technique, which enables the preparation of dense ceramics at significantly lower temperatures and for a shorter time. To investigate the influence of spark plasma sintering temperature on the structural, microstructural and electrical properties of BaSn1-xSbxO3 (BSSO, x = 0.00; 0,04; 0.06; 0.08; and 0.10) ceramics samples, BSSO powders were spark plasma sintered at 1100 °C, 1200 °C and 1250 °C for 5 min. X-ray diffraction (XRD) analysis confirmed that all ceramic samples sintered at 1100 °C crystallized in a single-phased cubic BSO structure. Their relative densities were in the range of 72–82% ρt. Sintering at 1200 °C increased the samples’ relative densities to 79–96% ρt, but also induced the formation of a barium-rich secondary phase, Ba2SnO4. Rising the sintering temperature further to 1250 °C induced the melting of all samples except BaSn0.92Sb0.08O3. Field emission scanning electron microscopy (FE-SEM) revealed that doping with antimony decreased the grain sizes in BSSO samples sintered at 1100 °C and 1200 °C up to the concentration x = 0.08. Electrical measurements revealed the typical semiconductor behavior of the undoped samples, showing nonlinear current-voltage characteristic and the existence of one semicircle in their impedance spectra, characteristic for materials with double Schottky barrier at the grain boundaries. However, samples with higher dopant concentrations (x = 0.08 and 0.10) showed significantly lower electrical resistivity and linear current-voltage characteristic. The lowest and almost constant value of electrical resistivity in the temperature range of 25–150 °C, and complete loss of the semicircle in its impedance spectrum revealed the metallic-like behavior of sample BaSn0.92Sb0.08O3 sintered at 1200 °C

Quantum sensors for gas mixture detection

Numerous methods have been utilized for molecular detection, including optical, calorimetric, acoustic, and techniques based on changes in electrical properties, such as metal oxide semiconductor sensors [1,2]. Recent research endeavors have led to a significant rise in sensitivity, detecting parts per billion (ppb) [3], but the challenges of selectivity and cross-sensing remain crucial areas of investigation. Developing a gas sensor with high selectivity to efficiently analyze multi-gas mixtures would be of great significance, with potential applications in various fields such as technology, environmental control, biology, and medicine. Quantum sensors are a promising new technology for the detection of gas mixtures. They offer a number of advantages over traditional methods, including high sensitivity, selectivity, and response time. In the presentation, we propose a new method based on the resonant interaction of dipole molecules with ac fields, in the presence of a dc electric and magnetic field that creates Zeeman and Stark splitting of molecular levels specific to certain molecules, ensuring selectivity [4]. In this talk, we present some preliminary experimental results obtained for the molecule NO on the use of quantum sensors for the detection of gas mixtures. Our results demonstrate the potential of quantum sensors for a variety of applications in gas sensing. We believe that quantum sensors have the potential to revolutionize the field of gas sensing. 1. X. Liu, et al. Sensors (Basel), 12 (2012) 9635–9665. 2. S. Lakkis, R. Younes, Y. Alayli, M. Sawan, Sensor Review, 34 (2014) 24–35. 3. J.-H. Lee, J.-Y. Kim, J.-H. Kim, S. S. Kim, Sensors (Basel), 19 (2019) 726. 4. Z. Branković, Y. Rostovtsev, Sci. Rep., 10 (2020) 1537

Intercropping spring-sown annual legumes with cereals for forage production

Growing annual legumes such as pea (Pisum sativum L.) and vetches (Vicia spp.) in mixtures with cereals is one of the most traditional ways of both forage and grain production in many temperate climates in Europe, Asia Minor and Near and Central East. This practice is considered beneficial kind of intercropping may serve for both forage and grain production. In Serbia and other Balkan countries, intercropping annual legumes with cereals is rather widespread and is extensively used for producing quality and protein-rich forage in feeding dairy cows and other ruminants. In a small-plot trial, carried out during the trials years of 2010, 2011 and 2012, there were included the intercrops of three spring-sown cereals, namely common wheat (Triticum aestivum L. subsp. aestivum), barley (Hordeum vulgare L.) and oat (Avena sativa L.), six spring-sown annual legumes, such as pea, common vetch (V. sativa L.), Narbonne vetch (V. narbonensis L.), faba bean (V.faba L.), grass pea (Lathyrus sativus L.) and white lupin (Lupinus albus L.), and the sole crops of each intercrop component. Each intercrop was sown at a rate of 75%n of a legume and 25% of a cereal in comparison to the sowing rates in their sole crops