50 research outputs found

    Synthesis and characterization of some pyrazole derivatives and their reactions with transition metals

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    Reactions of 3,5-dimethylpyrazole-1-carboxamidinium nitrate (dpca∙HNO3) and 4-acetyl-3-amino-5-methylpyrazole (aamp) with transition metals under different reaction conditions are presented. The template reaction of aamp with triethyl orthoformate (teof) in the presence of metal ion is described. Besides, condensation of aamp with thiosemicarbazide (tsc) and the coordination of its product to copper(II) ion is also described. Twelve new complex compounds are synthesized and fully characterized. The characterization of two other, already known complexes is significantly enriched. The influence of HSAB interactions between the metal ions and ligators on the structures of obtained compounds is studied. The influence of the reaction conditions on the composition, structure and quality of crystals obtained in the reactions is investigated. Compounds are characterized by structural analysis, elemental analysis, molar conductivity data, infrared spectrometry and thermal analysis. Some selected complexes are characterized by UV-Vis spectra, magnetic measurements and biological activity tests, too.Reactions of 3,5-dimethylpyrazole-1-carboxamidinium nitrate (dpca∙HNO3) and 4-acetyl-3-amino-5-methylpyrazole (aamp) with transition metals under different reaction conditions are presented. The template reaction of aamp with triethyl orthoformate (teof) in the presence of metal ion is described. Besides, condensation of aamp with thiosemicarbazide (tsc) and the coordination of its product to copper(II) ion is also described. Twelve new complex compounds are synthesized and fully characterized. The characterization of two other, already known complexes is significantly enriched. The influence of HSAB interactions between the metal ions and ligators on the structures of obtained compounds is studied. The influence of the reaction conditions on the composition, structure and quality of crystals obtained in the reactions is investigated. Compounds are characterized by structural analysis, elemental analysis, molar conductivity data, infrared spectrometry and thermal analysis. Some selected complexes are characterized by UV-Vis spectra, magnetic measurements and biological activity tests, to

    Comparison of Self-reported and Observed Road Safety Performance Indicators

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    The first concept of road safety performance indicators was published by European Transport Safety Council, Brussels in 2001. Hungary has long and reliable time series of safety belt wearing and child safety seat usage rates in passenger cars. These rates are based on real roadside observations and representative sample, meeting the requirements of international road accident databases. The methodology of the data collection has been further developed during the recent years, but we paid attention to the possibility of comparison with the earlier data and consistent analysis of time series. Although the roadside observations could not have been organized in each year, the trends can be seen relatively well. Our initial hypothesis was that the self-reported data always show a bit "better" picture about the driving behaviour than the observed ones, since the people are not sure that their data will be handled in an anonym way. Based on these results we can say that the ESRA results are relatively good estimations of the real safety belt wearing rates

    Some Aromatic Schiff Bases and Their Metal Complexes

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    Schiff bases represent a widely studied group of compounds, interesting from the synthetic and structural, but also applicational point of view. Among these, aromatic Schiff bases stand out due to their stability and possible application as safer therapeutic agents. Since the presence of the phenolic group and the heteroatom in the benzene ring seems to be of interest for the biological activity of Schiff bases, imine derivatives of some dihydroxybenzaldehydes, 2-acetylpyridine, and 2,6-diacetylpyridine are chosen to be described here. The syntheses, structural features, as well as investigations of possible application of Schiff bases themselves, but also their metal complexes are described. The Cambridge Structural Database has been searched to obtain a better knowledge of the structures of these Schiff bases and their metal complexes, structural changes upon coordination, and the most common and interesting modes of coordination. The main accent is given to those compounds that are promising candidates for medicinal and pharmaceutical use, but some of the described complexes are good as catalysts, optical materials, sensors, analytical reagents, etc

    Transition metal complexes with thiosemicarbazide-based ligands. Part 60. Reactions of copper(II) bromide with pyridoxal S-methylisothiosemicarbazone (PLITSC). Crystal structure of [Cu(PLITSC−H)H2O]Br•H2O

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    The synthesis and structural characterization of a square-planar copper(II) complex with pyridoxal S-methylisothiosemicarbazone (PLITSC) of the formula [Cu(PLITSC−H)H2O]Br•H2O (1) as the first Cu(II) complex with monoanionic form of this ligand were described. Complex 1 together with two previously synthesized complexes [Cu(PLITSC)Br2] (2) and [Cu(PLITSC)Br(MeOH)]Br (3) were characterized by elemental analysis, IR and electronic spectra and also by the methods of thermal analysis, conductometry and magnetochemistry. [Projekat Pokrajisnkog sekretarijata za nauku i tehnoloski razvoj Vojvodine i Ministarstva nauke Republike Srbije, br. 172014

    1D and 2D Silver-Based Coordination Polymers with Thiomorpholine-4-carbonitrile and Aromatic Polyoxoacids as Coligands: Structure, Photocatalysis, Photoluminescence, and TD-DFT Study

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    Four silver-based coordination polymers, {[Ag(L)2](BF4)}∞ (1), {[Ag(H2BTC)(L)]·(H3BTC)}∞ (2), {[Ag2(H2BTEC)(L)2]·3.33H2O}∞ (3), and [Ag(H25SSA)(L)]∞ (4), were synthesized using thiomorpholine-4-carbonitrile (L) as the primary ligand and three aromatic polyoxoacids as coligands: trimesic (H3BTC), pyromellitic (H4BTEC), and 5-sulfosalicylic acid (H35SSA). Compounds 1 and 3 are two-dimensional, while 2 and 4 are one-dimensional. L acts as a bis-monodentate ligand, while the Ag(I) ion is three-coordinated in 2 and four-coordinated in all of the other compounds. The tetrahedral coordination of Ag(I) in 3 leads to an almost complete absence of intermolecular interactions with the metal center. All compounds show reasonable photocatalytic activity for photocatalytic degradation of mordant blue 9 dye, with reaction rates in the 0.036–0.056 min–1 range. Changes in the reaction rates can be correlated with the type and coordination of the coligand. Complex 3 exhibits photoluminescence at 77 K, while 4 exhibits photoluminescence at both room temperature and 77 K. Luminescence lifetimes indicate electronic transitions of singlet parentage, where transitions are allowed. A TD-DFT study determined the contributions of individual singlet–singlet electronic excitations to the fluorescence, indicating that metal– intraligand transitions are responsible for luminescence in both complexes.This is the peer-reviewed version of the article: Ristić, P., Todorović, T.R., Blagojević, V., Klisurić, O.R., Marjanović, I., Holló, B.B., Vulić, P., Gulea, M., Donnard, M., Monge, M., Rodríguez-Castillo, M., López-de-Luzuriaga, J.M., Filipović, N.R., 2020. 1D and 2D Silver-Based Coordination Polymers with Thiomorpholine-4-carbonitrile and Aromatic Polyoxoacids as Coligands: Structure, Photocatalysis, Photoluminescence, and TD-DFT Study. Crystal Growth & Design 20, 4461–4478. [https://doi.org/10.1021/acs.cgd.0c00287]Supplementary material: [https://hdl.handle.net/21.15107/rcub_dais_9452
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