1. Mixed-ligand copper(ii) complexes derived from pyridinecarbonitrile precursors : structural features and thermal behaviorAmalija Golobič, Matjaž Kristl, Tinkara Marija Podnar, Zvonko Jagličić, Brina Dojer, 2025, izvirni znanstveni članek Opis: Pyridinecarbonitriles (pyCN), also referred to as cyanopyridines, are promising ligands for the formation of pyridine-based coordination compounds due to their two different N-donor atoms, which enable versatile coordination modes. Copper(II) complexes containing pyCN derivatives are of particular interest for their potential applications in medicinal chemistry and materials science. In this study, the synthesis, structural characterization, and thermal and magnetic properties of three new copper(II) complexes with 3-pyCN, 4-pyCN, and ethyl picolinimidate, obtained in situ by means of alcoholysis of 2-pyCN, are reported: [Cu2(μ-Ac)4(3-pyCN)2] (1), [Cu(H2O)2(Etpic)2]NO3 (2), and [Cu(NO3)2(CH3CN)(4-pyCN)2]·CH3CN (3). Single-crystal X-ray diffraction confirmed that complex 1 features a dinuclear paddle-wheel structure with bridging acetato ligands and monodentate 3-pyCN molecules, coordinated through the ring nitrogen, while complexes 2 and 3 are mononuclear. Thermal analysis showed an intense and highly exothermic decomposition of complex 3, containing nitrate ligands. Magnetic measurements revealed strong antiferromagnetic coupling in the dinuclear complex 1, whereas complexes 2 and 3 displayed paramagnetic behavior with effective magnetic moments ranging from 1.8 μB to 2.0 μB, consistent with isolated Cu(II) centers.
Ključne besede: copper(II) coordination compounds, cyanopyridines, crystal structure, magnetic properties, thermogravimetric analysis
Objavljeno v DKUM: 29.08.2025; Ogledov: 0; Prenosov: 3
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2. Integrated optimization framework for a biomass supply network and steam Rankine cycleMonika Dokl, Zdravko Kravanja, Lidija Čuček, 2024, izvirni znanstveni članek Opis: The optimization of biomass supply chains is becoming increasingly important, especially for low-density biomass feedstocks that have limited market value and require efficient handling and logistics. This study addresses this issue by proposing an integrated approach to optimize biomass supply chain networks for energy production with the steam Rankine cycle. The approach takes into account the inherent variability of feedstock availability and energy market values, to ensure adaptability to fluctuating conditions. The biomass supply network is formulated as a mixed-integer nonlinear programming problem, where the optimization objective is to maximize the economic viability of the system. The optimal configuration of the supply network includes the selection of biomass supply zones and storage facilities, the transportation links, and the optimization of the process variables within the conversion plants, taking into account the variable heat demand. The optimization approach is applied to a hypothetical case study of a relatively small region in Slovenia. The results show the economic viability of biomass utilization with a net present value of almost 300 MEUR, generating about 4 MW of electricity and 65 MW of heat. The uncertainties of the biomass supply, the fluctuations in product prices and the spatial scope of the case study are evaluated in addition. This analysis highlights and discusses the impact of these factors on the economic performance of the biomass supply chain network.
Ključne besede: copper(II) coordination compounds, methylamines, crystal structure, magnetic properties, thermogravimetric analysis
Objavljeno v DKUM: 31.01.2025; Ogledov: 0; Prenosov: 8
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3. Synthesis, crystal structure and magnetic properties of a new hydroxylammonium fluoroferrateBrina Dojer, Matjaž Kristl, Zvonko Jagličić, Amalija Golobič, Marta Kasunič, Mihael Drofenik, 2012, izvirni znanstveni članek Opis: This paper reports on the synthesis of a new hydroxylammonium fluoroferrate, with the formula $(NH_3OH)_3FeF_6$, obtained after dissolving iron powder in hydrofluoric acid and adding solid $NH_3OHF$. This new compound has been characterized by chemical and thermal analysis, single-crystal X-ray diffraction, and magnetic measurements. The title compound crystallizes trigonal, R3c, with cell parameters a = 11.4154(2) Å, c = 11.5720(2) Å, Z = 6. The structure consists of $NH_3OH^+$ cations and isolated $FeF_6^{3–}$ octahedra in which the central ion lies on a threefold axis. The oxygen and nitrogen atoms of the hydroxylammonium cations are donors of hydrogen bonds to fluoride anions, resulting in a network of hydrogen bonds between counterions. The effective magnetic moment $µ_{eff}$ = 5.8 BM was calculated and perfectly matches the expected value of high-spin Fe(III) ions. The thermal decomposition of the compound was studied by TG, DSC, and X-ray powder diffraction.
Ključne besede: inorganic chemistry, crystallography, coordination compounds, synthesis, crystal structure, characterization of compounds, determination of the structure of compounds, X-ray diffraction, magnetic measurements, thermal analysis, TG, DSC, hydrogen bond, metal complexes, hydroxylammonium fluoromethalatehydroxylammonium, fluoroferrate
Objavljeno v DKUM: 25.08.2017; Ogledov: 2076; Prenosov: 76
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4. Synthesis and characterisation of hydroxylammonium fluorochromateMatjaž Kristl, Mihael Drofenik, Ljubo Golič, Amalija Golobič, 2003, izvirni znanstveni članek Opis: Reactions in the system $Cr – NH_3OHF – HF – H_2O$ were investigated. Green crystals of a new compound with the formula $(NH_3OH)_3CrF_6$ have been isolated from the water solution and characterized by chemical analysis. The compound crystallizes as triclinic, P-1, with cell parameters: a = 6.5461(2) Å, b = 6.9347(2) Å, c = 9.4072(3) Å, α = 86.772(1)°, β = 83.804(1)°, γ = 70.283(1)°. The effective magnetic moment, $µ_{eff}$ = 3.82 BM, was calculated from magnetic susceptibility measurements in the temperature range 80-290 K. The thermal decomposition of the compound was studied by TG and DSC analysis. $(NH_3OH)_3CrF_6$ decomposes above 125 °C in three steps and the residue has been identified by X-ray powder diffraction as $α – Cr_2O_3$.
Ključne besede: inorganic chemistry, structural chemistry, crystalline structure, coordination compounds, synthesis, inorganic reactions, thermal decomposition, characterization of compounds, TG, DSC, X-ray diffraction, chromium complexes, hydroxylammonium fluoro chromates, crystals
Objavljeno v DKUM: 25.08.2017; Ogledov: 1893; Prenosov: 118
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5. The crystal and molecular structures of two reaction products of geminal dicyano oxirane with thiohydantoine (compound I) and thioxobenzoxazole (compound II)Ivan Leban, Alenka Majcen Le Marechal, Albert Robert, 1993, izvirni znanstveni članek Opis: The crystal and molecular structures of two reaction products of geminal dicyano oxiranes with thiohydantoione and thioxobenzoxazole have been determinated from ▫$Mo-K_\alpha$▫ X-ray diffraction data. The two reaction products were: 2H-2-(p-tolyl)-imidazol[1,2-b]thiazole-3,6-dione (compound I) and Z-3-benzoxazole-3-phenyl-2-oxo-2-propanenitrile (compound II) with the following crystal data at 293(1) K: Compound I, ▫$C_{12}H_{10}N_2O_2S$▫, monoclinic ▫$P2_1/c$▫, a=15057(3), b=5.200(3), c=14.724(4) Å, ▫$\beta=104.24(3)°$▫, Z=4; final R and ▫$R_w$▫ values were 0.034 and 0.049 for1647 observed reflexions. Compound II, ▫$C_{16}H{10}N_2O_2$▫, monoclinic, ▫$P2_1/n$▫, a=14.396(3), b=4.326(1), c=21.335(4) Å, ▫$\beta-107.79(1)°$▫, Z=4;final R and ▫$R_w$▫ values 0.040 and 0.053 for 1516 observed reflections.
Ključne besede: organic chemistry, crystal structure, chemical reactions, oxiranes, coordination compounds, structural chemistry
Objavljeno v DKUM: 05.07.2017; Ogledov: 1572; Prenosov: 118
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