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"Complex compounds"
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The Crystal Structure of a Catena-Triglycinium-µ-Chlorido-Tetrachloridocuprate(II) Glycine Co-crystal
A new complex compound, catena-triglycinium-µ-chlorido-tetrachloridocuprate(II) glycine co-crystal (or glycine-triglycinium pentachlorocuprate), {(C
2
H
6
NO
2
)
3
CuCl
5
·(C
2
H
5
NO
2
)}
n
, was synthesized and studied by single crystal X-ray diffraction (SC XRD) and mid-range infrared spectroscopy. The compound crystallizes in a non-centrosymmetric triclinic
P
1 space group with lattice parameters
a
= 5.1277(2) Å,
b
= 9.1412(6) Å,
c
= 12.2023(5) Å,
α
= 101.407(4)°,
β
= 97.460(3)°,
γ
= 105.832(4)°, Z = 1. The unit cell contains four glycine ions—three glycinium cations and single zwitter-ion—linked through hydrogen bonds network. The anionic part of the compound is presented by infinite chains [CuCl
6
]
n
of distorted (elongated) octahedra, connected by vertices and alternating direction of elongated axis. Positions of hydrogen atoms were refined using geometry optimization via density functional theory (DFT) approach. Thermogravimetric analysis (TGA) showed the title compound to be stable in air atmosphere up to ∼ 388‒393 K and decomposes upon further heating.
Graphical Abstract
Unit cell content of the glycine-triglycinium pentachlorocuprate, determined by the SC XRD analysis
Journal Article
Métodos quelométricos y otros métodos volumétricos de análisis clínicos
Se recopilan en este libro todos los métodos quelométricos que pueden ser usados en Análisis clínicos, con lo cual se pone de relieve la gran ventaja de estas técnicas y se puede contribuir a que la Quelometría encuentre en Química clínica el empleo y atención que merece.
eBook
Investigation of the Effect of a New Type of Copper–Sucrose Complex Compound on the Yield and Quality Parameters of Winter Wheat (Triticum aestivum L.)
We conducted experiments on winter wheat grown in copper-deficient soil, where soil tests revealed a more pronounced deficiency in the deeper layers. As climate change reduces precipitation, plants increasingly rely on nutrients from these deeper layers. A copper–sucrose complex—previously unused in agriculture—was applied as a foliar spray during the tillering and flowering stages. Across the three-year average, significant increases were observed starting from the 1 kg ha−1 copper dose in yield, from 0.3 kg ha−1 in crude protein content, and from 0.5 kg ha−1 in wet gluten content compared to the untreated control. For all three parameters, the highest values were achieved with the 2 kg ha−1 dose. Yield increased by 1.03 t ha−1, crude protein by 0.9%, and wet gluten by 2.3% relative to the control. In 2019, high humidity and favorable temperatures during flowering led to fungal infections in control plots, with DON toxin concentrations exceeding the regulatory safety threshold. Following copper–sucrose complex application, DON levels dropped below this threshold, demonstrating a measurable protective effect.
Journal Article
Spin-Orbit Interactions in Osmium Complexes
Osmium compounds with the Os 5
d
4
electron configuration and an octahedral environment of neighboring atoms attract much attention due to the influence of the spin-orbit interaction on the appearance of magnetic properties in materials. X-ray absorption near edge structure (XANES) spectroscopy makes it possible to obtain information about the value of the spin–orbit interaction from measuring the intensity ratio of lines near the absorption edges. The influence of the spin–orbit interaction on the Os
L
2,3
-edge XANES spectra of osmium compounds having an octahedral environment of halogen atoms is studied. Two types of systems are investigated, namely, isolated osmium clusters in complex compounds and the OsCl
4
compound containing Os polymer chains bridged by Cl atoms. Magnetic-susceptibility measurements show a nonmagnetic ground state and Van Vleck paramagnetism in the case of isolated clusters and a nonzero magnetic moment over the entire temperature range in OsCl
4
. As a result of measurements of the XANES spectra, high values of the line intensity ratio are obtained near the Os
L
3
/
L
2
absorption edges, which is associated with the strong effect of the spin-orbit interaction on the electronic structure. The theoretical analysis of the XANES spectra of Os compounds with different ligands and outer-sphere cations shows that the electronic structure and magnetic properties depend on the spin–orbit interaction, the crystal-field splitting, the electron-pairing energy, and noncubic distortions of the Os environment.
Journal Article
CO2 Hydrogenation over Fe-Co Bimetallic Catalyst Derived from the Thermolysis of Co(NH3)6Fe(CN)6
Reducing the amount of CO2 in the atmosphere is a very important task. Therefore, the development and search for new approaches to the synthesis of catalytic systems, allowing for the catalytic conversion of CO2 into valuable products, is an urgent task. In this work, the catalyst was obtained by the thermolysis of a double complex compound. In this regard, kinetic studies of the parameters of the thermolysis process of double complex salts-[Co(NH)3]6][Fe(CN)6] were additionally determined using isoconversion and model approaches of non-isothermal kinetics. The catalyst was studied using various physicochemical methods—X-ray diffraction (XRD), infrared (IR)-spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). It was shown that, at the stage of catalyst preparation, the formation of a CoFe alloy occurred, while the surface mainly consisted of carbon in sp2-hybridization, and the metals existed in the form of spinel CoFe2O4. It was shown that catalysts based on bimetallic salts were active in the process of hydrogenation of carbon dioxide without a pre-activation stage (CO2 conversion reached 28%, with a specific activity of 4.0 µmolCO2/gMe·s). It was established that it was possible to change the selectivity of the carbon dioxide hydrogenation process by pre-treating the catalyst with hydrogen (selectivity for methane formation in the presence of an unreduced catalyst is 46.4–68.0%, whereas in the presence of a reduced catalyst it is 5.1–16.5%).
Journal Article
Features of the Preparation and Luminescence of Langmuir-Blodgett Films Based on the Tb(III) Complex with 3-Methyl-1-phenyl-4-stearoylpyrazol-5-one and 2,2′-Bipyridine
In this study, we investigated the effect of terbium ions (Tb3+) on the subphases of the limiting area of the molecule for the complex compound (CC) TbL3∙bipy (where HL is 3-methyl-1-phenyl-4-stearoylpyrazol-5-one and bipy is 2,2′-bipyridine). We examined the Langmuir monolayer and the change in the luminescence properties of TbL3∙bipy-based Langmuir-Blodgett films (LBFs). The analysis of the compression isotherms, infrared, and luminescence spectra of TbL3∙bipy LBFs was performed by varying the concentration of Tb3+ in the subphases. Our results demonstrate the partial dissociation of the CC at concentrations of C(Tb3+) < 5 × 10−4 M.
Journal Article
Hexagonal Nanocrystal Growth of Mg or Zn from Incorporation in GaN Powders Obtained through Pyrolysis of a Viscous Complex Compound and Its Nitridation
Hexagonal nanocrystals were obtained from Zn-doped GaN powders and Mg-doped GaN powders, which were synthesized via pyrolysis of a viscous complex compound, followed by its nitridation. XRD showed well-defined peaks for hexagonal GaN with an average crystal size of 21.3 nm. Scanning electron microscopy showed an amorphous and porous appearance in surface morphology, which could be related to the combustion process. Energy-dispersive spectroscopy characterization showed contributions of gallium, nitrogen, and small traces of Zn and Mg in the GaN samples. TEM showed the presence of well-defined hexagonal nanocrystals with an area of 75.9 nm2 for the Zn-doped GaN powders and an area of 67.7 nm2 for the Mg-doped GaN powders. The photoluminescence spectra showed an emission energy of 2.8 eV (431.5 nm) for the Zn-doped GaN powders, while the Mg-doped GaN powders showed energies in the range from 2.7 eV to 2.8 eV (460.3 nm–443.9 nm). The Raman scattering showed spectra where the vibration modes A1(TO), E1(TO), and E2(High) could be observed, which are characteristic of hexagonal GaN.
Journal Article
Mechanisms and implications of bacterial–fungal competition for soil resources
Elucidating complex interactions between bacteria and fungi that determine microbial community structure, composition, and functions in soil, as well as regulate carbon (C) and nutrient fluxes, is crucial to understand biogeochemical cycles. Among the various interactions, competition for resources is the main factor determining the adaptation and niche differentiation between these two big microbial groups in soil. This is because C and energy limitations for microbial growth are a rule rather than an exception. Here, we review the C and energy demands of bacteria and fungi—the two major kingdoms in soil—the mechanisms of their competition for these and other resources, leading to niche differentiation, and the global change impacts on this competition. The normalized microbial utilization preference showed that bacteria are 1.4–5 times more efficient in the uptake of simple organic compounds as substrates, whereas fungi are 1.1–4.1 times more effective in utilizing complex compounds. Accordingly, bacteria strongly outcompete fungi for simple substrates, while fungi take advantage of complex compounds. Bacteria also compete with fungi for the products released during the degradation of complex substrates. Based on these specifics, we differentiated spatial, temporal, and chemical niches for these two groups in soil. The competition will increase under the main five global changes including elevated CO2, N deposition, soil acidification, global warming, and drought. Elevated CO2, N deposition, and warming increase bacterial dominance, whereas soil acidification and drought increase fungal competitiveness.
Journal Article
Introduction to coordination chemistry
\"\"Recommended. Lower-and upper-division undergraduates, two-year technical program students, and general readers.\" (Choice, 1 March 2011) \"Overall then, I applaud this attempt to produce a slightly different and distinctive introduction to a major area of modern chemistry.\" (Reviews, December 2010).
eBook