Monatshefte Fur Chemie最新文献

Honeybees (Apis mellifera) and their products are valuable biomonitors of environmental pollution. This study reports the contents of 48 elements in samples of propolis, bees, pollen, honey, honeycomb, and wax from bee hives in Leoben, Austria. The samples were taken in three campaigns over a period of twelve months. After microwave-assisted acid digestion, the samples were measured with inductively coupled plasma tandem-mass spectrometry (ICP-MS/MS) using nitrous oxide (N₂O) as reaction gas for analytes affected by spectral interferences. Matrix-specific patterns in multielement variations were explored with univariate and multivariate statistical analysis. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) revealed four matrix clusters (propolis; bee; pollen; honey/honeycomb/wax), with element mass fractions generally decreasing in the order propolis > bee > pollen > wax ≈ honeycomb ≈ honey. Two analyte groups could be separated by their PCA loadings, one interpreted as predominantly particle-associated (Li, Al, V, Cr, Fe, Nb, Y, La, Ce, Sm, Eu, Gd, Tb, Dy, Ho, Ta, Sb, Bi, Pb) and the other as more soluble/bioavailable (Na, Mg, Ca, Mn, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Mo, Cd, Ba, Tl). Chondrite-normalized patterns of rare-earth elements including yttrium (REY) showed smooth profiles across all matrices, suggesting geogenic sources and negligible fractionation from biotransformation. Only minor differences were observed between different matrices from the same location. The observed contrasts in REY patterns in honey samples from Austria, Belgium, and Russia support their suitability for tracking regional environmental conditions.

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Supplementary information: The online version contains supplementary material available at 10.1007/s00706-025-03425-2.

This study investigates the wavelength-dependent reactivity of the three germanium-based type I photoinitiators bis(4-methoxybenzoyl)diethylgermane (Ivocerin®), tris(2,4,6-trimethylbenzoyl)ethylgermane, and tetrakis(2-methylbenzoyl)germane. By systematically varying LED wavelengths from 365 to 495 nm, we quantify quantum efficiencies/absorbance and correlate them with the photobleaching behavior and penetration depths. The results highlight the crucial relationship between the emission profile of the light source and the efficiency of the photoinitiators. These insights are particularly relevant for optimizing light-driven processes in applications such as biomedical printing, adhesives, and spatially controlled polymerization.

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Supplementary information: The online version contains supplementary material available at 10.1007/s00706-025-03379-5.

This study describes the first application of an improved procedure on a pencil graphite electrode decorated with functionalized multi-walled carbon nanotubes (f-MWCNTs/PGE) for the determination of the COVID-19 antiviral drug, favipiravir (FVP). The electrochemical behavior of FVP at f-MWCNTs/PGE was examined by cyclic voltammetry and differential pulse voltammetry (DPV) methods, and it was noted that the voltammetric response significantly increased with the modification of f -MWCNTs to the surface. The linear range and limit of detection from DPV studies were determined as 1-1500 µM and 0.27 µM, respectively. In addition, the selectivity of the method was tested toward potential interferences, which can be present in pharmaceutical and biological samples, and it was found that f-MWCNTs/PGE showed high selectivity for the determination of FVP in the presence of probable interferences. The results with high accuracies and precisions from the obtained feasibility studies also revealed that the designed procedure can be used for accurate and selective voltammetric determination of FVP in real samples.

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Molecular docking simulation is a very popular and well-established computational approach and has been extensively used to understand molecular interactions between a natural organic molecule (ideally taken as a receptor) such as an enzyme, protein, DNA, RNA and a natural or synthetic organic/inorganic molecule (considered as a ligand). But the implementation of docking ideas to synthetic organic, inorganic, or hybrid systems is very limited with respect to their use as a receptor despite their huge popularity in different experimental systems. In this context, molecular docking can be an efficient computational tool for understanding the role of intermolecular interactions in hybrid systems that can help in designing materials on mesoscale for different applications. The current review focuses on the implementation of the docking method in organic, inorganic, and hybrid systems along with examples from different case studies. We describe different resources, including databases and tools required in the docking study and applications. The concept of docking techniques, types of docking models, and the role of different intermolecular interactions involved in the docking process to understand the binding mechanisms are explained. Finally, the challenges and limitations of dockings are also discussed in this review.

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The acid-base equilibria of six ACE inhibitors (ACEIs), captopril, cilazapril, enalapril, lisinopril, quinapril, and ramipril, were investigated in the presence of micelles of nonionic surfactant Brij 35. The pK_a values were potentiometrically determined at 25 °C and at a constant ionic strength (0.1 M NaCl). The obtained potentiometric data were evaluated in the computer program Hyperquad. On the basis of the shift in the pK_a values (ΔpK_a) determined in micellar media in relation to the pK_a values previously determined in "pure" water, the effect of Brij 35 micelles on ACEIs ionization was estimated. The presence of nonionic Brij 35 micelles caused a shift in the pK_a values of all ionizable groups of the investigated ACEIs (ΔpK_a from - 3.44 to + 1.9) while shifting the protolytic equilibria of both acidic and basic groups toward the molecular form. The Brij 35 micelles expressed the most pronounced effect on the ionization of captopril among the investigated ACEIs and stronger effect on the ionization of amino than on the ionization of carboxyl groups. The obtained results suggest that ionizable functional groups of ACEIs are involved in interactions with palisade layer of nonionic Brij 35 micelles, which potentially can be considered in physiological conditions. Distribution diagrams of the investigated ACEIs equilibrium forms as a function of pH indicate that the change in distribution is most strongly expressed in pH range 4-8, which includes biopharmaceutically important pH values.

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The synthesis, characterization, and reactivity of several new Cr(II) and Cr(III) complexes featuring an NCN pincer ligand with an arene backbone connected to amine donors NEt₂ and NiPr₂ via CH₂-linkers is described. Reacting the in situ lithiated ligand precursor N(C-Br)N^CH2-Et with [CrCl₃(THF)₃] resulted in the formation of the Cr(III) complex trans-[Cr(κ³NCN-NCN^CH2-Et)(Cl)₂(THF)]. Upon reaction of lithiated N(C-Br)N^CH2-iPr with a suspension of anhydrous CrCl₂, the Cr(II) complex [Cr(κ²NC-NCN^CH2-iPr)₂] is formed featuring two NCN ligands bound in κ²NC-fashion. In contrast, when lithiated N(C-Br)N^CH2-iPr is reacted with a homogeneous solution of anhydrous CrX₂ (X = Cl, Br), complexes [Cr(κ³NCN-NCN^CH2-iPr)X] are obtained. Treatment of [Cr(κ³NCN-NCN^CH2-iPr)Cl] with 1 equiv of PhCH₂MgCl and LiCH₂SiMe₃ afforded the alkyl complexes [Cr(κ³NCN-NCN^CH2-iPr)(CH₂Ph)] and [Cr(κ³NCN-NCN^CH2-iPr)(CH₂SiMe₃)]. All Cr(II) complexes exhibit effective magnetic moments in the range of 4.7-4.9 µ_B which is indicative for d⁴ high spin systems. If a solution of lithiated N(C-Br)N^CH2-iPr is treated with CrCl₂, followed by addition of an excess of Na[HB(Et)₃], the dimeric complex [Cr(κ²NC-NCN^CH2-iPr)(μ₂-H)]₂ is obtained bearing two bridging hydride ligands. [Cr(κ³NCN-NCN^CH2-iPr)(CH₂SiMe₃)] turned out to be catalytically active for the hydrosilylation of ketones at room temperature with a catalyst loading of 1 mol%. X-ray structures of all complexes are presented.

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Supplementary information: The online version contains supplementary material available at 10.1007/s00706-023-03128-6.

The spatial organization of metal oxide nanoparticles represents an important factor in the chemical utilization of resulting structures. For the production of networks that are composed of metal oxide nanoparticle chains, we dispersed vapor phase-grown TiO₂ and ZnO nanoparticles homogeneously in an aqueous polyvinyl alcohol solution. After electrospinning, we analyzed the sizes and diameters of the compositionally homogeneous electrospun fibers and discussed the size distribution and morphology of the nanoparticles inside. Calcination-induced polymer removal gives rise to self-supported nanoparticle-based nanofibers. Particle coarsening by a factor of ~ 2 for TiO₂ and ~ 3 for ZnO nanoparticles is observed.

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Herein, we present a new route to synthesize poly(2-oxazoline)s (POx) with coumarin moieties as pendant groups that can be crosslinked by irradiation to form hydrogels. The synthesis of a novel coumarin-containing 2-oxazoline monomer, 2-[(4-methyl-7-coumarinyloxy)methyl]oxazoline is described in four steps and further its subsequent homo- and copolymerization with 2-ethyl-2-oxazoline (EtOx) via cationic ring-opening polymerization (CROP). The received polymers with different coumarin content (8, 4 and 2 mol%) were compared with a known copolymer synthesized via postpolymerization modification of partially hydrolyzed poly(2-ethyl-2-oxazoline) (PEtOx) with a coumarin derivative. The thermoresponsive behavior of the POx in aqueous solutions was investigated, showing a clear difference in the cloud point temperature (T _cp ) between the polymers synthesized via different strategies. The hydrogel formation was achieved by irradiation with UV light by the following two methods: on the one hand with the pure coumarin-containing POx and on the other hand mixed with poly(ethylene glycol) diacrylate (PEGDA). The obtained hydrogels were compared regarding their swelling degree and their gel content, whereas the swelling degree in water of prepared hydrogels can be tuned by using POx by varying the coumarin content.

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Supplementary information: The online version contains supplementary material available at 10.1007/s00706-022-03013-8.

Treatment of [Co₂(CO)₈] with the ipso-substituted P(C-X)P^Y ligands (X = Br, Cl; R = iPr, tBu) bearing Y = NH and CH₂ linkers under solvothermal conditions affords the five-coordinate Co(I) and Co(III) complexes [Co^I(PCP^Y-R)(CO)₂] and [Co^III(PCP^Y-R)X₂]. The later are paramagnetic exhibiting a solution magnetic moment in the range of 3.0-3.3 μ_B which is consistent with a d⁶ intermediate spin system corresponding to two unpaired electrons. In the case of P(C-X)P^Y ligands (X = Br, Cl; R = tBu; Y = NH) the formation of the square planar Co(II) complex [Co(PCP^NH-tBu)X] was favored. This complex gives rise to a magnetic moment of 1.8 μ_B being consistent with a d⁷ low spin system corresponding to one unpaired electron. All complexes are characterized by means of spectroscopic techniques (NMR, IR), HR-MS. Representative complexes were also characterized by X-ray crystallography.

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Supplementary information: The online version contains supplementary material available at 10.1007/s00706-023-03123-x.