Search Results (109)

Background: Transition metal complexes incorporating fluorinated counter anions represent a significant class of compounds with broad applications in industry, pharmaceuticals, and biomedicine. These fluorinated anions are known to enhance the solubility, stability, and reactivity of the complexes, thereby expanding their functional utility in various chemical and biological contexts. Methods: A set of metal(II) complexes of the general formula [MPy₆][B(C₆F₅)₄]₂ where (Py = pyridine, M = Mn (1), Fe (2), Co (3), Ni (4), Cu (5), Zn (6)) have been synthesized by direct reaction of metal halides and pyridine in the presence of Ag[B(C₆F₅)₄]. The complexes were characterized using different techniques to assure their purity, such as elemental analysis (EA), electron paramagnetic resonance (EPR) spectroscopy, thermogravimetric analysis (TGA), ultraviolet–visible (UV–Vis) spectroscopy, ¹¹B-NMR, ¹H-NMR, and FT-IR spectroscopy. The antimicrobial and antifungal properties against different types of bacteria and fungi were studied for all prepared complexes. Results: The synthesized complexes exhibited broad-spectrum antimicrobial activity, demonstrating variable efficacy compared to the reference antibiotic, oxytetracycline (positive control). Notably, complex 6 displayed exceptional antibacterial activity against Streptococcus pyogenes, with a minimum inhibitory concentration (MIC) of 4 µg/mL, outperforming the control (MIC = 8 µg/mL). Complexes 1, 2, and 4 showed promising activity against Shigella flexneri, Klebsiella pneumoniae, and Streptococcus pyogenes, each with MIC values of 8 µg/mL. Conversely, the lowest activity (MIC = 512 µg/mL) was observed for complexes 3, 5, and 6 against Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae, respectively. Regarding antifungal properties, complexes 5 and 6 demonstrated the highest activity against Candida albicans, with MIC values of 8 µg/mL, equivalent to that of the positive control, fluconazole. Density functional theory (DFT) calculations confirmed an overall octahedral coordination geometry for all complexes, with tetragonal distortions identified in complexes 3, 4, and 5. Full article

We studied the adsorption thermodynamics and mechanism behind the binding of nitric oxide (NO) in the interior surfaces and structural fragments of the high metal center density microporous Metal-Organic Framework (MOF) CPO-27-Cu, by gas sorption, at a series of temperatures. For the purpose of comparison, we also measured the corresponding CO₂ adsorption isotherms, and as a result, the isosteric heats of adsorption for the two studied adsorptives were derived, being in the range of 12–15 kJ/mol for NO at loadings up to 0.5 NO molecules per formula unit (f.u.) of the bare compound (C₄O₃HCu), and 23–25 kJ/mol CO₂ in the range 0–1 CO₂ per f.u. Microscopically, the mode of NO binding near the square pyramid Cu(II) centers was directly accessed with the use of in situ NO gas adsorption X-ray Absorption Spectroscopy (XAS). Additionally, during the vacuum/temperature activation of the material and consequent NO adsorption, the electronic state of the Cu-species was monitored by observing the corresponding X-ray Near Edge Spectra (XANES). Contrary to the previously anticipated chemisorption mechanism for NO binding at Cu(II) species, we found that at slightly elevated temperatures, under ambient, but also cryogenic conditions, only relatively weak physisorption takes place, with no evidence for a particular adsorption preference to the coordinatively unsaturated Cu-centers of the material. Full article

To date, two-dimensional metal–organic frameworks (2D MOFs) have attracted much attention in many fields. Owing to their ultra-high porosity and specific surface area, great structural diversity and functional tunability, as well as feasible precision design at the molecular level, 2D MOFs have won rapid development in the field of energy storage. However, as a coordination compound, MOFs possess poor structural stability and are prone to structural collapse in electrochemical reactions, which seriously limits their electrochemical performance. Therefore, there is an urgent need to improve the structural stability of MOF electrode materials. In this study, a 2D MOF@Ti₃C₂T_X hybrid was constructed, in which urea pyrimidinone isocyanate (UPy-NCO) units were introduced via a condensation reaction with the active functional groups on MOFs, thus forming multiple hydrogen bonds among MOF frameworks to strengthen their structural stability. Importantly, 2,6-diaminopyridine was utilized to modulate the structure and properties. Initially, the mono-coordination model of the N atom on a pyridine ring with metal ions could create defects and form further pores. Two −NH₂ groups helped to improve the grafting reaction degree of UPy-NCO, leading to an increased ratio of forming quadruple hydrogen bonds (H-bonds), further strengthening the structure of the hybrid. As expected, the Cu-MOF@Ti₃C₂T_X-20%DAP-UPy hybrid exhibited a specific capacitance of 148 F g⁻¹ at 1 A g⁻¹, which is 45% higher than that of Cu-MOF@Ti₃C₂T_X-UPy (102 F g⁻¹). A good capacitance retention of 88% was obtained as the current density increased from 0.2 to 5 A g⁻¹. Moreover, excellent cycling stability (91.1%) was obtained at 1 A g⁻¹ after 5000 cycles. Full article

Sulfurization-assisted flotation is a key process that uses sulfur compounds to modify mineral surfaces, enhancing hydrophobicity and flotation efficiency, especially for copper oxide minerals. This study introduced the preliminary activation of malachite utilizing a combination of Pb²⁺ and NH₄⁺ ions in sulfurization systems, significantly improving flotation recovery. Flotation tests and surface analysis techniques were employed to examine the effects of Pb²⁺ and NH₄⁺ ions on malachite’s flotation behavior and the stability of its sulfurized surface layer. The results showed that, after activation with Pb²⁺ and NH₄⁺ at optimal reagent concentrations, malachite’s flotation recovery reached 94.6%, compared to 68.13% with traditional sulfurization. Atomic force microscopy (AFM) revealed significant changes in malachite’s surface morphology, with a dense, cloud-like sulfide film forming that contained more sulfur than in direct sulfurization, enhancing the durability of the sulfurized surface. Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) analysis confirmed increased sulfide ion adsorption on the surface compared to traditional sulfurization. The Pb²⁺ + (NH₄)₂S + Na₂S system generated numerous active sites from copper-sulfide species, promoting the growth of sulfurized phases. FT-IR analysis showed stable Cu-S species on the malachite surface, improving SBX adsorption and flotation performance. Contact angle measurements indicated that the activation systems significantly improved surface hydrophobicity, with the copper-sulfide film achieving a contact angle of 95.29°, demonstrating superior durability and mineral recovery compared to traditional sulfurization. Thus, the activation of Pb²⁺ and NH₄⁺ ions offers a promising solution for sulfurization-assisted flotation, enabling more efficient and sustainable recovery of malachite ore, with improved sulfide layer durability and enhanced hydrophobicity. Full article

Familial amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by the selective degeneration of motor neurons. Among the main genetic causes of ALS, over 200 mutations have been identified in the Cu/Zn superoxide dismutase (SOD1) protein, a dimeric metalloenzyme essential for converting superoxides from cellular respiration into less toxic products. Point mutations in SOD1 monomers can induce protein misfolding, which spreads to wild-type monomers through a prion-like mechanism, leading to dysfunctions that contribute to the development of the disease. Understanding the structural and functional differences between the wild-type protein and its mutated variants, as well as developing drugs capable of inhibiting the propagation of misfolding, is crucial for identifying new therapeutic strategies. In this work, seven SOD1 mutations (A4V, G41D, G41S, D76V, G85R, G93A, and I104F) were selected, and three-dimensional models of SOD1 dimers composed of one wild-type monomer and one mutated monomer were generated, along with a control dimer consisting solely of wild-type monomers. Molecular dynamics simulations were conducted to investigate conformational differences between the dimers. Additionally, molecular docking was performed using a library of ligands to identify compounds with high affinity for the mutated dimers. The study reveals some differences in the mutated dimers following molecular dynamics simulations and in the docking of the selected ligands with the various dimers. Full article

Two new cage-structured compounds—NbCu₂Zn₂₀ and HfCu₂Zn₂₀—belonging to the MM’₂X₂₀ (M, M’ = transition or rare earth metals, and X = Al, Zn, or Cd) family of structures have been synthesized via the self-flux method. The new compounds crystallize in the space group $Fd\overline{3}m$ with lattice parameter 13.9013(2) Å for NbCu₂Zn₂₀ and 13.9856(2) Å for HfCu₂Zn₂₀. The structures follow the expected metallic radii trend in MM’₂₀Zn₂₀ (M = Nb or Hf, M’ = Mn, Fe, Co, Ni, and Cu). While NbCu₂Zn₂₀ is stoichiometric, HfCu₂Zn₂₀ exhibits Cu/Zn site mixing and Hf-site underoccupancy, resulting in a final stoichiometry of Hf_0.96Cu_1.67Zn_20.33 (Hf_1–δCu_2–xZn_20+x, δ = 0.04, x = 0.33). Full article

This manuscript highlights the behavior of biodegradable polymers (PLA and HD PLA Green) coated with two distinct bronze alloy powders, Metco 51F-NS (Cu 9.5Al 1.2Fe) and Metco 445 (Cu 9.5Al). The coating was realized on printed samples by using the Atmospheric Plasma Spray (APS) technique. The current investigation will explain the results related to the surface quality, micro-structure, morphology, and thermal and tribological properties. Thus, from a structural point of view, the most uniform deposition was obtained in the case of composite powder Metco 51F-NS. The thermal behavior of the samples coated with copper-based powder achieved stability up to temperatures slightly above 200 °C, with carbonization of the matrix structure taking place around 350 °C. The micro-indentation and scratch analysis responses were significantly influenced by the semicrystalline structure of the samples and the presence of the powder compounds. Based on the increased characteristics of the coated samples, the authors of the present paper consider that parts made of biodegradable polymers and coated with copper microparticles are appropriate for some applications which take place in adverse operating conditions. Full article

Oxygen-bearing platinum group minerals (O-bearing PGMs) are intergrown with base metal sulfides (BMS, e.g., pentlandite–[NiFe]₉S₈) within fractures in chromite grains from chromitite bodies on Ouen Island, New Caledonia. These PGMs are hosted in chlorite and serpentine, which formed during serpentinization of olivine and pyroxene. The O-bearing PGM grains are polygonal, show microfracturing (indicating volume loss), and contain Pt-Pd-rich sulfide remnants, suggesting pseudomorphic replacement of primary (magmatic) sulfides. They display chemical zonation, with Pt(-Pd-Ni-Fe) relict sulfide cores replaced by Pt-Fe-Ni oxidized alloy mantles and Pt-Cu-Fe(-Pd) alloy rims (tulameenite), indicating desulfurization. The core and mantle show a nanoporous structure, interpreted as the result of coupled dissolution–reprecipitation reactions between magmatic sulfides and low fO₂–fS₂ serpentinite-related fluids, probably formed during olivine transformation to serpentine + magnetite (early stages of serpentinization). This fluid infiltrated magmatic sulfides (PGE-rich and BMS), degrading them to secondary products and releasing S and metals that were accommodated in the mantle and rim of O-bearing PGMs. Upon olivine exhaustion, an increase in fO₂ might have stabilized Pt-Fe-O compounds (likely Pt⁰/Pt-Fe + Fe oxyhydroxides) alongside Ni-Fe alloys. Our results show that post-magmatic desulfurization of primary sulfides produces complex nano-scale intergrowths, mainly driven by changes in the fluid’s physicochemical properties during serpentinization. Full article

Kale (Brassica napus) and collard (Brassica oleracea) are two leafy greens in the family Brassicaceae. The leaves are rich sources of numerous health-beneficial compounds and are commonly used either fresh or cooked. This study aimed to optimize the nutrient management of kale and collard in hydroponic production for greater yield and crop quality. ‘Red Russian’ kale and ‘Flash F1’ collard were grown for 4 weeks after transplanting in a double polyethylene-plastic-covered greenhouse using a nutrient film technique (NFT) system with 18 channels. Kale and collard were alternately grown in each channel at four different electrical conductivity (EC) levels (1.2, 1.5, 1.8, and 2.1 mS·cm⁻¹). Fresh and dry yields of kale increased linearly with increasing EC levels, while those of collard did not increase when EC was higher than 1.8 mS·cm⁻¹. Kale leaves had significantly higher P, K, Mn, Zn, Cu, and B than the collard at all EC levels. Additionally, mineral nutrients (except N and Zn) in leaf tissue were highest at EC 1.5 and EC 1.8 in both the kale and collard. However, the changing trend of the total N and NO3- of the leaves showed a linear trend; these levels were highest under EC 2.1, followed by EC 1.8 and EC 1.5. EC levels also affected phytochemical accumulation in leaf tissue. In general, the kale leaves had significantly higher total anthocyanin, vitamin C, phenolic compounds, and glucosinolates but lower total chlorophylls and carotenoids than the collard. In addition, although EC levels affected neither the total chlorophyll or carotenoid content in kale nor glucosinolate content in either kale or collard, other important health-beneficial compounds (especially vitamin C, anthocyanin, and phenolic compounds) in kale and collard leaves reduced with the increasing EC levels. In conclusion, the kale leaf had more nutritional and phytochemical compounds than the collard. An EC level of 1.8 mS·cm⁻¹ was the optimum EC level for the collard, while the kale yielded more at 2.1 mS·cm⁻¹. Further investigations are needed to optimize nitrogen nutrition for hydroponically grown kale. Full article

Two new organo-inorganic hybrids, (C₂N₂H₁₀)[Cu(H₂O)₄](BeF₄)₂ (1) and (C₂N₂H₁₀)[Cu(H₂O)₄](SeO₄)₂ (2), were prepared via the interaction of ethylenediamine, copper fluoroberyllate or selenate, and H₂[BeF₄]/H₂SeO₄ in aqueous solutions. The structures of 1 and 2 are similar to each other and the previously reported (C₂N₂H₁₀)[Cu(H₂O)₄](SO₄)₂: monoclinic, P2₁/c, a = 5.1044(2) Å, b = 11.6171(4) Å, c = 10.1178(3) Å, and β = 94.431(3)° for 1; and a = 5.25020(10), b = 11.7500(2), c = 10.4434(2), and β = 94.5464(17)° for 2. All structures contain a square planar [Cu(H₂O)₄]²⁺ species, which coordinates, at rather long distances, two TX₄²⁻ tetrahedral dianions in κ¹ mode, forming relatively weak [Cu(H₂O)₄(TX₄)₂]²⁻ complexes. These are linked together via hydrogen bonding into pseudo-chains; the ethylenediammonium cations link them into a 3D architecture. Compound 1 is, to the best of our knowledge, the first—though expected—representative of a hybrid organo-inorganic fluoroberyllate. The crystal chemical relations within the structural family (enH₂)[Cu(H₂O)₄](TX₄)₂ are discussed. Full article

As some previously reported studies have proven that amodiaquine, in addition to its primary antimalarial activity, also has potential for new applications such as the inhibition of cholinesterases, in our study we focused on the evaluation of the influence of different substituents in the aminoquinoline part of the amodiaquine structure on the inhibition of human acetylcholinesterase and butyrylcholinesterase to investigate the possibility for their use as drugs for the treatment of AD. We synthesized a series of amodiaquine derivatives bearing H-, F-, CF₃-, NO₂-, CN-, CO₂H- or CH₃O- groups on the aminoquinoline ring, and determined that all of the tested derivatives were very potent inhibitors of both cholinesterases, with inhibition constants (K_i) in the nM and low μM range and with prominent selectivity (up to 300 times) for the inhibition of acetylcholinesterase. All compounds displayed an ability to chelate biometal ions Fe²⁺, Zn²⁺ and Cu²⁺ and an antioxidant power comparable to that of standard antioxidants. Most of the compounds were estimated to be able to cross the blood–brain barrier by passive transport and were nontoxic toward cells that represent the models of individual organs. Considering all these beneficial features, our study has singled out compound 5, the most potent AChE inhibitor with a CH₃O- on C(7) position, followed by 6 and 14, compounds without substituent or hydroxyl groups in the C(17) position, respectively, as the most promising compounds from the series which could be considered as potential multi-target drugs for the treatment of AD. Full article

The rising levels of type 2 diabetes mellitus (T2DM) and the poor medical effects of the commercially available antidiabetic drugs necessitate the development of potent analogs to treat this multifactorial metabolic disorder. It has been demonstrated that targeting two or more biochemical targets associated with the onset and progression of diabetes along with oxidative stress and/or cancer could be a significant strategy for treating complications related to this metabolic disorder. The 3,5-dibromo-4,6-dimethoxychalcones (2a–f) and the corresponding flavone derivatives (3a–f) were synthesized and characterized using spectroscopic (NMR, HR-MS and FT-IR) techniques. The inhibitory effect of both series of compounds against α-glucosidase and α-amylase was evaluated in vitro through enzymatic assays. Selected compounds were also evaluated for potential to activate or inhibit superoxide dismutase. Compound 3c was selected as a representative model for the flavone series and evaluated spectrophotometrically for potential to coordinate Cu(II) and/or Zn(II) ions implicated in the metal-catalyzed free radical generation. A plausible mechanism for metal-chelation of the test compounds is presented. Furthermore, the most active compounds from each series against the test carbohydrate-hydrolyzing enzymes were selected and evaluated for their antigrowth effect on the human breast (MCF-7) and lung (A549) cancer cell lines and for cytotoxicity against the African Green Monkey kidney (Vero) cell line. The parent chalcone 2a and flavone derivatives 3a, 3c and 3e exhibited relatively high inhibitory activity against the MCF-7 cells with IC₅₀ values of 4.12 ± 0.55, 8.50 ± 0.82, 5.10 ± 0.61 and 6.96 ± 0.66 μM, respectively. The chalcones 2a and 2c exhibited significant cytotoxicity against the A549 cells with IC₅₀ values of 7.40 ± 0.67 and 9.68 ± 0.80 μM, respectively. Only flavone 3c exhibited relatively strong and comparable cytotoxicity against the MCF-7 and A549 cell lines with IC₅₀ values of 6.96 ± 0.66 and 6.42 ± 0.79 μM, respectively. Both series of compounds exhibited strong activity against the MCF-7 and A549 cell lines compared to the analogous quercetin (IC₅₀ = 35.40 ± 1.78 and 35.38 ± 1.78 μM, respectively) though moderate compared to nintedanib (IC₅₀ = 0.53 ± 0.11 and 0.74 ± 0.15 μM, respectively). The test compounds generally exhibited reduced cytotoxicity against the Vero cells compared to this anticancer drug. Molecular docking revealed strong alignment of the test compounds with the enzyme backbone to engage in hydrogen bonding interaction/s and hydrophobic contacts with the residues in the active sites of α-glucosidase and α-amylase. The test compounds possess favorable drug-likeness properties, supporting their potential as therapeutic candidates against T2DM. Full article

We synthesized four new copper(II) complexes with acetato and chlorido ligands and methylammonium (MA), dimethylammonium (DMA), and tetramethylammonium (TMA) counterions: (MA)₄[Cu₂Ac₄Cl₂]Cl₂·2H₂O (1), (DMA)₂[Cu₂Ac₄Cl₂] (2), (DMA)₄[Cu₂Ac₄Cl₂]Cl₂·2H₂O (3), and (TMA)₅[Cu₂Ac₄Cl]Cl₄·4H₂O (4). All compounds were characterized by single-crystal X-ray diffraction, magnetic measurements, FTIR spectroscopy, and thermogravimetric analysis. Complexes 1, 2, and 3 consist of a dinuclear coordination anion [Cu₂(Ac)₄Cl₂]²⁻ with bridging acetato ligands arranged in a paddle-wheel conformation and square-pyramidal coordination around Cu(II) atoms, while the coordination anion in compound 4 is a polymeric chain, parallel to the c axis, with Cu₂(Ac)₄ units connected through bridging chlorido ligands. Magnetic measurements carried out between 2 K and 300 K indicate strong antiferromagnetic interactions between Cu(II) ions. The effective magnetic moments range from $1.94 {\mu }_{\mathrm{B}}$ to $2.21 {\mu }_{\mathrm{B}}$, exceeding the spin-only value for Cu(II) ions (${\mu }_{\mathrm{e}\mathrm{f}\mathrm{f}}=1.73 {\mu }_{\mathrm{B}}$) and suggesting significant orbital contributions to the magnetic moment. Thermogravimetric analysis of all complexes showed a multistep decomposition behavior yielding elemental copper as the final product. Full article

The chemical investigation of the South China Sea soft coral Sinularia densa has resulted in the isolation of seven new terpenoids, including two new meroterpenoids, namely sinudenoids F–G (1–2), and five new cembranes, namely sinudenoids H–L (3–7). Their structures and absolute configurations were elucidated based on extensive analyses of spectroscopic data, single-crystal X-ray diffraction, comparison with the literature data, and quantum chemical calculations. Among them, sinudenoid F (1) and sinudenoid G (2) are rare meroterpenoids featuring a methyl benzoate core. Sinudenoid H (3) possesses a rare carbon skeleton of 8, 19-bisnorfuranocembrenolide, which is the second reported compound with this skeleton. In a bioassay, sinudenoid H (3) exhibited better anti-inflammatory activity compared to the positive control indomethacin at 20 µM in CuSO₄-treated transgenic fluorescent zebrafish. Moreover, sinudenoid J (5) and sinudenoid L (7) exhibited moderate anti-thrombotic activity in arachidonic acid (AA)-induced thrombotic zebrafish at 20 µM. Full article

Natural compounds are important precursors for the synthesis of new drugs. The development of novel molecules that are useful for various diseases is the main goal of researchers, especially for the diagnosis and treatment of many diseases. Some pathologies need to be treated with radiopharmaceuticals, and, for this reason, radiopharmaceuticals that use the radiolabeling of natural derivates molecules are arousing more and more interest. Radiopharmaceuticals can be used for both diagnostic and therapeutic purposes depending on the radionuclide. β⁺- and gamma-emitting radionuclides are used for diagnostic use for PET or SPECT imaging techniques, while α- and β⁻-emitting radionuclides are used for in metabolic radiotherapy. Based on these assumptions, the purpose of this review is to highlight the studies carried out in the last ten years, to search for potentially useful radiopharmaceuticals for nuclear medicine that use molecules of natural origin as lead structures. In this context, the main radiolabeled compounds containing natural products as scaffolds are analyzed, in particular curcumin, stilbene, chalcone, and benzofuran. Studies on structural and chemical modifications are emphasized in order to obtain a collection of potential radiopharmaceuticals that exploit the biological properties of molecules of natural origin. The radionuclides used to label these compounds are ⁶⁸Ga, ⁴⁴Sc, ¹⁸F, ⁶⁴Cu, ^99mTc, and ¹²⁵I for diagnostic imaging. Full article