Search Results (288)

Sulfonamides represent a versatile class of biologically active compounds, best known for their antibacterial activity, but increasingly investigated for their potential in oncology. Free sulfonamides themselves display cytotoxic properties; however, coordination with metal ions often enhances both selectivity and potency, while also introducing new mechanisms of action. Although numerous studies have reported sulfonamide–metal complexes with anticancer activity, a systematic overview linking biological properties to the central metal atom has been lacking. This review summarizes current research on sulfonamide complexes with transition metals and selected main-group elements, focusing on their pharmacological potential as anticancer agents. The compounds discussed include complexes of titanium, chromium, manganese, rhenium, ruthenium, osmium, iridium, palladium, platinum, copper, silver, gold, iron, cobalt, nickel, uranium, calcium, magnesium and bismuth. For each group, representative structures are presented along with cytotoxicity data against cancer cell lines, comparisons with reference drugs such as for example cisplatin, and where relevant, studies on carbonic anhydrase inhibition. The survey of available data demonstrates that many sulfonamide–metal complexes show cytotoxic activity comparable to or greater than existing chemotherapeutic agents, while in some cases exhibiting reduced toxicity toward non-cancerous cells. These findings highlight the promise of sulfonamide–metal complexes as a fertile area for anticancer drug development and provide a framework for future design strategies. This review covers the research on anti-cancer activity of sulfonamide complexes during the years 2007–2025. Full article

In industrial processes, catalysts—materials that speed up chemical reactions without being consumed—are essential. The goal of this research was to create two new rhenium-based nanocomposite catalysts that can effectively and sustainably reduce nitroaromatic compounds to aromatic amines in continuous-flow systems. Nitroaromatic hydrocarbons (NACs), widely used in manufacturing pharmaceuticals, insecticides, and herbicides, often contaminate soil and water, posing significant environmental and health risks. However, their reduction to aromatic amines enables potential industrial reuse. In this study, we synthesized two nanocomposite catalysts based on a copolymer functionalized with N-methyl-D-glucamine, embedded with rhenium (Re)-based apparent nanoparticles, and used them to reduce the NACs in continuous-flow mode to their aromatic amines using newly designed and stereolithographic (SLA) 3D-printed reactors. Advanced characterization techniques were employed to evaluate their structure, morphology, and catalytical performance. Catalyst 1, prepared from a self-modified Purolite D4869 resin and characterized by higher Re loading, exhibited superior conversion rates in batch mode (k₁ up to 1.406 s⁻¹). In contrast, Catalyst 2, based on a commercial NMDG-functionalized Dowex resin with a mesoporous structure, demonstrated remarkable stability and catalytic capacity under continuous flow (up to 1.383 mmol_NAC mL_cat⁻¹). Overall, Catalyst 1 was found to be better suited for rapid batch reactions, whereas Catalyst 2 was found to be more appropriate for long-term flow applications, offering a sustainable route for the efficient conversion of nitroaromatic compounds into valuable aromatic amines. The reactors enabled the efficient conversion of NACs into aromatic amines while enhancing process sustainability and efficiency. Full article

CdS is a promising photocatalyst for solar-driven hydrogen production due to its favorable optical properties and electronic structure. However, rapid recombination of photogenerated carriers and photocorrosion significantly limit its practical application. In this study, we developed a sustainable strategy by constructing CdS/ReS₂ nanocomposites through hydrothermal interfacial engineering. On this basis, ReS₂ nanosheets were intercalated on the surface of CdS by the hydrothermal method for catalyst modification. The introduction of ReS₂ can effectively enhance the photoelectrochemical performance of CdS and accelerate the transfer of photogenerated carriers. The effects of different ReS₂ loadings on the photocatalytic activity of CdS were explored experimentally, and the data revealed that the photocatalytic hydrogen evolution efficiency reached 50 mmol g⁻¹ h⁻¹ when the loading amount of ReS₂ was 7 wt% and did not show any obvious attenuation during four cycles. This study provides a robust surface engineering strategy to enhance the catalytic efficiency of CdS photocatalysts and provides a theoretical basis for its application in photocatalytic hydrogen precipitation. This study also emphasizes the potential of abundant, non-precious metal materials for promoting scalable, environmentally friendly hydrogen production technologies that align with the principles of green chemistry and sustainable energy systems. Full article

The thioether-functionalized 2-azabutadiene (ⁱPrS)₂C=C(H)-N=CPh₂ L1 ligates to Mn(CO)₅Br to form the five-membered chelate compound fac-MnBr(CO)₃[(ⁱPrS)₂C=C(H)-N=CPh₂] MnPropBr, whose crystal structure has been determined from X-ray diffraction data. In the crystal, different secondary intermolecular interactions, such as Br^…HC and π^…π, give rise to a supramolecular network. The electronic properties of the metal–ligand bonds in MnPropBr are similar to those of complex MnPhBr (with R = SPh instead of ⁱPrS); this also applies to a series of structurally analogous fac-ReX(CO)₃[(RS)₂C=C(H)-N=CPh₂] (X = Cl, Br and I; R = SⁱPr, SPh and S^tBu) rhenium complexes and are discussed on the basis of QT-AIM (Quantum Theory of Atoms in Molecules) calculations. New bond length/electron density relationships are proposed for the metal–halide bonds, including, for the first time, complexes of one given metal and all three corresponding halides. In order to obtain a set of coherent data, three manganese complexes that belong to the family fac-MnX(CO)₃[N∩N] (X = Cl, Br and I; N∩N is a chelating ligand with two coordinating N atoms) were included in this study. Full article

This paper presents the research results on the synthesis of rhenium catalysts MTO, Re₂O₇/Al₂O₃, and M-Re₂O₇/Al₂O₃ (where M = Ni, Ag, Co, Cu) from rhenium compounds (ammonium perrhenate, perrhenic acid, nickel(II) perrhenate, cobalt(II) perrhenate, zinc perrhenate, silver perrhenate, and copper(II) perrhenate) derived from waste materials. Methyltrioxorhenium (MTO) was obtained from silver perrhenate with a yield of over 80%, whereas when using nickel(II), cobalt(II), and zinc perrhenates, the product was contaminated with tin compounds and the yield did not exceed 17%. The Re₂O₇/Al₂O₃ and M-Re₂O₇/Al₂O₃ catalysts were obtained from the above-mentioned rhenium compounds. Alumina obtained in a calcination process of aluminum nitrate nonahydrate was used as a support. The catalysts were characterized in terms of their chemical and phase composition and physicochemical properties. Catalytic activity in model reactions, such as cyclohexene epoxidation and hex-1-ene homometathesis, was also studied. MTO obtained from silver perrhenate showed >70% activity in the epoxidation reaction, thus surpassing commercial MTO (1.0 mol% MTO, room temperature, and reaction time—2 h). Ag-Re₂O₇/Al₂O₃, Cu-Re₂O₇/Al₂O₃, and H-Re₂O₇/Al₂O₃ catalysts were inactive, while Co-Re₂O₇/Al₂O₃ and Ni-Re₂O₇/Al₂O₃ showed low activity (<43%) in the hex-1-ene homometathesis reaction. Only Re₂O₇/Al₂O₃ catalysts achieved >70% activity in this reaction (2.5 wt% Re, room temperature, and reaction time—2 h). The results indicate the potential of using rhenium compounds derived from waste materials to synthesize active catalysts for chemical processes. Full article

A previously synthesized and functionalized magnetic glycidyl methacrylate-based nanocomposite, mPGMT-deta, was tested as a sorbent for Re(VII) oxoanions in Mo(VI)-containing solutions. The effect of pH on the removal efficiency and the separation factor was examined in the range of 2 to 9. A maximum separation factor (β_Re/Mo) of 8.85 was observed at pH 6. The nature of rhenium oxoanions binding to the active sites of mPGMT-deta was analyzed using density functional theory (DFT). The calculations indicated that the formation of MoO₄²⁻//hedetaH₂²⁺ adduct is electrostatically favored at pH 6, while the inclusion of solvation effects makes the formation of ReO₄⁻//hedetaH₂²⁺ adduct thermodynamically more favorable. Solvation played a dominant role in determining the selectivity of oxoanion sorption to the nanocomposite. The adsorption isotherm, kinetics, and thermodynamics of Re(VII) onto mPGMT-deta were determined. The equilibrium data were best-fitted using the Langmuir adsorption model (R² = 0.999), with a maximum sorption capacity for Re(VII) of 0.43 mmol/g. The uptake kinetics of the sorption process obeyed the pseudo-second-order model, with the influence of diffusion and external mass transfer. Based on the thermodynamic parameters, Re(VII) sorption was spontaneous and endothermic. Full article

The efficient recovery of rhenium (Re), a critical metal in high-tech industries, is essential to address its growing demand and reduce reliance on primary mining. In this study, we developed novel anion-exchange resins for the selective adsorption and recovery of Re(VII) ions from acidic solutions, simulating industrial by-products. The resins were synthesized from a vinylbenzyl chloride-co-divinylbenzene copolymer modified with aliphatic, heterocyclic, and aromatic weakly basic amines, selected from among bis(3-aminopropyl)amine (BAPA), 1-(2-pyrimidinyl)piperazine (PIP), thiosemicarbazide (TSC), 2-amino-3-hydroxypyridine (AHP), 1-(2-hydroxyethyl)piperazine (HEP), 4-amino-2,6-dihydroxypyrimidine (AHPI), and 2-thiazolamine (TA). The adsorption of Re on BAPA, PIP, and HEP resins obeyed the Langmuir model, and the resins exhibited high adsorption capacities, with maximum values reaching 435.4 mg Re g⁻¹ at pH 6. Furthermore, strong selectivity for ReO₄⁻ ions over competing species, including Mo, Cu, and V, was noted in solutions simulating the leachates of the by-products of Cu-Mo ores. Additionally, complete elution of Re was possible. The developed resins turned out to be highly suitable for the continuous-flow-mode adsorption of ReO₄⁻, revealing outstanding adsorption capacities before reaching column breakthrough. In this context, the novel anion-exchange resins developed offer a reference for further Re recovery strategies. Full article

The use of radiosensitizers is a beneficial approach in cancer radiotherapy treatment. However, the enhancement of radiation effects on cancer cells by radiosensitizers involves several different mechanisms, reflecting the chemical nature of the radiosensitizer. G-quadruplex (G4) DNA ligands have emerged in recent years as a potential new class of radiosensitizers binding to specific DNA sequences. Recently, we have shown that the Re(I) tricarbonyl complex PDF-Pz-Re and its pyrazolyl-diamine chelator PDF-Pz, carrying a N-methylated pyridostatin (PDF) derivative, act as G4 binders of various G4-forming DNA and RNA sequences. As described in this contribution, these features prompted us to evaluate PDF-Pz-Re and PDF-Pz as radiosensitizers of prostate cancer PC3 cells submitted to concomitant treatment with Co-60 radiation. The compound RHPS4 was also tested, as this G4 ligand was previously shown to exhibit strong radiosensitizing properties in other cancer cell lines. The assessment of the resulting radiobiological effects, namely through clonogenic cell survival, DNA damage, and ROS production assays, showed that PDF-Pz-Re and PDF-Pz were able to radiosensitize PC3 cells despite being less active than RHPS4. Our results corroborate that G4 DNA ligands are a class of compounds with potential interest as radiosensitizers, deserving further studies to optimize their radiosensitization activity and elucidate the mechanisms of action. Full article

Many bcc refractory alloys show excellent high-temperature mechanical properties, while their fabricability can be limited by brittleness near room temperature. For the purpose of predicting ductile alloys, a number of ductility metrics based on atomic structures and crystal properties, ranging from mechanistic to empirical, have been proposed. In this work, we propose an “average bond stiffness” as a new ductility metric that is also convenient to obtain from first-principles calculations, in addition to using the average magnitude of static displacements of atoms. The usefulness of average bond stiffness is validated by comparing first-principles calculation results to experimental data on the “rhenium effect” in Mo/W-base and V/Nb/Ta-base binary alloys. The average bond stiffness also correlates well with the room-temperature ductility of refractory high-entropy alloys, with a better performance than some ductility metrics previously reported. While in reality the ductility of an alloy can be influenced by many factors, from processing and microstructure, the average magnitude of static displacements and the average bond stiffness are atomistic-level features useful for design of alloy composition towards a desired level of ductility. Full article

Antimicrobial resistance (AMR) poses a critical global health threat by rendering existing antibiotics ineffective against infections, leading to increased mortality, prolonged illnesses, and higher healthcare costs. Developing new antibiotics is essential to combat resistant pathogens, safeguard modern medical procedures, and prevent a return to a pre-antibiotic era where common infections become untreatable. We report a series of chiral tricarbonyl rhenium(I) complexes incorporating enantiopure pinene-substituted bipyridine ligands (L#) of the general formula fac-[Re(CO)₃L#X] and fac-[Re(CO)₃L#Py]⁺ (where X = Cl or Br and Py = pyridine). These complexes were isolated as mixtures of two diastereomers, characterized by standard techniques, and evaluated for cytotoxic activity against methicillin-resistant and methicillin-sensitive Staphylococcus aureus (MRSA and MSSA). The results revealed notable antibacterial efficacy (MIC = 1.6 μM), reflected in high therapeutic indices (Ti > 10). In contrast, analogous complexes bearing non-chiral 2,2′-bipyridine ligands exhibited no activity, underscoring the critical role of chirality in modulating biological interactions at the molecular level. These findings highlight the potential of chiral Re(I) complexes as promising scaffolds for the development of more potent and selective antibacterial agents. Full article

In the present work, we design a laminated composite composed of molybdenum–rhenium alloy and silicon carbide ceramics for use in space reactors as a candidate structural material with neutron spectral shift properties. The influence of the internal microstructure on the mechanical properties is investigated by finite element simulation based on scale separation. The results of the study showed that the incorporation of gradient transition layers between the metallic and ceramic phases effectively mitigates thermally induced local stresses arising from mismatches in coefficients of thermal expansion. By optimizing the composition of the gradient transition layers, the stress distribution within the composite under operating conditions has been adjusted. As a result, the stress experienced by the alloy phase is significantly reduced, potentially extending the high-temperature creep rupture life. Full article

The use of metal-based complexes is currently taking centre stage in the field of nanomedicine for the treatment and control of various ailments. Rhenium(I) tricarbonyl complexes have frequently been evaluated in vitro for their anticancer activities, and a few have advanced to in vivo and clinical trials, owing to the distinct application characteristics of these complexes. Their inception in drug development is key. This study explores a detailed chronological overview of the medical applications of Re(I) tricarbonyl complexes over the past six years (2019–2024), focusing on their applications and clinical tests in the control and management of various ailments. An in-depth examination of their activities in anticancer treatments, Chagas disease, antifungal infections, antimalarial, and microbial infections was conducted, comparing the complexes to various standard antibiotics, conventional antimalarial drugs, antifungals, and standard anticancer agents. Full article

Hyperbolic plasmons are a highly desired property in optoelectronics and biomolecular sensing. The necessary condition to realize hyperbolic plasmons is a significant anisotropy of the principal components of the dielectric function, such that at a certain frequency range, one component is negative and the other is positive, i.e., one component is metallic, and the other one is dielectric. Here, we study the effect of anisotropy in ${\mathrm{ReS}}_2$, and our theory shows that ${\mathrm{ReS}}_2$ can host hyperbolic plasmons in the ultraviolet frequency range. The operating frequency range of the hyperbolic plasmons can be tuned with the number of ${\mathrm{ReS}}_2$ layers. However, we note that the significantly large imaginary part of the macroscopic dielectric response in all layered variants of ReS₂ can result in substantial losses for the hyperbolic plasmons, as in the case with other known hyperbolic materials, with the exception of MoOCl₂. We also note that ReS₂ hosts ultraviolet hyperbolic plasmons while ZrSiSe, WTe₂, and CuS nanocrystals host infrared plasmons, providing a novel platform for optoelectronics in the ultraviolet range. Full article

One of the key challenges in commercializing proton exchange membrane (PEM) electrolyzer technology is reducing the production costs while maintaining high efficiency and operational stability. Significant contributors to the overall cost of the device are the electrode catalysts with IrO₂ and Pt/C. Due to the high cost and limited availability of noble metals, there is growing interest in developing alternative, low-cost catalytic materials. In recent years, two-dimensional transition metal dichalcogenides (2D TMDCs), such as molybdenum disulfide (MoS₂) and rhenium disulfide (ReS₂), have attracted considerable attention due to their promising electrochemical properties for hydrogen evolution reactions (HERs). These materials exhibit unique properties, such as a high surface area or catalytic activity localized at the edges of the layered structure, which can be further enhanced through defect engineering or phase modulation. To increase the catalytically active surface area, the investigated materials were deposited on a carbon-based support—Vulcan XC-72R—selected for its high electrical conductivity and large specific surface area. This study investigated the physicochemical and electrochemical properties of six catalyst samples with varying MoS₂ and ReS₂ to carbon support ratios. Among the composites analyzed, the best sample on MoS₂ (containing the most carbon soot) and the best sample on ReS₂ (containing the least carbon soot) were selected. These were then used as cathode catalysts in an experimental PEM electrolyzer setup. The results confirmed satisfactory catalytic activity of the tested materials, indicating their potential as alternatives to conventional noble metal-based catalysts and providing a foundation for further research in this area. Full article

The aim of this study was to improve the water–gas shift efficiency of Co/CeO₂ catalyst by incorporating praseodymium and rhenium. The catalysts were synthesized via combustion method and characterized using X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area analysis, Scanning Electron Microscope (SEM), H₂-temperature programmed reduction (H₂-TPR), NH₃-temperature programmed desorption (NH₃-TPD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). These characterization techniques evaluate the increase of the surface acidity and oxygen vacancies in Co-based catalysts, which leads to an increase in water–gas shift performance because CO molecules prefer to react with surface oxygen, then followed by the production of CO₂ and oxygen vacancies which act as active sites for H₂O dissociation. The 1%Re4%Co/Ce-5%Pr-O catalyst exhibited a maximum CO conversion of 86% at 450 °C, substantially outperforming the 5%Co/Ce-5%Pr-O catalyst, which showed only 62% CO conversion at 600 °C. In addition, 1%Re4%Co/Ce-5%Pr-O catalyst is more resistant towards deactivation than 5%Co/Ce-5%Pr-O. The result presented that the catalytic activity of 1%Re4%Co/Ce-5%Pr-O catalyst was kept constant for the whole period of 50 h, while a 6% decrease in water–gas shift activity was found for the 5%Co/Ce-5%Pr-O catalyst. Moreover, the addition of rhenium into the Co/Ce-Pr-O catalyst reveals that the enhancement of oxygen vacancy concentration, oxygen mobility, and surface acidity, thereby enhances CO conversion efficiency. Full article