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The reaction of Re(CO)5Br with deprotonated 1H‐(5‐(2,2′:6′,2′′‐terpyridine)pyrid‐2‐yl)tetrazole yields a triangular assembly formed by tricarbonyl Re(I) vertices. Photophysical measurements reveal blue‐green emission with a maximum at 520 nm, 32 % quantum yield, and 2430 ns long‐lived excited state decay lifetime in deaerated dichloromethane solution. Coordination of lanthanoid ions to the terpyridine units red‐shifts the emission to 570 nm and also reveals efficient (90 %) and fast sensitisation of both Eu(III) and Yb(III) at room temperature, with a similar rate constant kET on the order of 107 s−1. Efficient sensitisation of Eu(III) from Re(I) is unprecedented, especially when considering the close proximity in energy between the donor and acceptor excited states. On the other hand, comparative measurements at 77 K reveal that energy transfer to Yb(III) is two orders of magnitude slower than that to Eu(III). A two‐step mechanism of sensitisation is therefore proposed, whereby the rate‐determining step is a thermally activated energy transfer step between the Re(I) centre and the terpyridine functionality, followed by rapid energy transfer to the respective Ln(III) excited states. At 77 K, the direct Re(I) to Eu(III) energy transfer seems to proceed via a ligand‐mediated superexchange Dexter‐type mechanism. [ABSTRACT FROM AUTHOR]

Hydrogen is seen as an ideal alternative fuel to fossil fuels because it is green and sustainable. With the increasing energy crisis, developing efficient catalysts for hydrogen production to alleviate resource depletion is urgent. As a new member in the family of two-dimensional (2D) transition metal dichalcogenides (TMDs), 2D rhenium disulfide have attracted much attention based on their unique properties. In this paper, based on the unusual structural features and excellent properties of 2D rhenium disulfide, we cite their applications in the field of electrocatalytic water splitting and provide an in-depth understanding of the reaction mechanism. Furthermore, we enumerate the various synthetic methods of 2D rhenium disulfide and summarize the different strategies and current research progress in modulating their catalytic performances. Finally, we discuss the challenges faced by 2D rhenium disulfide in terms of synthetic methods and modulation strategies, and provide insights into their possible future development directions, hoping to provide valuable guidance for the design and preparation of high-performance rhenium-based electrocatalysts in the future. [Display omitted] • The unique structure and properties of 2D rhenium disulfide are presented. • Various synthetic methods of 2D rhenium disulfide are summarized. • Strategies for improving the catalytic performances are discussed. [ABSTRACT FROM AUTHOR]

Nine potentially bidentate thiosemicarbazone (HLn) ligands and their tricarbonylrhenium(I) complexes, [ReY(HLn)(CO)3] (Y=Cl, Br), were synthesized and their binding affinity towards the alpha and beta receptors were determined using a competitive standard radiometric assay with [3H]‐estradiol. Even in the absence of a base, coordinated thiosemicarbazones can undergo deprotonation causing the release of the coordinated halide forming dimeric species, [Re2(Ln)2(CO)6]. The observation of the formation of the dinuclear complex where the thiosemicarbazone ligand adopts the zwitterionic form, [Re2(HL9)2(CO)6]Br2, motivated the theoretical study of the relative stability of these species. Despite the ease of formation of the dimer complexes, it was possible to optimize a synthetic route to obtain the [2+1] complexes [Re(Ln)(pym)(CO)3] where pym is the monodentate ligand 4‐dimethylamino‐pyridine or 4‐hydroxy ‐pyridine. The inclusion of this additional ligand substantially improves the affinity against the receptors (in some cases against both). [99mTc(Ln)(pym)(CO)3] complexes were also prepared using [99mTc(H2O)(CO)3]+, an excess of HLn ligand and in the presence of pym. The radiochromatograms show the formation of the [2+1] complex but also the presence of species resulting from the substitution of pym by chloride and water. However, the ratio of intensities between the three signals remains constant with the variation of the relative concentration of the three monodentate ligands suggesting an equilibrium between the three complexes. [ABSTRACT FROM AUTHOR]

The very limited number of structurally known thionitrosyl complexes of technetium was increased by the synthesis of [TcII(NS)Cl3(PPh3)2] (3) and [TcII(NS)Cl3(PPh3)(OPPh3)] (4) and their reaction products with hydrotris(pyrazolyl)borates, {HB(pzR)3}−. Similar reactions were conducted with [TcI(NO)Cl2(PPh3)2(CH3CN)] and related rhenium thionitrosyls. Remarkably, most such reactions result in a rapid cleavage of the boron–nitrogen bonds of the ligands and the formation of pyrazole complexes of the two group 7 metals. Only one compound with an intact {HB(pzR)3}− ligand could be isolated: the technetium(I) complex [TcI(NO)Cl(PPh3){HB(pz)3}] (2). Other products show the coordination of one or four neutral pyrazole ligand(s) in the coordination spheres of technetium generated by thermal decomposition of the pyrazolylborates [TcI(NO)Cl2(PPh3)2(pzH)] (1) and [TcI(NS)Cl(pzHMe2)4]+ (5). Reactions with the corresponding thionitrosylrhenium complex [ReII(NS)Cl3(PPh3)2] require higher temperatures and only compounds with one pyrazole ligand, [ReI(NS)Cl2(PPh3)(pzHR)] (6a–6c), were isolated. The products were studied spectroscopically and by X-ray diffraction. [ABSTRACT FROM AUTHOR]

4-(2-furyl)-3-buten-2-one (FAc) is obtained by aldol condensation of furfural and acetone and has been used in hydrodeoxygenation reactions to obtain fuel products using noble metal catalysts. The hydrogenation of FAc in the aqueous phase using metallic- and Re oxide-supported catalysts on graphite was studied, within a temperature range of 200–240 °C, in a batch reactor over a 6 h reaction period. The catalysts were characterized using N2 adsorption–desorption, TPR-H2, TPD-NH3, XRD, and XPS analyses. Catalytic reactions revealed that metallic rhenium and rhenium oxide-supported catalysts are active for the hydrogenation and Piancatelli rearrangement of FAc. Notably, metallic rhenium exhibited a fourfold higher initial rate than rhenium oxide, which was attributed to the higher dispersion of Re in the Re/G catalyst over graphite. Re/G and ReOx/G catalysts tended to rearrange and hydrogenate FAc to 2-(2-oxopropyl)cyclopenta-1-one in water. [ABSTRACT FROM AUTHOR]

A blue fluorescent tetraphenylethylene-based dication and a red-NIR phosphorescent rhenium octahedral cluster tetra-anion are associated electrostatically to generate a supramolecular ionic framework which crystallizes in the P1¯ centric space group. The emission properties of the hybrids are studied in the crystalline state and in solution revealing a resonant energy transfer and a high sensitivity toward oxygen. [ABSTRACT FROM AUTHOR]

In contrast to corresponding nitrosyl compounds, thionitrosyl complexes of rhenium and technetium are rare. Synthetic access to the thionitrosyl core is possible by two main approaches: (i) the treatment of corresponding nitrido complexes with S2Cl2 and (ii) by reaction of halide complexes with trithiazyl chloride. The first synthetic route was applied for the synthesis of novel rhenium and technetium thionitrosyls with the metals in their oxidation states "+1" and "+2". [MVNCl2(PPh3)2], [MVNCl(PPh3)(LOMe)] and [MVINCl2(LOMe)] (M = Re, Tc; {LOMe}− = (η5-cyclopentadienyl)tris(dimethyl phosphito-P)cobaltate(III)) complexes have been used as starting materials for the synthesis of [ReII(NS)Cl3(PPh3)2] (1), [ReII(NS)Cl3(PPh3)(OPPh3)] (2), [ReII(NS)Cl(PPh3)(LOMe)]+ (4a), [ReII(NS)Cl2(LOMe)] (5a), [TcII(NS)Cl(PPh3)(LOMe)]+ (4b) and [TcII(NS)Cl2(LOMe)] (5b). The triphenylphosphine complex 1 is partially suitable as a precursor for ongoing ligand exchange reactions and has been used for the synthesis of [ReI(NS)(PPh3)(Et2btu)2] (3a) (HEt2btu = N,N-diethyl-N′-benzoyl thiourea) containing two chelating benzoyl thioureato ligands. The novel compounds have been isolated in crystalline form and studied by X-ray diffraction and spectroscopic methods including IR, NMR and EPR spectroscopy and (where possible) mass spectrometry. A comparison of structurally related rhenium and technetium complexes allows for conclusions about similarities and differences in stability, reaction kinetics and redox behavior between these 4d and 5d transition metals. [ABSTRACT FROM AUTHOR]

This study outlines findings from an investigation into the development of a hydrometallurgical process for manufacturing various forms of zinc perrhenate, entirely from waste from recycling and from the Zn–Pb industry. Scraps of Re-bearing Ni-based superalloys and acidic waste, circulating zinc solutions generated during the production of Zn by the electrolytic method and which contain >45 g/dm3 of Zn, Na, Mn, and Mg, were used in the research. In the publication, the conditions for the production of three types of zinc perrhenate, i.e., Zn(ReO4)2·4H2O, Zn(ReO4)2, and Zn(ReO4)2·2H2O, are presented. As a result of the analysis of the obtained results, it was concluded that to obtain the above-mentioned forms of zinc perrhenate, zinc carbonate can be used, precipitated from acidic, waste, and multi-component solutions after their prior neutralization to pH 4.0 and partial purification from Mn, Mg, and Na using metallurgical zinc oxide. Zinc carbonate should be precipitated using Na2CO3 at pH 6.3 and subsequently purified from other impurities, i.e., Mg, Na, and Mn, using aqueous ammonia solutions. As a result, zinc carbonate was obtained, which was used in a reaction with an aqueous solution of HReO4 to produce zinc perrhenate. The precipitated forms of Zn(ReO4)2 were obtained by appropriately drying the crude and hydrated Zn(ReO4)2 to obtain its tetrahydrate, dihydrate, and anhydrous forms, respectively, using drying temperatures of 55, 135, and 185 °C. The developed technology has been submitted for a patent and is an example of a technology founded on the principles of sustainable development, with a particular emphasis on the minimalization of loss of rhenium and zinc at all stages of its realization. [ABSTRACT FROM AUTHOR]

Recently, rhenium (Re) based ohmic contacts to GaN have been studied for their low resistivity, smooth surface morphology, and sharp edge acuity at low annealing temperatures. In this work, we discuss the evolution of surface microstructures for Re‐Al‐Ni‐Au ohmic contacts on n‐GaN as a function of Re layer thickness and annealing temperature. For all Re thicknesses, the Al and Ni segregate into agglomerates that increase in size with increasing annealing temperature. These agglomerates are surrounded by Al‐Au films. Along with the underlying Re layer, they form different crystallographic phases of Re‐Al‐Ni, Al6Re, AlAu2, and Al2Au5. This, along with the formation of Re‐N phases at the metal‐semiconductor interface leads to low resistivity ohmic contacts on n‐GaN. Investigating the evolution of the contact microstructure is an important step in understanding the behavior of the Re‐based ohmic contact system. [ABSTRACT FROM AUTHOR]

The application of a gate voltage to control the superconducting current flowing through a nanoscale superconducting constriction, named as gate-controlled supercurrent (GCS), has raised great interest for fundamental and technological reasons. To gain a deeper understanding of this effect and develop superconducting technologies based on it, the material and physical parameters crucial for the GCS effect must be identified. Top-down fabrication protocols should also be optimized to increase device scalability, although studies suggest that top-down fabricated devices are more resilient to show a GCS. Here, we investigate gated superconducting nanobridges made with a top-down fabrication process from thin films of the non-centrosymmetric superconductor niobium rhenium with varying ratios of the constituents (NbRe). Unlike other devices previously reported and made with a top-down approach, our NbRe devices systematically exhibit a GCS effect when they were fabricated from NbRe thin films with small grain size and etched in specific conditions. These observations pave the way for the realization of top-down-made GCS devices with high scalability. Our results also imply that physical parameters like structural disorder and surface physical properties of the nanobridges, which can be in turn modified by the fabrication process, are crucial for a GCS observation, providing therefore also important insights into the physics underlying the GCS effect. [ABSTRACT FROM AUTHOR]

Porphyry-epithermal veins hosting Re-rich molybdenite and rheniite (ReS2) from the Maronia Cu-Mo ± Re ± Au porphyry in Thrace, NE Greece, provide new insights into the hydrothermal processes causing extreme Re enrichment. Quartz trace element chemistry (Al/Ti, Ge/Ti), Ti-in-quartz thermometry, and cathodoluminescence imaging reveal multiple quartz generations in consecutive hydrothermal quartz-sulfide veins associated with potassic, sericitic, and argillic alteration. Fluid inclusions in different quartz generations indicate that phase separation and fluid cooling are the main ore-forming processes in the porphyry stage (~ 500 – 350 °C), whereas mixing of a vapor-rich fluid with metalliferous (e.g., Pb, Zn, Au) meteoric water forms the epithermal veins (~ 280 °C). These processes are recorded by trace element ratios in pyrite that are sensitive to changes in fluid temperature (Se/Te), fluid salinity (As/Sb, Co/As), and mixing between fluids of magmatic and meteoric origin (Se/Ge). Highly variable intra-grain δ34S values in pyrite record S isotope fractionation during SO2 disproportionation and phase separation, emphasizing the importance of in situ δ34S analysis to unravel ore-forming processes. High δ34S (~ 4.5‰) values of sulfides are indicative of low SO42−/H2S fluid ratios buffered by the local host rocks and mixing of the magma-derived fluid with meteoric water. The formation of Re-rich molybdenite (~ 6600 ppm) is favored by cooling and reduction of a magma-derived, high-temperature (~400 °C), oxidized, and Re-rich fluid triggering efficient Re precipitation in early veins in the potassic alteration zone. The systematic temporal fluid evolution therefore reveals that coeval cooling and reduction of oxidized Re-rich fluids cause extreme Re enrichment at the Maronia porphyry system. [ABSTRACT FROM AUTHOR]

Cancer is one of the deadliest diseases worldwide. Chemotherapy remains one of the most dominant forms for anticancer treatment. Despite their clinical success, the used chemotherapeutic agents are associated with severe side effect and pharmacological limitations. To overcome these drawbacks there is a need for the development of new types of chemotherapeutic agents. Herein, the chemical synthesis and biological evaluation of dinuclear rhenium(I) complexes as potential chemotherapeutic drug candidates are proposed. The metal complexes were found to be internalized by an energy dependent endocytosis pathway, primary accumulating in the mitochondria. The rhenium(I) complexes demonstrated to induce cell death against a variety of cancer cells in the micromolar range through apoptosis. The lead compound showed to eradicate a pancreatic carcinoma multicellular tumor spheroid at micromolar concentrations. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis and characterization of the novel 2‐aminoguanidine‐derived Schiff base rhenium(I) compounds: fac‐[Re(CO)3(Hguabs)Br]Br (1) (Hguabs ⋅ Cl=2‐((benzothiazole)methyleneamino)guanidine chloride) and fac‐[Re(CO)3(guaquin)Br] (2) (guaquin=2‐((quinolin‐2‐yl)methyleneamino)guanidine). [ABSTRACT FROM AUTHOR]

The depletion of valuable mineral reserves has rendered effluents generated from mining and industrial processing activities a promising resource for the production of precious elements. The synthesis and improvement of new adsorbents to extract valuable compounds from industrial wastes and pregnant leach solutions, besides increasing wealth, can play a significant role in reducing environmental concerns. In this work, a new and low-cost adsorbent for the selective extraction of rhenium (perrhenate ions, ReO4−) was synthesized by the free-radical polymerization (FRP) of a diallyl dimethylammonium chloride monomer (quaternary amine) in the presence of a crosslinker. Various methods were employed to characterize the polymeric adsorbent. The results revealed that the designed polymeric adsorbent had a high surface area and pores with nano-metric dimensions and a pore volume of 6.4 × 10−3 cm3/g. Four environments—single, binary, multicomponent, and real solutions—were applied to evaluate the adsorbent's performance in the selective separation of Re. Additionally, these environments were used to understand the behavior of molybdenum ions, the primary competitors of perrhenate ions in the ion exchange process. In competitive conditions, using variations in qe,mix/qe, an antagonism phenomenon (qe,mix/qe < 1) occurred due to the inhibitory effect of surface-adsorbed molybdenum ions on the binding of the perrhenate ions. However, across all conditions, the separation values for Re were higher than those for the other studied elements (Mo, Cu, Fe). [ABSTRACT FROM AUTHOR]

To investigate the influence of different rhenium contents on the helium desorption behavior in tungsten–rhenium alloys, pure tungsten and tungsten–rhenium alloys were irradiated with helium under the same conditions. All irradiated samples were characterized using TDS and DBS techniques. The results indicate that the addition of rhenium can reduce the total helium desorption quantity in tungsten–rhenium alloys and slightly accelerate the reduction in the concentration of vacancy-type defects accompanying helium dissociation. The desorption activation energy of helium is approximately 2 eV at the low-temperature peak (~785 K) and about 4 eV at the high-temperature peak (~1475 K). An increase in rhenium content causes the desorption peak to shift towards higher temperatures (>1473 K), which is attributed to the formation of the stable complex structures between rhenium and vacancies. Besides, the migration of He-vacancy complexes towards traps and dynamic annealing processes both lead to the recovery of vacancy-type defects, resulting in a decrease in the positron annihilation S parameters. [ABSTRACT FROM AUTHOR]

An unreported rhenium-based calcium aluminum sodalite (CARe sodalite) has been synthesized by a traditional solid-state method. The rhenium is located in the sodalite β-cage and can be reduced under 5% H2 forming gas without breaking the cage framework. Preliminary characterizations of the structural, optical, and magnetic properties are reported. [ABSTRACT FROM AUTHOR]

This work presents the research results on the development of an innovative, hydrometallurgical technology for the production of manganese(II) perrhenate dihydrate from recycled waste. These wastes are scraps of Ni-based superalloys containing Re and scraps of Li–ion batteries containing Mn—specifically, solutions from the leaching of black mass. This work presents the conditions for the production of Mn(ReO4)2·2H2O. Thus, to obtain Mn(ReO4)2·2H2O, manganese(II) oxide was used, precipitated from the solutions obtained after the leaching of black mass from Li–ion batteries scrap and purified from Cu, Fe and Al (pH = 5.2). MnO2 precipitation was carried out at a temperature < 50 °C for 30 min using a stoichiometric amount of KMnO4 in the presence of H2O2. MnO2 precipitated in this way was purified using a 20% H2SO4 solution and then H2O. Purified MnO2 was then added alternately with a 30% H2O2 solution to an aqueous HReO4 solution. The reaction was conducted at room temperature for 30 min to obtain a pH of 6–7. Mn(ReO4)2·2H2O precipitated by evaporating the solution to dryness was purified by recrystallization from H2O with the addition of H2O2 at least twice. Purified Mn(ReO4)2·2H2O was dried at a temperature of 100–110 °C. Using the described procedure, Mn(ReO4)2·2H2O was obtained with a purity of >99.0%. This technology is an example of the green transformation method, taking into account the 6R principles. [ABSTRACT FROM AUTHOR]

The synthesis and structural characterization of new "2+1" mixed ligand fac-[Re(CO)3(OO)(L)] and Re(CO)2(OO)(L)2 complexes are reported herein. Maltol and kojic acid were chosen as bidentate OO ligands, while imidazole, isocyanocyclohexane or triphenylphosphine were selected as the monodentate ligands. The synthesis of the rhenium complexes was based on the reaction of [NEt4]2[Re(CO)3Br3] with maltol and kojic acid to generate the intermediate aqua complex fac-[Re(CO)3(OO)(H2O)], followed by the replacement of the labile aqua ligand by the monodentate ligand. Structural characterization of all Re complexes was established by NMR and IR spectroscopies, as well as two of them by single-crystal X-ray crystallography, revealing distorted octahedral geometry around the Re center. In the crystal lattice, the complexes form supramolecular networks due to the development of intermolecular interactions of the N-H⋯O, C-H⋯O and C-H⋯π type. [ABSTRACT FROM AUTHOR]

Rhenium(I) tricarbonyl complexes are widely studied for their cell imaging properties and anti-cancer and anti-microbial activities, but the complexes with S-donor ligands remain relatively unexplored. A series of six fac-[Re(NN)(CO)3(SR)] complexes, where (NN) is 2,2′-bipyridyl (bipy) or 1,10-phenanthroline (phen), and RSH is a series of thiocarboxylic acid methyl esters, have been synthesized and characterized. Cellular uptake and anti-proliferative activities of these complexes in human breast cancer cell lines (MDA-MB-231 and MCF-7) were generally lower than those of the previously described fac-[Re(NN)(CO)3(OH2)]+ complexes; however, one of the complexes, fac-[Re(CO)3(phen)(SC(Ph)CH2C(O)OMe)] (3b), was active (IC50 ∼ 10 μM at 72 h treatment) in thiol-depleted MDA-MB-231 cells. Moreover, unlike fac-[Re(CO)3(phen)(OH2)]+, this complex did not lose activity in the presence of extracellular glutathione. Taken together these properties show promise for further development of 3b and its analogues as potential anti-cancer drugs for co-treatment with thiol-depleting agents. Conversely, the stable and non-toxic complex, fac-[Re(bipy)(CO)3(SC(Me)C(O)OMe)] (1a), predominantly localized in the lysosomes of MDA-MB-231 cells, as shown by live cell confocal microscopy (λex = 405 nm, λem = 470–570 nm). It is strongly localized in a subset of lysosomes (25 μM Re, 4 h treatment), as shown by co-localization with a Lysotracker dye. Longer treatment times with 1a (25 μM Re for 48 h) resulted in partial migration of the probe into the mitochondria, as shown by co-localization with a Mitotracker dye. These properties make complex 1a an attractive target for further development as an organelle probe for multimodal imaging, including phosphorescence, carbonyl tag for vibrational spectroscopy, and Re tag for X-ray fluorescence microscopy. [ABSTRACT FROM AUTHOR]

Rhenium (Re) and uranium (U) are essential proxies in reconstructing past oceanic oxygenation evolution. However, their removal in continental shelf sediments, hotspots of early diagenesis, were previously treated as quantitatively unimportant sinks in the ocean. Here we examine the sedimentary reductive removal of Re and U and their coupling with organic carbon decomposition, utilizing the 224Ra/228Th disequilibria within the East China Sea shelf. We identified positive correlations between their removal fluxes and the rates of sediment oxygen consumption or organic carbon decomposition. These correlations enable an evaluation of global shelf reductive sinks that are comparable to (for Re) or higher than (~4-fold for U) previously established suboxic/anoxic sinks. These findings suggest potential imbalances in the modern budgets of Re and U, or perhaps a substantial underestimation of their sources. Our study thus highlights shelf sedimentary reductive removal as critical yet overlooked sinks for Re and U in the modern ocean. The sources and sinks of Re and U in the modern ocean may be imbalanced, according to sedimentary porewater analysis and assessment of reductive Re and U removal on the continental shelf [ABSTRACT FROM AUTHOR]

Background. Slurry fields of NPO PRMiTS of JSC Almalyk MMC are a technogenic deposit of rare metals. As well as waste solutions of the hydrometallurgical shop. Purpose: development of a comprehensive technology for processing technogenic rheniumcontaining raw materials containing rare and non-ferrous metals. Methodology. In the processing of sludge, solid and liquid, oxidative roasting at 600oC was used, ion exchange and extraction schemes were applied, elemental analysis was performed on Agilent 7500 IСP. Originality. Based on the analysis of samples of technogenic raw materials, new schemes of complex technologies for its processing were proposed. New approaches to the selective extraction of Mo, Re, Cu from it were proposed. Findings. Existing and promising ion exchange and extraction methods for extracting Mo, Re, Cu were tested. A process flow chart was developed. [ABSTRACT FROM AUTHOR]

Composites of rhenium (ReNP) and rhenium–copper nanoparticles (ReCuNP) were studied as catalysts for the decomposition of the oxidizer ammonium perchlorate (AP) for composite solid propellants. Both composites were prepared by reducing ammonium perrhenate (NH4ReO4) and copper chloride (CuCl2) in the presence of polyamidoamine (PAMAM) dendrimers. The PAMAM-based nanostructures were characterized by transmission electron microscopy (TEM), high resolution TEM, and X-ray photoelectron spectroscopy. ReNP@PAMAM samples showed rhenium clusters and partially oxidized spherical nanoparticles of approx. 1 nm in diameter, while ReCuNP@PAMAM comprised nanoparticles of 6 nm in average size with different shapes and high-size dispersion. The computational description demonstrated the higher stability of the interaction between copper and PAMAM than perrhenate anion due to the charge transfer from the dendrimer to the cation. The materials were evaluated for the catalytic decomposition of AP by calorimetry. The catalytic performance of ReCuNP@PAMAM was superior to that of ReNP@PAMAM, lowering the decomposition of AP at high temperatures. However, the latter composite increased the energy release drastically due to the exothermic oxidation of rhenium metal. [ABSTRACT FROM AUTHOR]

This work presents studies of the electrocatalytic properties of ternary CoWRe alloys during the hydrogen-evolution reaction in KOH solution and their corrosion properties in KOH, H2SO4 and NaCl solutions. These alloys are electrodeposited from a citrate-pyrophosphate electrolyte with potassium-perrhenate concentrations of 0.01, 0.03, and 0.05 mol⋅l−1 . As shown, the use of such alloys makes it possible to increase the exchange current density by an order of magnitude and reduce the hydrogen overvoltage by 150 mV compared to electrolytic cobalt. An increase in the content of rhenium in the alloy leads to an increase in the overvoltage of hydrogen evolution in alkaline solutions: both in the KOH solution and in the electrolyte for the deposition of the alloy that explains the high current efficiency when obtaining alloys’ coatings. As shown, the highest corrosion resistance of such coatings with the ratio Re:W = 2:4 reaches 8.9 kΩ⋅cm² in NaCl solution, and in KOH solution, it is of 3.1 kΩ⋅cm², and corrosion resistance increases in time. [ABSTRACT FROM AUTHOR]

Background: Non-melanoma skin cancers (NMSCs) are responsible for up to one-third of all human malignancies. Surgery is usually the treatment of choice, but patients often experience pain during the procedure. Topical rhenium-188 resin skin cancer treatment (RSCT) may be a valid therapeutic alternative. Methods: In this monocentric pilot study, 19 patients suffering from NMSC were treated with RSCT. Most of these patients had also experienced surgery, either because they developed a new NMSC in aftercare, or they had suffered previously from NMSC. Three RSCT-treated patients, who had no exposure to surgery so far, were paired with three matched patients, who had received surgery. We sought to evaluate and compare the patients' experience with both treatments. A questionnaire assessed patients' perceptions regarding side effects, aesthetic outcomes, wound care, fear of complications, and personal treatment preferences. Patients evaluated the different parameters of their either RSCT- or surgery-treated lesions on a scale from 0–10. Results: Patients were more afraid of complications before surgery than before RSCT (p = 0.04). Treatment with RSCT caused significantly less pain on treatment day (mean 0.56) than surgery (mean 2.32) (0 no pain, 10 maximum pain) (p = 0.02) and 14 days after the procedure (mean 0.89 versus mean 2.47) (p = 0.02). On day 14, RSCT-treated lesions were also significantly less itchy (mean 0.34) than after surgery (mean 1.50). Most patients were very satisfied with the aesthetic outcome after both RSCT (mean 8.42) and surgery (mean 8.31) (p = 0.89). In the case of a new NMSC, the majority of patients who experienced both treatments would rather be treated primarily with RSCT (44%) or would consider both options (31%); only 19% preferred surgery. Conclusion: Patients evaluated RSCT as less painful than surgery. The aesthetic outcomes of both treatments were comparable. For pain-sensitive patients, RSCT might be a preferable treatment option. [ABSTRACT FROM AUTHOR]

Rhenium separation from molybdenum in molybdenite minerals and waste leachate has become an emerging challenge. Addressing this challenge, we prepared a set of protein-based alkylamine/alkylammonium salts complexes as extradants for selective uptake of rhenium from molybdenum, where the protein component turned into the insoluble amyloid-like structure when its internal disulfide bonds were reduced, namely phase-transition process. Among them, the phase-transited lysozyme and methyletrioctyleammonium chloride complex (PTL-N263) exhibited the most efficient adsorption at the alkaline condition for the electrostatic interaction between negatively charged metal ions with positively charged center (R4N+) in N263, where negatively charged protein residues hindered the ion exchange of Cl− in N263 for larger size Mo species (Mo7O246−) than smaller size Re species (ReO4−). The adsorption follows the Freundlich model and pseudo-second-order kinetics, which exhibits top-level adsorption performance with a maximum adsorption capacity of 124 mg/g and a separation factor (βRe/Mo) of 2.78 × 103 for Re. The adsorption capacity per unit area (57.2 mg/(g m2)) is 1.6–41 times higher than previously reported adsorbents, and the cost for adsorbing 1 g of Re (VII) is $1.07, indicating its industrial capability. This adsorption strategy can be applied to separating Re from Mo in binary solutions and industrial wastewater with other competing ions. [ABSTRACT FROM AUTHOR]

Solar‐energy‐driven photoreduction of CO2 is promising in alleviating environment burden, but suffers from low efficiency and over‐reliance on sacrificial agents. Herein, rhenium (Re) is atomically dispersed in In2O3 to fabricate a 2Re‐In2O3 photocatalyst. In sacrificial‐agent‐free photoreduction of CO2 with H2O, 2Re‐In2O3 shows a long‐term stable efficiency which is enhanced by 3.5 times than that of pure In2O3 and is also higher than those on Au‐In2O3, Ag‐In2O3, Cu‐In2O3, Ir‐In2O3, Ru‐In2O3, Rh‐In2O3 and Pt‐In2O3 photocatalysts. Moreover, carbon‐based product of the photoreduction overturns from CO on pure In2O3 to CH3OH on 2Re‐In2O3. Re promotes charge separation, H2O dissociation and CO2 activation, thus enhancing photoreduction efficiency of CO2 on 2Re‐In2O3. During the photoreduction, CO is a key intermediate. CO prefers to desorption rather than hydrogenation on pure In2O3, as CO binds to pure In2O3 very weakly. Re strengthens the interaction of CO with 2Re‐In2O3 by 5.0 times, thus limiting CO desorption but enhancing CO hydrogenation to CH3OH. This could be the origin for photoreduction product overturn from CO on pure In2O3 to CH3OH on 2Re‐In2O3. The present work opens a new way to boost sacrificial‐agent‐free photoreduction of CO2. [ABSTRACT FROM AUTHOR]

The main goal of this work was to elucidate the potential relevance of (radio)metal chelates of 99mTc and Re targeting Gquadruplex structures for the design of new tools for cancer theranostics. 99mTc provides the complexes with the ability to perform single-photon-emission computed tomography imaging studies, while the Re complexes should act as anticancer agents upon interaction with specific G4 DNA or RNA structures present in tumor tissues. Towards this goal, we have developed isostructural 99mTc(I) and Re(I) tricarbonyl complexes anchored by a pyrazolyl-diamine (Pz) chelator carrying a pendant pyridostatin (PDS) fragment as the G4-binding motif. The interaction of the PDF-Pz-Re (8) complex with different G4-forming oligonucleotides was studied by circular dichroism, fluorescence spectroscopy and FRET-melting assays. The results showed that the Re complex retained the ability to bind and stabilize G4-structures from different DNA or RNA sequences, namely those present on the SRC proto-oncogene and telomeric RNA (TERRA sequence). PDF-Pz-Re (8) showed low to moderate cytotoxicity in PC3 and MCF-7 cancer cell lines, as typically observed for G4-binders. Biodistribution studies of the congener PDF-Pz-99mTc (12) in normal mice showed that the complex undergoes a fast blood clearance with a predominant hepatobiliary excretion, pointing also for a high in vitro stability. [ABSTRACT FROM AUTHOR]

Twinning, on par with dislocations, is critically required in plastic deformation of hexagonal close-packed crystals at low temperatures. In contrast to that in cubic-structured crystals, twinning in hexagonal close-packed crystals requires atomic shuffles in addition to shear. Though the twinning shear that is carried by twinning dislocations has been captured for decades, direct experimental observation of the atomic shuffles, especially when the shuffling mode is not unique and does not confine to the plane of shear, remains a formidable challenge to date. Here, by using in-situ transmission electron microscopy, we directly capture the atomic mechanism of the 11 2 ¯ 1 twinning in hexagonal close packed rhenium nanocrystals. Results show that the 11 2 ¯ 1 twinning is dominated by the (b1/2, h1/2) twinning disconnections. In contrast to conventional expectations, the atomic shuffles accompanying the twinning disconnections proceed on alternative basal planes along 1/6 1 1 ¯ 00 , which may be attributed to the free surface in nanocrystal samples, leading to a lack of mirror symmetry across the 11 2 ¯ 1 twin boundary. Atomic shuffles are important phenomena accompanying the twinning in hexagonal close-packed crystals, but the direct experimental observation on it is lacking. Here, the authors show the shuffling mechanism of {112 ̅1} twinning in rhenium nanocrystals by in situ transmission electron microscopy. [ABSTRACT FROM AUTHOR]

The reactivity of [ReOCl3(PPh3)2] towards o‐toluidine, m‐toluidine, o‐fluoroaniline, m‐fluoroaniline, p‐bromoaniline, p‐chloroaniline and p‐anisidine was examined and novel rhenium(V) imido complexes [Re(NC6H4R)Cl3(PPh3)2] (R=o‐Me, m‐Me, o‐F, m‐F, p‐Cl, p‐Br, p‐OMe) were obtained. The resulting products were characterized by elemental analysis, electrospray ionization high‐resolution mass spectrometry (ESI‐HRMS), 1H, 13C{1H}, 19F and 31P{1H} NMR, FT‐IR spectroscopy, and X‐ray crystallography. For m‐toluidine, m‐fluroaniline and p‐chloroaniline, the rhenium(V) imido‐amino mononuclear [Re(NC6H4R)Cl3(H2NC6H4R)(PPh3)] (R=m‐F, p‐Cl) complexes and the binuclear [{Re(m‐NC6H4Me)Cl2(m‐H2NC6H4Me)(PPh3)}2O] complex were isolated as side products and characterized by X‐ray crystallography. All six‐coordinate rhenium(V) complexes display distorted octahedral coordination geometry. [ABSTRACT FROM AUTHOR]

The Re(I) organometallic compounds [(Re(CO)3L1-6)Cl], where ligands L are tryptanthrin derivatives, prepared and characterized by various spectroscopic techniques. To assess the binding capacities and binding manner, tests of calf thymus DNA under the impact of organometallic complexes were conducted using absorption titration and viscosity measuring techniques. Data from the research mentioned above point to an intercalation type of binding, which was verified by the docking study. Swiss ADME tools were used to carry out an ADME study. The work focuses on computing the molecular orbital energies for the synthesized compounds using the density functional theory (DFT). The compounds were tested against the MCF-7 cell line to determine their anticancer effects. It was observed that their IC50 values were equivalent to those of the standard medication, indicating that they had a similar antiproliferative impact. [ABSTRACT FROM AUTHOR]

This is the first comprehensive review of rhenium(I) carbonyl complexes with 2,2′:6′,2″-terpyridine-based ligands (R-terpy)—encompassing their synthesis, molecular features, photophysical behavior, and potential applications. Particular attention has been devoted to demonstrating how the coordination mode of 2,2′:6′,2″-terpyridine (terpy-κ2N and terpy-κ3N), structural modifications of terpy framework (R), and the nature of ancillary ligands (X—mono-negative anion, L—neutral ligand) may tune the photophysical behavior of Re(I) complexes [Re(X/L)(CO)3(R-terpy-κ2N)]0/+ and [Re(X/L)(CO)2(R-terpy-κ3N)]0/+. Our discussion also includes homo- and heteronuclear multicomponent systems with {Re(CO)3(R-terpy-κ2N)} and {Re(CO)2(R-terpy-κ3N)} motifs. The presented structure–property relationships are of high importance for controlling the photoinduced processes in these systems and making further progress in the development of more efficient Re-based luminophores, photosensitizers, and photocatalysts for modern technologies. [ABSTRACT FROM AUTHOR]

Introduction: Hepatocellular carcinoma is a prevalent contributor to global mortality rates. The main palliative treatments are trans-arterial chemoembolization and selective intra-arterial radionuclide therapy. Methods: A novel freeze-dried nonradioactive microsphere kit formulation has been developed, and the behavior and therapeutic potential of 188Re microspheres have been assessed. The microspheres were labeled with fluorescein isothiocyanate (FITC) and 188ReO4−. The uptake of FITC microspheres by HepG2 cells was examined at various time intervals. The impact of 188Re microspheres on cell viability and the mode of cell death were investigated with HepG2 cells using MTT and Annexin FITC-V/propidium iodide (PI) apoptosis assay. Results: The labeling efficiency of microspheres was more than 99% with FITC and 188ReO4−. The maximum uptake of FITC microspheres by HepG2 cells was achieved at 6 h. The exposure to 188Re microspheres has shown a decrease in cellular viability from 77.81% ± 0.015% to 42.03% ± 0.148% at 192 h of incubation (∼11 half-lives). The cellular uptake of 188Re microspheres was 0.255–0.901 MBq. These values were concordant with Annexin FITC-V/PI apoptosis assay. At 192 h, 53.28% ± 0.01% of cells entered the apoptotic phase after treatment with 188Re microspheres, and only 39.34% ± 0.02% of cells remained viable. However, in the cells treated with 188ReO4− alone, 74.86% ± 0.005% of cells were viable, and only 24.75% ± 0.577% of cells were in the early apoptotic phase at 192 h. Conclusion: The data revealed that 188Re microspheres treatment led to significant growth inhibition in HepG2 cells compared with 188ReO4−. [ABSTRACT FROM AUTHOR]

Aiming at the difficulty of extracting and separating of high purity single rare earth elements or compounds, a new emulsion liquid film was constructed and used for the extraction and separation of Re(III) (La3+, Ce3+, Pr3+, Nd3+). The types and concentrations of mobile carriers and surfactants, and the internal water phase in liquid film system were determined by single factor experiment. The results show that the optimal composition of the emulsion liquid membrane system is 6% D2EHPA, 5% T154, 3 mol/L HC1 solution, phase ratio Roi = 1.5. The emulsion film constructed in this system has stable phase and excellent extraction effect, and can realize efficient separation of Re(III). [ABSTRACT FROM AUTHOR]

Interest in covalent enzyme inhibitors as therapeutic agents has seen a recent resurgence. Covalent enzyme inhibitors typically possess an organic functional group that reacts with a key feature of the target enzyme, often a nucleophilic cysteine residue. Herein, the application of small, modular ReV complexes as inorganic cysteine-targeting warheads is described. These metal complexes were found to react with cysteine residues rapidly and selectively. To demonstrate the utility of these ReV complexes, their reactivity with SARS-CoV-2-associated cysteine proteases is presented, including the SARS-CoV-2 main protease and papain-like protease and human enzymes cathepsin B and L. As all of these proteins are cysteine proteases, these enzymes were found to be inhibited by the ReV complexes through the formation of adducts. These findings suggest that these ReV complexes could be used as a new class of warheads for targeting surface accessible cysteine residues in disease-relevant target proteins.

The hot corrosion behaviors of Co–Al–W superalloys with Re additions were investigated at 900 °C. The results showed that the addition of Re improved the hot corrosion resistance significantly. The alloys developed multi-layer oxidation and corrosion products, which located from surface to substrate were: the CoO and Co3O4 layer, the CoWO4 and CoAl2O4 layer, the Al2O3 layer, and the Co3W layer. The addition of Re promotes the formation of the α-Al2O3 scale, which is stable and dense. The thickness the α-Al2O3 scale in 1Re alloy is 1.9 μm, which is much thicker than that of the base alloy. The well-developed α-Al2O3 scale leads to the improvements in hot corrosion resistance.

Tungsten (W) samples containing 0, 1, 3, and 5 at.% rhenium (Re) were irradiated by 20 MeV W ions to 0.5 dpa at 290 K and to 0.3 dpa at 1350 K. An additional set of samples was irradiated to 0.5 dpa at 290 K and then annealed at 1350 K. The irradiated samples were exposed to a deuterium (D) plasma at 370 K. D concentration profiles in the samples were measured using D(He3,p)α nuclear reaction analysis. The D binding states in the defects were analysed using thermal desorption spectroscopy (TDS). In the case of irradiation at 290 K, the trapped D concentration monotonically increases with increasing Re concentration: in W-5%Re it is 17% higher than in pure W. On the contrary, for irradiation at 1350 K the trapped D concentration monotonically decreases with increasing Re concentration: in W-5%Re it is 50 times smaller than in pure W. In the case of annealing at 1350 K of the samples irradiated at 290 K, the Re presence yields only up to three times reduction of trapped D concentration compared with pure W. TDS shows that the nature of D trapping sites is different for the irradiations at 290 K and 1350 K. We attribute the reduced D trapping in W-Re alloys irradiated at 1350 K to the reduction of cavity growth caused by the presence of Re.

Target identification remains a critical challenge in inorganic drug discovery to deconvolute potential polypharmacology. Herein, we describe an improved approach to prioritize candidate protein targets based on a combination of dose-dependent chemoproteomics and treatment effects in living cancer cells for the rhenium tricarbonyl compound TRIP. Chemoproteomics revealed 89 distinct dose-dependent targets with concentrations of competitive saturation between 0.1 and 32 μM despite the broad proteotoxic effects of TRIP. Target-response networks revealed two highly probable targets of which the Fe-S cluster biogenesis factor NUBP2 was competitively saturated by free TRIP at nanomolar concentrations. Importantly, TRIP treatment led to a down-regulation of Fe-S cluster containing proteins and upregulated ferritin. Fe-S cluster depletion was further verified by assessing mitochondrial bioenergetics. Consequently, TRIP emerges as a first-in-class modulator of the scaffold protein NUBP2, which disturbs Fe-S cluster biogenesis at sub-cytotoxic concentrations in ovarian cancer cells.

Although the structural and electrical engineering of transition metal dichalcogenides using atomic doping or doping‐induced phase modulation can be used to attain high‐performance and wavelength‐tunable optoelectronic devices, accessible substitutional doping to overcome the large lattice mismatch between the host and guest atom‐related bonding states remains elusive. This study corroborates an innovative synthetic route for molybdenum disulfide (MoS2)‐derived two‐dimensional (2D) quaternary semiconductors substitutionally doped with Re and O using a solution‐based large‐area compatible approach combined with the thermal evaporation of dopants. The substitutional doping of Re into MoS2 crystals with a large lattice mismatch is effectively accomplished by adopting structurally unstable host films, resulting in the large‐scale synthesis of 2D quaternary multi‐layers with a Re doping concentration >10%. Comprehensive spectroscopic and microscopic evaluations are performed to determine the efficacy of the host films with structural instability for the synthesis of 2D RexMo(1‐x)O2yS2(1‐y) quaternary multi‐layers. The capability of the quaternary semiconductor for versatile nanophotonic devices is validated by ascertaining the simultaneous enhancement of the photoelectrical properties with wide‐range optical absorption and photoelectrochemical properties, as compared with those of their binary counterparts. [ABSTRACT FROM AUTHOR]

Reactions of o‐alkyl naphthol compounds with ReCl3(PMePh2)3 produced naphtho‐rhenafuran complexes, which adapted different ground states (singlet S0 and triplet T0). These polycyclic structures have been characterized experimentally and theoretically. Their electronic behaviors have been studied by UV‐Vis absorption and DFT calculations. [ABSTRACT FROM AUTHOR]

Rhenium is utilized as an additive to improve the high-temperature strength and stability of materials, such as nickel-based superalloys, which are employed in jet engine turbine blades, alloys for ultrahigh-temperature thermocouples, and platinum catalysts, which are used in oil refining. Currently, around 80% of rhenium demand is for superalloy production, and this demand has been increasing with the increase in demand for aircrafts. The abundance of rhenium in the earth's crust is only 1 ppb (10−9), which is less than those of platinum and gold. Owing to the rare and unevenly distributed nature of rhenium, there is the risk of supply disruption and rapid increases in its price. In this article, the recent situation of rhenium and its compounds are reviewed, especially with respect to their demand, distribution characteristics, smelting, and recycling. Some of the technologies recently developed for smelting and recycling rhenium are also introduced. [ABSTRACT FROM AUTHOR]

Due to their favorable chemical features, Re and Tc complexes have been widely used for the development of new therapeutic agents and imaging probes to solve problems of biomedical relevance. This review provides an update of the most relevant research efforts towards the development of novel cancer theranostic agents using Re and Tc‐based compounds interacting with specific DNA structures. This includes a variety of homometallic complexes, namely those containing M(CO)3 (M=Re, Tc) moieties, that exhibit different modes of interaction with DNA, such as covalent binding, intercalation, groove binding or G‐quadruplex DNA binding. Additionally, heterometallic complexes, designed to potentiate synergistic effects of different metal centers to improve DNA‐targeting, cytotoxicity and fluorescence properties, are also reviewed. Particular attention is also given to 99mTc‐ and 188Re‐labeled oligonucleotides that have been widely explored to develop imaging and therapeutic radiopharmaceuticals through the in vivo hybridization with a specific complementary DNA or RNA target sequence to provide useful molecular tools in precision medicine for cancer diagnosis and treatment. Finally, the need for further improvement of DNA‐targeted Re and Tc‐based compounds as potential therapeutic and diagnostic agents is highlighted, and future directions are discussed. [ABSTRACT FROM AUTHOR]

Background. At Almalyk MMC JSC, produces a stub of molybdenum industrial product, while sublimated rhenium semioxide is absorbed, perrenate ions from the technological solution are adsorbed, the sorption process is inhibited by organic contamination of the solution.. Purpose: to develop and test a method without permanganate oxidation of organic compounds in a rhenium-containing production solution. Methodology. Process solutions were monitored by elemental analysis (Agilent 7500 IСP-MS), X-ray fluorescence (Rigaku NEXCGEDXRFAnalyzer), IR spectroscopic (PYE NiCAM and IR-Fourier Nicolet iS50, ThermoScientific, 700-3600 cm-1). Originality. The possibility of using ozonation for the destruction of organic compounds in a process solution is substantiated. Findings. IR spectra of solutions, the values of their redox potentials, and data on the destruction of impurities by the ozonation method were obtained. [ABSTRACT FROM AUTHOR]

The oxidative weathering of petrogenic organic carbon (OCpetro) is an important source of carbon dioxide (CO2) into the atmosphere on geological timescales and significantly influences the carbon cycle and global climate change. However, at present, a robust proxy to assess OCpetro oxidation is lacking. Riverine rhenium (Re) has emerged as a potential proxy to trace OCpetro oxidation, but little is known about Re sources and its relationship with OCpetro oxidation. To better understand the robustness of this proxy, we analyzed a shale weathering profile from the early Cambrian Shuijingtuo Formation in Chengkou County, Chongqing City, to address the mobility of Re and selenium (Se) and their relationship with the oxidation of OCpetro by analyses of the elemental variation and sequential extraction. The results showed that the chemical index of alteration (CIA) increases from the fresh bedrock to the weathered sections, indicating enhanced weathering intensity. Based on the sequential extraction and mass transfer coefficients (τ), Re and Se mainly exist in the organic phase of shale and are paired lost with OCpetro during weathering, with no obvious correlation with sulfide minerals. Furthermore, the different proportions of Re and Se loss with OCpetro loss can be attributed to their different geochemical behaviors during weathering. Our study supports Re as a robust proxy to trace OCpetro oxidation, whereas Se is the potential one. In the future, combined studies on various sedimentary rock profiles with catchment basins are needed to determine the sources of riverine Re and Se and their relationships with OCpetro oxidation. [ABSTRACT FROM AUTHOR]

Using a one-pot cyclo-condensation process under microwave irradiation, derivatives of curcumin have been created. Evaluation their anti-inflammatory efficacy showed that they had stronger properties than curcumin. Additionally, the most active derivative was radiolabeled with the diagnostic radioisotope technetium-99m and prepared with a high radiochemical yield (96.5 ± 0.09%) and in vitro stability of up to 6 h. The in-vivo study in inflamed mice showed that [99mTc]Tc-curcumin derivative accumulated with a high target to non-target ratio. The gathered information confirmed the efficacy of the [99mTc]Tc-curcumin derivative as a novel possible tracer for the identification and localization of inflammation. [ABSTRACT FROM AUTHOR]

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Morpholine motifs have been used extensively as targeting moieties for lysosomes, primarily in fluorescence imaging agents. Traditionally these imaging agents are based on organic molecules which have several shortcomings including small Stokes shifts, short emission lifetimes, and susceptibility to photobleaching. To explore alternative lysosome targeting imaging agents we have used a rhenium based phosphorescent platform which has been previously demonstrated to have an improved Stokes shift, a long lifetime emission, and is highly photostable. Rhenium complexes containing morpholine substituted ligands were designed to accumulate in acidic compartments. Two of the three complexes prepared exhibited bright emission in cells, when incubated at low concentrations (20 μM) and were non-toxic at concentrations as high as 100 μM, making them suitable for live cell imaging. We show that the rhenium complexes are amenable to chemical modification and that the morpholine targeted derivatives can be used for live cell confocal fluorescence imaging of endosomes–lysosomes. [ABSTRACT FROM AUTHOR]