Discovery, crystal structure, anticancer property of the first-row transition metal complexes of norcantharidin (NCTD) as potential inducer of mitochondrial damage.

Dynamic ion gels (DIGs) obtained via complex coacervation of oppositely charged poly(ionic liquid)s (PILs) address the inherent trade-off between ionic conductivity (σDC) and mechanical strength (G′) of PILs by providing both enhanced ion transport and robust viscoelastic properties. In order to tune the strength of ionic cross-links through charge delocalization of ion pairs, we study a series of four DIGs obtained from the combination of a cationic PIL (PIL+) containing pendant imidazolium groups and free bis(trifluoromethylsulfonyl)imide (TFSI) counteranions with four anionic PILs (PIL–) bearing pendant sulfonate anions and various free counter cations (i.e., 1-methyl-3-butylimidazolium, trimethylpropylammonium, tetrabutylammonium, and tetrabutylphosphonium). These new DIGs are produced via the formation of ionic cross-links with ion pairs having more localized charges (i.e., cations paired with sulfonate instead of TFSI). This results in stronger electrostatic interactions with counterions, reducing their mobility and significantly increasing the enthalpic driving force for ion exchange-induced coacervation. As a consequence, the four resulting DIGs release different free ionic liquids (ILs) consisting of TFSI anions associated with imidazolium, ammonium or phosphonium cations. The physical, ion-conducting, and viscoelastic properties of the resulting DIGs are systematically investigated by differential scanning calorimetry, broadband dielectric spectroscopy and rheology. The DIG having sulfonate-imidazolium ionic cross-links and releasing EMIM-TFSI ILs exhibits the best compromise between G′ = 62 kPa (at 25 °C, 1 rad s–1) and σDC = 6.5 × 10–6 S cm–1 (at 25 °C), significantly outperforming the parent PILs. These results highlight DIGs as a highly promising class of materials with enhanced processability and mechanical integrity, making them ideal candidates for electrochemical applications such as supercapacitors, soft robotics, electrochromic devices, sensors, and solar cells.

Manipulating the organic counter cations, which serve as pore gatekeepers to selectively obstruct the channels in anionic metal-organic frameworks (MOFs), offers a highly effective strategy for optimizing the separation performance. Here, we report an yttrium-based MOF, Y-ebdc, featuring cage-type structures that accommodate protonated dimethylamine (DMA) as both counter cations and molecular sieving gates. Subsequent optimization of the adsorption separation performance for propylene/propane (C₃H₆/C₃H₈) was achieved through regulation of DMA’s thermal decomposition. The temperature dependence of DMA decomposition was elucidated using temperature-resolved in situ infrared spectroscopy and breakthrough studies. With approximately 70% of DMA removed, the expanded aperture window and increased pore volume remarkably enhance dynamic C₃H₆ uptake while simultaneously facilitating the direct production of polymer-grade (>99.5%) C₃H₆ in a single adsorption–desorption cycle. This study exemplifies how engineering the pore environment via co-existing counter cations within MOFs can effectively boost gas adsorption and separation performance.

A strategy focusing on framework stability and proton-conducting hydrogen-bonding networks in polyoxoniobates (PONbs) has been implemented, wherein protonated organic amines act as exclusive counter cations, synergistically enhanced by embedded 4p-4f metal-oxo clusters. This approach yields a new family of three-dimensional (3D) supramolecular frameworks, H6(CN3H6)8[As4Ln4O12(H2O)4(CO3)4(Nb5O14)2]·34H2O (1-Ln, Ln = Sm, Eu, Tb, Dy, Ho, Er, Yb), representing the first reported PONbs featuring a "double-tetrahedral, coaxially nested" 4p-4f metal-oxo cluster (As4Ln4). Impedance measurements show that 1-Eu exhibits a proton conductivity of 1.21 × 10-2 S·cm-1 at 85 °C and 98% RH. Water vapor adsorption reaches saturation at P/P0 = 0.946 with a maximum uptake of 296.6 cm3·g-1. In addition, 1-Eu and 1-Tb display characteristic lanthanide-centered luminescence.

Herein, two distinct crystals from the same precursors by modulating the solvent ratio in solvothermal reactions were successfully obtained. Comprehensive characterization, including single-crystal X-ray diffraction, solid-state UV-vis-NIR diffuse reflectance spectroscopy, electron paramagnetic resonance, powder X-ray diffraction (PXRD), and theoretical calculations, provided deep insight into the material's unique structure and electronic characteristics. The results revealed that Crystal 1 exhibits a unique structure comprising alternating metal-oxo clusters and organic linkers, reinforced by strong lone pair-π interactions and a hydrogen-bonding network involving dimethylammonium cations. These structural features endow this crystalline material with broad-range absorption (200-850 nm) and a narrow bandgap (as small as 1.55 eV). Remarkably, Crystal 1 enables efficient and reversible switching between black and yellow states through alternating ozone oxidation and photoinduced stimulation, while fully maintaining the integrity of its crystal structure. In contrast, Crystal 2, which lacks such structural motifs, counter cations, and strong intermolecular interactions, shows only narrow and weak absorption with essentially no color change under photoinduction. This work highlights the critical role of targeted intermolecular interactions in directing structure assembly and tuning optoelectronic properties, providing a strategic guideline for the design of intelligent optoelectronic materials.

In alkali metal thallides, a huge variety of thallium clusters can be realized, which are surrounded only by alkali metals. In most cases, different cluster types are present in the crystal structures at the same time. One example is the [Tl5]7- trigonal bipyramid, which has only been observed beside [Tl9]9-, [Tl4]8-, [Tl3]7-, [Tl]5-, or [Tl8Cd3]10-. In the new ternary alkali metal thallide phase K7-xAxTl5 (A=Rb, Cs; 0<x≤2.35), exclusively [Tl5]7- clusters are present, and the compound can be described as a salt-like Zintl-phase, where the electron count is balanced in terms of the anionic moiety and counter cations. This phase crystallizes in the orthorhombic noncentrosymmetric space group Ama2. Different temperature programs applied during synthesis suggested metastability, which was subsequently proven by DSC measurements. DFT calculations reveal a minimum in the DOS at EF and support the salt-like description. Dissolution experiments in the style of well-known group 14 and group 15 solution chemistry in liquid ammonia were performed and showed oxidation of the alkali metal thallide. Initial 205Tl NMR studies in liquid ammonia allow for the detection of the first signal of a dissolved thallium species emerging from a thallide Zintl phase.

Electrochemical CO2 reduction (CO2RR) is gaining traction as an avenue to synthesize value-added products, such as ethanol and formic acid, directly from air and CO2-rich gas effluents. However, the current focus centers upon creating catalysts with high activity and product selectivity with lesser regard to long-term stability. Significant changes to both catalyst structure and content (material stability) and current/potential (electrochemical stability) determine a catalyst’s viability toward practical implementation.1-3 Silver and bismuth catalysts demonstrate high selectivity toward carbon monoxide and formate/formic acid, respectively, prompting the need for stability assessments beyond post-mortem characterization.Here, using a stationary probe rotating disk electrode paired with inductively coupled plasma mass spectrometry (SPRDE ICP-MS), we evaluate both potential- and time-resolved metal dissolution of Ag- and Bi-based electrodes during CO2RR. We investigate the effect of electrolyte composition, including pH and counter cation (Li+, Na+, K+), on both dissolution and catalytic performance. We further address the issue of metal impurities such as Fe2+ and Zn2+ on accelerating catalyst deactivation. Corresponding in situ Raman analysis reveals the intermediate formation pathways, enabling the relation of the CO2RR mechanism with stability profiles to connect electrochemical and material stability events. Overall, we demonstrate the delicate balance of activity, selectivity, and stability, that must be achieved for robust catalytic systems targeting CO2RR. Acknowledgements: The research was conducted at Argonne National Laboratory, a U.S. Department of Energy Office of Science laboratory, operated by UChicago Argonne, LLC under Contract no. DE-AC02-06CH11357. The authors acknowledge the support from the Department of Energy, Energy Efficiency and Renewable Energy, Bio Energy Technologies Office, CO2RUe Consortia. The submitted abstract has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory (“Argonne”). Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357. The U.S. Government retains for itself, and others acting on its behalf, a paid-up nonexclusive, irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan. http://energy.gov/downloads/doe-public-access-planReferences. Lopes, P. P., A Framework for the Relationships between Stability and Functional Properties of Electrochemical Energy Materials. ACS Mater. Au 2023, 3 (1), 8-17.Rigby, K.; Kim, J.-H., Deciphering the issue of single-atom catalyst stability. Curr. Opin. Chem. Eng. 2023, 40, 100921.Rigby, K.; Huang, D.; Leshchev, D.; Lim, H. J.; Choi, H.; Meese, A. F.; Weon, S.; Stavitski, E.; Kim, J.-H., Palladium Single-Atom (In)Stability Under Aqueous Reductive Conditions. Environ. Sci. Technol. 2023, 57 (36), 13681-13690.

For many years, phosphors have been proposed as the active element for smart sensors to monitor surface temperature, particle impacts, and ionizing radiation in space. Research has shown that proton bombardment in the keV to MeV range, like that occurring in space, reduces the intensity of fluorescence. Over the last quarter of a century, the authors have measured the emission yield for a variety of luminescent materials, including ZnS:Mn and EuD4TEA. Both phosphors emit copious TL when struck. In addition, EuD4TEA is more easily damaged by radiation compared to ZnS:Mn. Coupled together, this makes EuD4TEA a good smart sensor material for space applications. According to Tribble, a spacecraft at 1 AU from the sun will receive a 1 MeV proton fluence of less than about 1011 mm-2 from a large solar event. Likewise, 1 MeV proton fluences in the Earth’s radiation belts and the Earth-Moon-Sun Lagrange points will be even less than the 1011 mm-2 value from large solar events. For that reason, EuD4TEA should be a good candidate for use as a proton fluence sensor for spacecraft.Some time ago, the Cajun Advanced Picosatellite Experiment (CAPE) program at the University of Louisiana at Lafayette began developing student-built satellite projects for launch into space. In January 2021, the CAPE-3 CubeSat was launched to measure proton fluence in space using EuD4TEA. The Astronaut-Wearable Radiation Meter for Operation in Potential Radiation Environments (ARMOR) payload was an integral part of the 1U CAPE-3 CubeSat. For a variety of reasons, no radiation exposure data was returned to Earth from CAPE-3. It was decided to re-design and build an improved ARMOR payload to fly on the upcoming CAPE-4 CubeSat, which should be launched in 2026. The larger 3U CAPE-4 satellite will use multiple EuD4TEA samples positioned in different spatial orientations and with varying amounts of absorber materials.Mech et al. have shown that when EuD4 - is provided with a sufficiently large counter cation, a change occurs in the luminescence. The time-resolved emissions are best fit by two exponentials, and at 77 K they were able to resolve two peaks with less than 1 nm separation. Previous work by Fontenot et al. was done to investigate the effect of adding water to the synthesis of EuD4TEA. One of these water-doped samples was investigated using the Emerging Measurements Company’s Thermographic Phosphor LabKit to see if TEA+ is sufficiently large to produce results similar to those reported by Mech et al. The temperature dependent spectra and time-resolved emissions were captured by an Ocean Optics S2000 spectrometer, and the LabKit’s standard Hamamatsu H10721-110 PMT, respectively. The collected signals were processed by custom MATLAB® code.

Charged polymer membranes are of great interest in various applications, ranging from environment, energy, and health. Understanding of ion transport in charged polymer membranes is critical to the advancement of technologies related to polymer electrolytes in batteries and fuel cells, water purification, critical element extraction, environmental remediation, and medical isotope purification. Here, we designed a systematic library of weak polyelectrolyte membranes based on polyacrylic acid (PAA). A series of polyacrylic acid (PAA) based polymer networks were synthesized with varied charged group contents and controlled water swelling. By adjusting external pH, the number of sodium counter cations dissociated and condensed on the polymer backbone can be systematically changed, leading to different ion transport and dielectric properties in the polymers. We evaluated ion and water transport properties (solubility, diffusivity, and permeability) in the resultant polymer membranes. These transport properties are correlated with dielectric properties in the polymers via dielectric relaxation spectroscopy (DRS). This model system enables us to elucidate the mechanism of ion transport in charged polymer membranes.

Alkynylation of isatins with calcium carbide (CaC 2 ) in solution has been reported to selectively yield mono‐alkynylation products (i.e., 3‐ethynyl‐3‐hydroxy‐2‐oxindoles). In this work, we studied the reaction under mechanochemical conditions, finding that upon ball milling, the acetylenic anions [C 2 ] 2– present in CaC 2 react with isatin, leading preferentially to the bis ‐alkynylation addition product [i.e., 3‐ethynyl‐ bis (3‐hydroxy‐2‐oxindole)]. Through experimental work and computational mechanistic studies within the framework of density functional theory, we investigated the change in selectivity and identified i) the highly concentrated reaction environment under ball milling and ii) the avoidance of bulk water as conditions that favor the bis ‐alkynylation of two isatin molecules with a single [C 2 ] 2– fragment. In addition, we found that the reaction occurs through several variants of the same overall mechanism, in which some cationic metal counterions play a relevant role through noncovalent interactions.

Anatase‐supported vanadium‐substituted Keggin‐type polyoxometalates (POMs) are promising alternative catalysts for the selective catalytic reduction (SCR) of NOx with NH3 at low temperatures. Generally, alkali poisoning is a major deactivation mechanism in vanadium‐catalyzed SCR, but changing the counter cations in the POM catalyst might be a propitious strategy for enhancing the catalyst stability. In this study, the effect and the role of cation variation were investigated in detail by exchanging the protons from the most promising Keggin‐type HPA‐3 (H6PV3Mo9O40) catalyst dispersed on anatase support with cations such as Na+, K+, Cs+. The synthesized catalysts were characterized in‐depth using ICP‐OES/AAS, FTIR, TGA, NH3‐TPD, EPR, H2‐TPR, ED (electron diffraction) and XPS. The supported HPA‐3/TiO2 catalyst with a 7.5 wt. % loading was found to be the most active catalyst for the SCR reaction in the temperature range of 200–300 °C, providing nearly complete NO conversion at 300 °C with a relatively high first‐order rate constant. In comparison, the analogous alkali‐exchanged catalysts possessed lower activities, which by characterization was corroborated to a combined effect of lower acidity and altered redox property. The study reveals new insight into NH3‐SCR catalysts comprising redox‐active POMs, which so far mainly have been applied for homogeneously catalyzed reactions.

Deciphering the role of non-covalent interactions in CO2 Capture: A DFT and COSMO-RS study of amino acid-based ionic liquids.

Two new Cr(III) complexes of pyridine-2,6-dicarboxylato(2-) ligands with pyridinium type counter cations: Synthesis, structures, thermal behavior, Hirshfeld surface analysis and antibacterial activities

ABSTRACTThis study utilizes the homopolymer, poly(sodium 2‐acrylamido‐2‐methylpropanesulfonate) (PAMPSNa90) to synthesize the thermo‐responsive ionic liquid polymer P[AMPS][P4448]90 by exchanging the counter cation, sodium (Na+) of 2‐acrylamido‐2‐methylpropanesulfonic acid (AMPS) with tributyl(octyl)phosphonium bromide ([P4448+]Br). Furthermore, a two‐step synthesis approach was employed to create a dual thermo‐responsive water‐soluble diblock copolymer PAMPSNa90‐b‐PNIPAM279 composed of PAMPSNa90 and poly(N‐isopropylacrylamide) (PNIPAM) via reversible addition‐fragmentation chain transfer polymerization. Later a modification was carried out to exchange the counter cation Na+ in PAMPSNa90‐b‐PNIPAM279 with [P4448+], resulting in the P[AMPS][P4448]90‐b‐PNIPAM279. The individual synthesized polymers were extensively characterized using proton nuclear magnetic resonance spectroscopy and gel permeation chromatography to infer their correct synthesis composition and molecular weight. Turbidity, measured by the percentage transmittance, revealed the thermo‐responsive behavior of these synthesized blocks. The hysteresis phenomenon of heating/cooling for each synthesized polymer was identified as single or dual cloud point temperature, depending on the applied stimuli such as polymer concentration, temperature rate, and sonication. Scattering techniques, such as dynamic light scattering and small‐angle neutron scattering, were employed to obtain insight into the size/shape of the self‐aggregates formed in an aqueous solution environment, which is supported using transmission electron microscopy.

A new heterometallic heptanuclear oxalato-bridged [K4ICr3III] complex with pyridinium type counter cations: Synthesis, crystal structure, thermal behavior, magnetism and antibacterial activities

Polyoxometalates (POM) are promising materials for electrochemical applications, such as supercapacitors. However, their stability in aqueous electrolytes is compromised due to POM cluster leaching. To mitigate this issue, POM can be combined with organic counter cations, which reduce their solubility in water and influence interactions with carbon support materials. Nevertheless, further research is needed to determine the optimal characteristics and electrode design for maximizing performance. In this work, a synergistic methodology to investigate POM compounds bearing cations with three core functionalities (ammonium, imidazolium, and pyridinium) and varying alkyl side chain lengths, is developed in order to elucidate and optimize the effects of hydrophobicity on the structure of organic–inorganic hybrid materials, electrode films, and their electrochemical performance. The results show that, although cations with long alkyl chains exhibit lower capacitance, they can be activated through molecular rearrangement in the solid state, facilitated by the flexibility of these chains within the structure. By combining thermal and electrochemical techniques, the electrode materials are optimized. These findings demonstrate that the careful selection of counter‐cations with the appropriate molecular structures, followed by a thermal activation protocol, is key to developing more efficient and durable energy storage systems.

Abstract Low‐dimensional hybrid halide perovskites (LDHPs) have attracted intensive attention in X‐ray detectors. However, they are still limited by their poor charge transfer capacity between organic and inorganic layers. And, the impact of the soft lattice variability characteristics on device performance is still unclear. Here, this study constructs a novel N, N‐Dimethylaminomethylferrocene (MAFc)‐based one‐dimensional (1D) perovskite single crystal, (MAFcH)PbI 3 •DMF (DMF = N, N‐Dimethylformamide), in which the protonated MAFcH can not only act as counter cations, but also as carriers’ transfer media to promote charge carriers’ transport. Significantly, (MAFcH)PbI 3 •DMF single crystal can be transformed into (MAFcH)PbI 3 single crystal through the loss of DMF. Notably, by controlling lattice contraction through the heating method, the (MAFcH)PbI 3 •DMF single crystal (13.1%) in the fabricated (MAFcH)PbI 3 •DMF (13.1%)/(MAFcH)PbI 3 single crystal device can promote effective separation and extraction of X‐ray induced charge carriers. The fabricated (MAFcH)PbI 3 •DMF (13.1%)/(MAFcH)PbI 3 single crystal device exhibits an excellent response to hard X‐rays (120 kV), and yields a high sensitivity of 1.7 × 10 4 µC Gy air −1 cm −2 with the lowest detectable X‐ray dose rate of 120 nGy air s −1 . Moreover, the fabricated X‐ray detector shows excellent long‐term X‐ray operational stability with no attenuation observed after 6 months of exposure to air without encapsulation.

N-type polymer poly(benzodifurandione) (PBFDO) has demonstrated record-high conductivity in its highly doped state; however, various applications require optimized rather than maximized doping levels. Herein, we systematically investigate the relationship between doping level and charge transport properties in PBFDO using electrochemical dedoping to precisely control doping states, coupled with Hall effect measurements to directly characterize the carrier concentration and mobility. During the dedoping process, both carrier concentration and mobility simultaneously decrease from 2.03E22 to 7.85E21 cm-3 and from 0.40 to 0.16 cm2 V-1 s-1, respectively, with conductivity reducing from 1286 to 206 S cm-1. Spectroelectrochemical analysis reveals characteristic absorption changes during dedoping, while EPR analysis revealed a transition from polaron pairs to single polarons during dedoping. GIWAXS further demonstrated that dedoping led to an increased interlayer spacing and structural disorder, consistent with a reduced mobility. Unlike conventional conjugated polymers, PBFDO's unique behavior derives from its unique in situ n-doping process and the incorporation of protons acting as counter cations. This study provides critical insights for tailoring PBFDO's electronic properties across different doping regimes for diverse applications.

Hydride transfer is an essential elementary reaction across the chemical value chain, but there are limited methods available for quantifying thermodynamic hydricity (ΔGH−), particularly amongst main group reagents. Herein, we exploit facile H2 activation and reversible hydride transfer from a metal surface to a molecular reagent, the net hydrogen reduction reaction (HRR), to develop a potentiometric method for quantifying ΔGH− of main group reagents recalcitrant to conventional methods. HRR potentiometry is first validated with a benzimidazolium hydride donor and then applied to uncover the impact of the reaction environment on hydricity. Across benzimidazolium hydride donors, HRR equilibrium potentials are roughly invariant across solvents, indicating that the solvent dependence of its hydricity largely reflects the differential solvation of H− across media. For formate, HRR potentials and corresponding hydricities depend strongly on water content. For borohydrides, HRR potentiometry reveals that effective hydricity values are strongly influenced by Lewis acid-base adduct formation with the hydride acceptor but are minimally influenced by the counter cation. These studies highlight the power of HRR potentiometry to both quantify and uncover trends in hydricity across main group reagents.

Cellulose, a pivotal component of plant cell walls, is a widely studied biologically derived material with vast potential for numerous applications. However, visualizing the arrangement of individual cellulose molecules within hierarchical structures with electron microscopy has proven challenging due to the material's low contrast and high beam sensitivity. In this study, a novel approach is introduced that combines labeling of cellulose functional groups with high‐contrast cesium counter cations (Cs+) in conjunction with atomic resolution scanning transmission electron microscopy (STEM) in annular dark‐field (ADF) mode at cryogenic temperatures. This technique allows for the identification of individual sulfate groups attached to cellulose chains within cellulose nanocrystal hierarchies at Ångström resolution. Systematic comparison of experimentally obtained interatomic Cs+ distances with simulations potentially enables the localization of the labeled functional groups at the macromolecular level. The method has the potential to elucidate the polymer chain arrangements in nanoscale soft materials.