Search Results (440)

Ten compounds have been prepared among them six different dioxido(pyridine-2,6-dicarboxylato)vanadate(V) compounds with piperazinium (H₂pip²⁺) (1·6H₂O), methylpiperazinium (H₂mepip²⁺) (2·5H₂O), ethylpiperazinium (H₂etpip²⁺) (3·3H₂O), isopropylpiperazinium (H₂isopip²⁺) (4·H₂O), phenylpiperazinium (Hphepip⁺) (5∙H₂O) and thiomorpholinium 1-oxide (HtmorO⁺) (6·2,6-H₂pydc·2H₂O) cations as counterions as well as methylpiperazinium (H₂mepip²⁺) salt of a mixed valence vanadium [VO(2,6-pydc)-(μ-O)-VO(H₂O)(2,6-pydc)]⁻ complex (7), thiomorpholin-4-ium vanadate (Htmor)VO₃ (8), hexa(thiomorpholin-4-ium) decavanadate hexahydrate (Htmor)₆[V₁₀O₂₈]·6H₂O (9·6H₂O) and organic salt cocrystal thiomorpholin-4-ium 6-carboxypicolinate pyridine-2,6-dicarboxylic acid (Htmor)⁺(2,6-Hpydc)⁻∙(2,6-H₂pydc)·2H₂O (10·2H₂O) via different pathways starting either from pyridine-2,6-dicarboxylic acid or its esters, and were structurally characterized by single-crystal X-ray diffraction. Extended hydrogen bonding interactions are present due to the presence of organic cations as well as due to the diverse roles of water molecules in the hydrogen bonding network. Centrosymmetric hydrogen bonding was found to be an important motif, and diverse supramolecular patterns were also observed due to a wide variety of C–H···O and π···π interactions stabilizing the crystal lattices. Full article

Volatile amphiphiles and surfactant mixtures have gained wide applications in diverse areas of industry, cosmetics, and medicine. The surface tension isotherms, measured at different solute ratios, and data processing, using appropriate theoretical models, provide quantitative information on their bulk and interfacial properties. Here, this approach is applied for mixtures of volatile amphiphile (benzyl acetate, linalool, geraniol, menthol, citronellol) and sodium dodecyl sulfate (SDS). All surface tension isotherms are described by the van der Waals model for a two-component adsorption layer, taking into account the counterion binding in the Stern layer, by varying only one adjustable parameter (interfacial pair interaction energy between adsorbed molecules). Knowing the parameters of the model, we computed various properties of the adsorption layers (adsorptions of different components, occupancy of the Stern layer, and interfacial electrostatic potential). The experimental aqueous solubilities of mixtures are fitted using the regular solution theory to obtain the pair bulk interaction parameter. The mixing of SDS and: (i) benzyl acetate and citronellol is antagonistic; (ii) linalool and geraniol is synergistic; and (iii) menthol is ideal. The reported properties of the volatile amphiphiles and SDS mixtures could be of interest for increasing the range of their applicability in practice. Full article

Highly polar M-mol-X (M = alkali metal, mol = molecule, X = halogen) insertion complexes have been predicted to offer potential practical applications, including molecular interactions with light, ion-pair induced isomerization, etc. In the present work, the insertion complexes of the seven-membered, fused bicyclic norcaradiene and its monocyclic isomer trapped in Li-I, Na-I, and K-I counterion pairs were investigated using ab initio methods. The structures, stability, polarities, and simulated infrared spectra are analyzed and the effects of the insertion on the norcaradiene to cycloheptatriene isomerization process are examined. Furthermore, an uncommon bond between iodine and a fully substituted carbon atom is reported upon and hypothesized to be catalyzed by the presence of the cation in the insertion complexes. Full article

Carnosine (or β-alanyl-L-histidine) is an endogenous compound playing very important roles in human organisms as antiglycation and antioxidant agents, and, in addition, helping to mitigate illnesses such as cancer and neurodegenerative diseases. Aiming to explore the chelating ability of carnosine, based on its coordinating possibilities, we started to investigate the metal complexes of essential copper(II), zinc(II), and iron(II) ions coordinated to this dipeptide. Different compounds were isolated in the solid state by adding stoichiometric amounts of metal salts to carnosine at controlled pH or under a controlled atmosphere, with the formation of mono-, bi- and polynuclear species. These complexes were subsequently characterized mainly by spectroscopic techniques (UV–Vis, IR, EPR), in addition to elemental analysis. A binuclear species was isolated with copper(II) and had its structure determined by X-ray diffraction, improving previously reported data in the literature. Two insoluble correlated trinuclear species were isolated with zinc(II) ions, using perchlorate or chloride as counter-ions. In the case of iron, a mononuclear species was verified with Fe(II) ions, obtained under an inert atmosphere. Further, the antioxidant properties of free carnosine and the copper–carnosine complex were verified by their scavenging activity toward the ABTS^•+ radical, using Trolox as a reference, showing significant activity. The carnosine–metal complexes were also tested as potential antineoplastic agents, in comparison to the free ligand, after 24 h of incubation at 37 °C, using malignant HeLa, SKMEL 28 and SKMEL 147, and non-tumor fibroblast cells. Results indicated neglected or poor anti-proliferative properties of these metal complexes, when compared to other similar compounds described in the literature. Full article

Long-chain aldehydes, particularly nonanal, are recognized as potential volatile biomarkers of lung cancer in exhaled breath. This study investigates the influence of peptide counter-ions on the performance of QCM-based biosensors using two odorant-binding protein-derived peptides (OBPP4 and OBPP4 GSGSGS) for the selective gas-phase detection of these aldehydes. Exchanging the counter-ion from trifluoroacetate to chloride improves biosensor sensitivity and lowers the limit of detection within the set of biosensors investigated in this study. The OBPP4 GSGSGS with chloride exhibited the highest sensitivity to nonanal (0.153 Hz/ppm) and the lowest LOD (9.8 ppm), with excellent selectivity over other groups of volatiles. The novelty of this work lies in demonstrating, for the first time, that simple counter-ion exchange in synthetic peptides can significantly enhance the gas-phase binding of volatile aldehydes, classified as lung cancer biomarkers, without altering the peptide sequence, offering a straightforward and effective optimization strategy for peptide-based piezoelectric biosensors. Full article

The crystal structures of the cobalt(II) metal–organic frameworks or coordination networks of [Co(pdb)(DMF)] and [Co₂(pdi)(DMF)₃]·2(DMF)·H₂O (H₂pdb = 3,3′-(phenazine-5,10-diyl)dibenzoic acid; H₄pdi = 5,5′-(phenazine-5,10-diyl)diisophthalic acid; DMF = N,N-dimethylformamide) were synthesized solvothermally from cobalt(II) nitrate and the free acid of the linker in DMF. Systematic solvothermal screening demonstrated strong metal- and counterion-dependent framework formation, as crystalline coordination polymers were obtained exclusively from cobalt(II) nitrate, whereas other metal salts and cobalt(II) chloride or sulfate produced no crystalline materials. In catena-[(N,N-dimethylformamide)-μ₄-3,3′-(phenazine-5,10-diyl)dibenzoate-cobalt(II)], [Co(pdb)(DMF)], the Co₂ units, acting as secondary building units, are coordinated by four carboxylate groups from four linkers in a paddle-wheel arrangement, giving a three-dimensional (3D) network with cds (or CdSO₄) topology, in which the wide openings are filled by two symmetry-related nets to form a threefold interpenetrated structure. In catena-[tris(N,N-dimethylformamide)-μ₈-5,5′-(phenazine-5,10-diyl)diisophthalate-dicobalt(II)] bis(N,N-dimethylformamide) hydrate, [Co₂(pdi)(DMF)₃]·2(DMF)·H₂O, there are two different Co atoms, of which only Co₂ is connected to each of the four carboxylate groups of the tetracarboxylate linker and, thus, is responsible for 3D network formation. The network topology in [Co₂(pdi)(DMF)₃] is pts (or platinum(II) sulfide) when taking the Co₂ atom as a tetrahedral node and the linker as a square-planar fourfold node; however, this arrangement is inverse to the common square-planar metal and tetrahedral linker nodes found in PtS and most pts topologies. Full article

The persistence of per- and polyfluoroalkyl substances (PFASs) poses a significant challenge in solid waste management. This paper systematically reviews the distribution characteristics of PFASs in various solid waste streams, including industrial sludge, food packaging, textiles, and electronic waste. It also evaluates the removal efficiency of four thermal treatment technologies—incineration, pyrolysis, smoldering combustion, and hydrothermal liquefaction (HTL)—for PFASs in solid waste. Although incineration and smoldering combustion can achieve destruction and removal efficiencies exceeding 99.99%, the release of short-chain byproducts remains a critical bottleneck. Pyrolysis effectively decontaminates solid-phase products but carries the risk of phase transfer into pyrolysis oils. The efficiency of HTL is highly dependent on process parameters. PFAS degradation is a radical-mediated process initiated by the dissociation of functional groups. We emphasize that substrate surface properties and the presence of counterions play pivotal roles in modulating these reaction pathways. The introduction of water vapor (as a hydrogen-rich medium), alkaline additives, or specific catalysts is considered a promising strategy to inhibit the recombination of reactive byproducts and enhance mineralization rates. Full article

Organic mixed ionic–electronic conductors (OMIECs) are pivotal for bioelectronics; however, the microscopic origins of doping-dependent charge transport remain elusive. In this study, we established a multi-scale computational framework to quantify the distinct intramolecular electronic coupling ($H_{ab}$) distributions in systems with 25% and 75% doping levels. Our protocol employs automated quantum chemical calculations to exhaustively identify intrinsic local minima, ensuring thermodynamically stable initial conformations. Subsequent Molecular Dynamics (MD) simulations characterize the equilibration timescales and counter-ion dispersion behaviors. The simulation results reveal that the 75% doped system exhibits significantly stronger counter-ion confinement and a distinct electrostatic landscape compared to the 25% system. Finally, hybrid QM/MM calculations integrated with Constrained Density Functional Theory (CDFT) were utilized to evaluate $H_{ab}$ within these specific environments. The computed coupling distributions show a clear correlation with local electrostatic fluctuations induced by differing counter-ion arrangements. These findings indicate that doping-induced environmental disorder is a critical factor modulating intramolecular transport efficiency, providing a theoretical basis for optimizing OMIEC performance through electrostatic engineering. Full article

Understanding interactions between cations and DNA is essential for elucidating the structural dynamics of this fundamental biomolecule. While B-DNA is well known to dominate in long genomic DNA under physiological ionic conditions, its stability in very short DNA fragments—particularly in dilute solutions and in crude oligonucleotide preparations—has remained largely unexplored. Previous spectroscopic studies have primarily focused on long DNA, highly purified oligonucleotides, or high-salt environments, where collective polyion effects dominate. In contrast, the present results demonstrate that even in the absence of chain overlap and under low-salt conditions, Mg²⁺ ions efficiently stabilize the B-form by screening phosphate–phosphate electrostatic repulsion at the intrachain level. The ability to induce an A-to-B transition in crude, ultra-short DNA fragments highlights the fundamental role of divalent counterions in governing DNA conformation and establishes a lower bound for the length scale at which B-DNA can be stabilized. These findings are particularly relevant for dilute biological systems, fragmented DNA samples, and analytical protocols where short DNA fragments and low ionic strength are unavoidable. Full article

2,9-Bis(1,2,4-triazin-3-yl)-1,10-phenanthroline (BTPhen)-based ligands show great promise in the separation of trivalent lanthanides and actinides. Experimental studies have shown that americium forms stronger complexes with the BTPhen ligands than europium; most theoretical studies have so far failed to reproduce these results. In the current study, three different metal forms (the naked cation, its nitrate or perchlorate salts and tetraaqua solvated salts) were used to study different complexation reactions. It was shown that in the case of naked cations and salts, europium forms the most stable complex with the 2,9-bis(1,2-triazin-3-yl)-1,10-phenanthroline ligand in all of the reactions compared. However, europium is also more strongly interacting (compared to americium) with anions and water molecules in the tetraaquatrinitrato or tetraaquatriperchlorato complexes. That shifts the energies of reactions like Am(NO₃)₃·4H₂O + [Eu(H₂O)₄BTPhen]³⁺ = [Am(H₂O)₄BTPhen]³⁺ + Eu(NO₃)₃·4H₂O in favor of the americium being complexed with BTPhen and europium with anions and water. Therefore, the americium complexes with BTPhen become the more stable form, in an agreement with the experimental studies. Comparison of counterion influence (nitrate vs. perchlorate) indicates that bigger preference for americium over europium complexation corresponds to the nitrate complexes and stems mainly from the fact that in M(NO₃)₃(H₂O)₄ europium is stabilized more than in M(ClO₄)₃(H₂O)₄. Full article

High-purity precursors are often required for the targeted synthesis of functional nanomaterials. Molybdenum blue (MB) dispersions are promising precursors for the production of functional materials based on molybdenum oxides and carbides. Here, a facile, spectator-ion-free synthesis of molybdenum blue dispersions via a tailored ion-exchange strategy is reported. By eliminating extrinsic counter-ions, we achieve uniform toroidal nanoclusters (~3.5 nm) of {Mo154} wheel-type molybdenum blue with a precise mixed-valence Mo⁵⁺/Mo⁶⁺ framework and long time aggregative and sedimentation stability. Moderate reduction ratios yield crystalline monoclinic MoO₂, whereas high reduction ratios drive an in situ carbothermal reduction, selectively yielding hexagonal β-Mo₂C/η-MoC phases. This approach establishes a versatile, scalable pathway for engineering molybdenum blue nanoparticles as precursors for oxide- and carbide-based advanced functional materials. Full article

3,4,5-Tris(alkyloxy)benzenesulfonates constitute a class of wedge-shaped dendrons exhibiting liquid crystalline properties, characterized by a diverse and intricate phase behavior that is predominantly governed by the length of the terminal aliphatic chains and the size and nature of the dendrons’ focal group, which collectively influence their self-organization. In systems comprising both two large counterions—wedge-shaped 3,4,5-tris(alkyloxy)benzenesulfonate anions and tetrabutylammonium (N(C₄H₉)₄⁺) cations—a delicate balance between ionic interactions and microphase segregation drives the formation of giant octupoles that self-assemble subsequently into a remarkably ordered lattice. Such phase behavior is consistently observed across a broad range of compounds, with terminal aliphatic chain lengths varying from six to eighteen methylene units. While the structural configuration of the octupoles and the resulting crystalline lattice remains consistent across most compounds, a distinct transition from quantitative to qualitative changes is observed in tetrabutylammonium 3,4,5-tris(hexadecyloxy)benzenesulfonates and 3,4,5-tris(octadecyloxy)benzenesulfonates that exhibit a unique crystalline lattice structure. Full article

Trimeric intracellular cation channel A (TRIC-A) provides counter-ion support for sarcoplasmic reticulum (SR) Ca²⁺ release, yet its physiological role in the intact heart under stress remains poorly defined. Here, we demonstrate that TRIC-A is essential for maintaining balanced SR Ca²⁺ release, mitochondrial integrity, and cardiac resilience during β-adrenergic stimulation. Tric-a^−/− cardiomyocytes exhibited Ca²⁺ transients evoked by electrical stimuli and exaggerated isoproterenol (ISO)-evoked Ca²⁺ release, consistent with SR Ca²⁺ overload. These defects were accompanied by selective upregulation of protein kinase A (PKA)-dependent phosphorylation of ryanodine receptor 2 (RyR2) (S2808) and phospholamban (PLB) (S16). Acute ISO challenge induced mitochondrial swelling, cristae disruption, and Evans Blue Dye uptake, and elevated circulating troponin T in Tric-a^−/− hearts, hallmarks of necrosis-like cell death. Mitochondrial Ca²⁺ uptake inhibition with Ru360 markedly reduced membrane injury, establishing mitochondrial Ca²⁺ overload as the proximal trigger of cardiac cell death. With sustained β-adrenergic stimulation by ISO, Tric-a^−/− hearts developed extensive interstitial and perivascular fibrosis without exaggerated hypertrophy. Cardiac fibroblasts lacked TRIC-A expression and displayed normal Ca²⁺ signaling and activation, indicating that fibrosis arises secondarily from cardiomyocyte injury rather than fibroblast-intrinsic abnormalities. These findings identify TRIC-A as a critical regulator of SR-mitochondrial Ca²⁺ coupling and a key molecular safeguard that protects the heart from catecholamine-induced injury and maladaptive remodeling. Full article

Waterborne polyurethane (WPU) and waterborne poly(urethane-urea) (WPUU) dispersions allow safer and more sustainable manufacturing of rechargeable batteries via water-based processing, while offering tunable adhesion and segmented-domain mechanics. Beyond conventional roles as binders and coatings, WPU/WPUU chemistries also support separator/interlayer and polymer-electrolyte designs for lithium-ion and lithium metal systems, where interfacial integrity, stress accommodation, and ion transport must be balanced. Here, we review WPU/WPUU fundamentals (building blocks, dispersion stabilization, morphology, and film formation) and review prior studies through a battery-centric structure–processing–property lens. We point out key performance-limiting trade-offs—adhesion versus electrolyte uptake and ionic conductivity versus storage modulus—and relate them to practical formulation variables, including soft-/hard-segment selection, ionic center/counterion design, molecular weight/topology control, and crosslinking strategies. Applications are reviewed for (i) electrode binders (graphite/Si; cathodes such as LFP and NMC), (ii) separator coatings and functional interlayers, and (iii) gel/solid polymer electrolytes and hybrid composites, with a focus on practical design guidelines for navigating these trade-offs. Future advancements in WPU/WPUU chemistries will depend on developing stable, low-impedance interlayers, enhancing electrochemical behavior, and establishing application-specific design guidelines to optimize performance in lithium metal batteries (LMB). Full article

This article investigates the thermodynamic driving force of the interaction between lysozyme (Lys) and sulfated β-cyclodextrin (β-CDS), with a particular emphasis on the elusive role of hydration during polyelectrolyte–protein binding. Using isothermal titration calorimetry (ITC), the binding affinity was quantified across varying temperatures and salt concentrations, employing a recently developed thermodynamic framework that explicitly separates the contributions from counterion release and hydration effects. The study reveals that while counterion release is minimal in the Lys/β-CDS system, hydration effects become a dominant factor influencing the binding free energy ΔG_b, especially as experimental temperature deviates from the characteristic temperature T₀. It demonstrates that hydration contributions can substantially weaken binding at increased salt concentration c_s. The high characteristic temperature T₀ and the salt-dependent heat capacity change indicate a complex interplay of water structure and ion association—significantly departing from commonly linear interpretations of ΔG_b vs. log c_s based solely on counterion release effects. This work advances the understanding of polyelectrolyte–protein interactions by providing the first direct quantification of the hydration effect in such complexes and may have an impact on the rational design of biomolecular assemblies and therapeutic carriers. Full article