The unique chemical reactivity offered by photochemistry has driven a growing interest in the design of new photocatalysts with diverse chemical properties. Incorporating heavy atoms into the core of chromophores presents an excellent opportunity to achieve this by enabling a long-lived excited state. Herein we report the design, synthesis, and characterization of new Sb- and Bi-based dipyrrins with a significantly increased stability in solution, improved luminescent properties, as well as their use in photocatalysis. Furthermore, the applicability of a new Sb-dipyrrin photosensitizer Ar^OMe-Sb-Br is highlighted in the oxidation of different functional groups, performing especially well in the oxidation of alkenes (TON up to 5500). In addition, the singlet oxygen efficiency was found to be Φ_Δ= 0.76, a value as high as benchmark photosensitizers such as chlorophyll a and metalloporphyrins. We have performed further investigations using cyclic voltammetry under light irradiation with complementary density functional theory (DFT) calculations to elucidate the redox properties of our new set of heavy pnictogen dipyrrins. Despite the theoretical and experimental challenges, both cyclic voltammetry and DFT corroborate the formation of a cationic complex resulting from light-induced bromide dissociation. Our work paves the way for exciting new possibilities in light-driven applications using main-group elements.

Circularly-polarized light is well-known to induce, or flip the direction of, magnetization in solids. At its heart, this arises from time-reversal symmetry breaking by the vector potential, causing inverse-Faraday or analogous physical effects. We show here that very short few-cycle pulses can cause similar phenomena even when they are linearly-polarized and off-resonant. We analyze the new effect with ab-initio calculations and demonstrate that it similarly arises due to broken time-reversal symmetry and is carrier-envelope-phase (CEP) sensitive. Coherently tuning the CEP causes the induced magnetism to oscillate from zero to few percent Bohr magneton within few femtoseconds. By changing the laser angle and intensity, the magnetization sign and magnitude can be controlled. Remarkably, due to the nature of the physical mechanism that relies on spin-orbit interactions and orbital currents, the magnetization survives CEP-averaging and the effect should be accessible even in the absence of CEP stabilization. Our work opens new routes for ultrafast coherent tuning and probing of magnetism and circumvents the need for circularly-polarized driving or external magnetic fields.

NiPS3 is an exfoliable van-der-Waals intralayer antiferromagnet with zigzag-type spin arrangement. It is distinct from other TMPS3 (TM: transition metal) materials by optical excitations into a strongly correlated state that is tied to the magnetic properties. However, the related, fundamental band structure across the antiferromagnetic phase transition has not been probed yet. Here, we use angular-resolved photoelectron spectroscopy with {\mu}m resolution in combination with DFT+U calculations for that purpose. We identify a characteristic band shift across TN. It is attributed to bands of mixed Ni and S character related to the superexchange interaction of Ni 3t2g orbitals. Moreover, we find a structure above the valence band maximum with little angular dispersion that could not be reproduced by the calculations. The discrepancy suggests the influence of many-body interactions beyond the DFT+U approximations in striking contrast to the results on MnPS3 and FePS3, where these calculations were sufficient for an adequate description.

Inverse-freezing fluids, IFFs, are unique materials, which undergo a reversible, endothermic liquid-to-solid phase transition upon heating. Recent findings reveal that this transition can also be triggered by mechanical impact, wherein the impact’s shockwaves enter the IFF and induce the liquid-to-solid phase change. This results in the attenuation of these shockwaves within the material. Although the precise mechanism of the attenuation remains to be fully elucidated, it is likely that a portion of the mechanical energy is absorbed via the endothermic phase transition. This energy-uptake route positions IFFs as promising candidates for integration into shockwave-mitigating systems, particularly as anti-trauma components in lightweight ballistic armor. In this study, anti-trauma units based on 20%Wt. aqueous methylcellulose, AMC, IFFs were prepared and, for the first time, tested in an accredited firing range. Their ability to attenuate blunt trauma from 7.62×51 mm FMJ NATO rounds was evaluated against U.S. National Institute of Justice, NIJ, performance standards. While anti-trauma units based on the 20%Wt. Although AMC alone was borderline in its ability to meet the NIJ criteria, compositing it with ballistic fibers and thin aluminum sheets significantly enhanced the performance. The resulting composite systems exceeded NIJ trauma limits, demonstrating the feasibility of combining IFF-based anti-trauma units into practical, field-relevant armor configurations.

Single-atom catalysts (SACs) possessing well-defined active sites of singular metal atoms have gained prominence in the field of electrocatalysis as they can be tuned to enhance activity and stability. In this study, a critical-raw-material (CRM)-free SAC is synthesized for the oxygen reduction reaction (ORR) in alkaline media by pyrolyzing polyimide nanoparticles and Fe without using a sacrificial template. Upon purification, the resulting catalyst demonstrates outstanding performance as cathodes in anion-exchange membrane fuel cells (AEMFCs) owing to sufficiently stabilized Fe single-atoms at the FeN₄ sites yielding a peak power density (P_max) as high as ∼1.8 W cm⁻² and specific power values up to 11.3 W ${\mathrm{mg}}_{\mathrm{PGM}}^{-1}$ ; the latter being the greatest reported among CRM-free cathode AEMFCs. The SAC also shows remarkable in situ durability under a very high current density of 1000 mA cm⁻², a first introduced here, with only a 2 mV h⁻¹ decay. Most impressively, when the SAC is combined with a NiMo anode to test a completely CRM-free high-temperature (HT)-AEMFC at 118 °C, a P_max of 372 mW cm⁻² and limiting current density of ∼1.14 A cm⁻² are achieved. This work represents a significant milestone in the development of durable SAC cathode catalysts for the next generation of CRM-free AEMFCs.

The last two decades of research on carbon dioxide have demonstrated that CO₂ is far more than a waste product of aerobic metabolism leading to acidosis, and that it elicits biological responses directly via non-pH-dependent molecular interactions. New specialized methodologies have mapped CO₂ incorporation into specific regions of CO₂-sensitive proteins and linked these events to altered cellular function. CO₂ affects a host of biological responses related to respiratory disease, including control of respiration, protein maturation, alveolar fluid homeostasis, wound repair, innate immunity, host defense, and airway contractility. Elevated CO₂ (hypercapnia) appears to be primarily deleterious in pulmonary diseases, leading to a heightened interest in strategies to reduce excess CO₂ in patients with hypercapnic respiratory failure. Here, we summarize recently generated knowledge on molecular CO₂ sensing and signaling, and the potential translational relevance of these processes in the context of respiratory disease. We need to grow this field further by encouraging experts in basic and translational science to contribute to more fully elucidating CO₂ sensing, signaling and downstream effects. Understanding the biology and clinical consequences of perturbations in CO₂ homeostasis should no longer be considered secondary to studying oxygen sensing and signaling in respiratory medicine.

The robust titanium-based metal–organic framework MIL-125(Ti)-NH₂  was loaded with Cu²⁺ ions (2%, 5%) as well as by nanoparticles of Cu⁰ (5%). The ionic copper species were found to be atomically dispersed within the MOF pores, inducing a slight lattice expansion. In contrast, metallic copper was predominantly deposited at the MOF external surface, resulting in a more significant decrease in BET area. Optical spectroscopy and computational studies revealed that Cu⁰ modification led to a notable narrowing of the bandgap, attributed to the emergence of additional electronic states above the valence band edge, an effect not observed upon incorporation of Cu²⁺ ions. Photoluminescence spectroscopy showed reduced emission intensity upon copper incorporation, with the most pronounced quenching seen in Cu⁰-modified samples. This reduction is associated with both enhanced charge separation and non-radiative deactivation pathways, including phonon-assisted processes, as supported by time-dependent DFT calculations. Nanosecond transient infrared spectroscopy (TRIR) further demonstrated a ligand-to-metal charge transfer from the NH₂-BDC linker to the Ti–O cluster in pristine MIL-125(Ti)-NH₂  , which was extended through localized Ti–O–Cu interactions upon Cu incorporation. The TRIR measurements further indicated an electronic miniband located some 0.2-0.3 eV above Ec for all types of samples. Under visible light, the Cu⁰-loaded MOF outperformed the Cu²⁺-modified analogue in photocatalytic hydrogen evolution. The superior performance of metallic Cu⁰ over ionic Cu²⁺  may originated from reduced rate of radiative recombination as well as from its higher surface energy, which promotes the adsorption of water molecules.

The gas-phase hydrogen exchange reaction (HER) is the most fundamental chemical process for benchmarking quantum reaction dynamics. In this Letter, we focus on controlling HER by means of strong light-matter coupling inside a resonant cavity, an approach often called polariton chemistry. In particular, we focus on the isotopic variation of HER involving collisions between molecular hydrogen H$_2$ and deuterium atom D, i.e., H$_2$+D$\to$HD+H. We find that the asymmetry introduced by the different isotopes, despite being small, enables strong cavity-induced modifications of reaction rates. Outside of the cavity the reaction is as usual D+H${_2}$$\to$DH+H. However, inside the cavity another type of reactions take place where D+H$_2$$\to$DH+H+E$_{photon}$, where E$_{photon}$=$\hbar\omega_{cav}$. Our results show that HER is an ideal platform to make a significant step toward closing the gap between theory and experiment in polariton chemistry.

This paper presents a novel continuous-flow electron spin resonance (ESR) microfluidic device designed for both continuous-wave (CW) and pulsed ESR measurements on sub-nanoliter liquid samples. The system integrates a planar surface microresonator (ParPar type) operating at ∼9.4 GHz with a precision-fabricated quartz microfluidic chip, enabling spatial confinement of the sample within the resonator’s microwave magnetic field hotspot while minimizing dielectric losses. The effective sample volume is ∼0.06 nL, and the device supports standard microfluidic connectors, facilitating both continuous and stopped-flow experiments. Using a 1 mM aqueous solution of deuterated Finland trityl (dFT) radical, CW ESR measurements yielded a peak signal-to-noise ratio (SNR) of ∼83 for a 100-point spectrum acquired over 80 s, with a resonator quality factor of Q ∼15–20. This corresponds to a spin sensitivity of ∼1.04 × 10⁹ spins/√Hz/G. Pulsed ESR measurements, performed with 0.1 W microwave power and 10 ns π pulses, achieved an SNR of ∼47 with 1 s of averaging, corresponding to a spin sensitivity of ∼7.8 × 10⁸ spins/√Hz. A Rabi frequency of ∼50 MHz was measured, indicating a microwave conversion efficiency of ∼56 G/√W. Both the pulsed spin sensitivity and Rabi frequency are consistent with simulated values. This device represents a significant step toward ESR-based detection of individual, slowly flowing cells—analogous to flow cytometry but with magnetic resonance contrast. With future enhancements such as higher operating frequencies, cryogenic integration, or optimized resonator geometries, the system is expected to enable practical ESR measurements at the single-cell level.

Benzene, toluene, ethylbenzene, and xylene (BTEX) are widespread volatile organic compounds commonly present in fuels and various industrial materials. Their release into the atmosphere significantly contributes to air pollution, prompting strict regulatory concentration limits in ambient air. In this work, we introduce Multiphoton Electron Extraction Spectroscopy (MEES) as an innovative technique for the sensitive, selective, and online detection and quantitation of BTEX compounds under ambient conditions. MEES employs tunable UV laser pulses to induce the resonant ionization of target molecules under a high electrical field, with subsequent measurement of the generated photocurrent. We now demonstrate the method’s ability to detect BTEX in ambient air, at part-per-trillion (ppt) concentration range, providing distinct spectral signatures for each compound, including individual xylene isomers. The technique represents a significant advancement in BTEX monitoring, with potential applications in environmental sensing and industrial air quality control.