In the last decade, organoactinide complexes have been active catalysts for the hydroboration of carbonyl moieties, including aldehydes, ketones, amides, isocyanides, and carbonates. The decoration of the metal center by 5, 6, or 7-N-heterocyclic imines increases the electron density at the metal, allowing for remarkable catalytic performances. We report herein the synthesis of a family of thorium and uranium complexes featuring an analogous set of N-heterocyclic iminato ligands built upon a six-membered core ligand framework. The catalytic ability of these complexes was tested in the ester hydroboration reaction, aromatic, aliphatic, and polymeric esters. The reaction was thoroughly investigated, exhibiting an induction period, which was overcome by manipulating the spectator ligands around the metal. Kinetic and thermodynamic studies were conducted to establish the rate law for the reaction and derive the corresponding activation parameters. Deuterium labeling and stoichiometric reactions were performed, and plausible mechanisms were proposed based on the observations.

Selective sodium removal from water sources is crucial for irrigation and other applications, yet challenging due to the abundance of sodium ions compared to essential minerals like calcium and magnesium. Capacitive deionization (CDI) is an emerging electrochemical technique for water treatment and desalination which uses a small electrical potential to adsorb ions in the double layers of microporous electrodes. Given the micropore size is of the same order of magnitude as hydrated ions, CDI offers potential for ion differentiation based on properties such as charge, radius, diffusion constant, and more. Herein, the development of monovalent selective CDI through surface modification of activated carbon cathodes with phosphoric acid groups is described. Cathode phosphorylation induces negative surface charges within the micropores, resulting in enhanced absorption of smaller sodium ions and no calcium uptake during CDI. By applying short, alternating charge–discharge cycles, this membraneless system achieves perfect monovalent cation selectivity with low energy consumption (as low as 0.28 kWh m⁻³), removing sodium from the water without reducing the calcium concentration.

Porous materials with pore sizes spanning the range from molecular to macroscopic dimensions (from angstroms to centimeters) are essential in electrochemical, thermoelectric, nuclear, and solar power sources and in the extraction of oil, gas, and geothermal heat. To enable the clean, fast, and efficient conversion of energy, the porous structure must be designed to allow, modulate, or block the flow of energy transfer vectors. The most important energy streams are mass, charge, heat, radiation, and pressure, and they must be optimized while packing the optimal surface area per device volume. In this Review, we analyze the physical processes that enable energy transfer in porous structures, highlighting recent advances in the design, characterization, modeling, and fundamental understanding of porosity that have enabled breakthroughs across the landscape of energy technologies.

We report generation and stereocontrolled electrophilic trapping of α-boryl carbanions via the selective anionic ring-opening of stereodefined iodomethyl cyclopropylboronic esters. The strategy relies on a lithium–iodine exchange to generate borata alkene intermediates, affording vicinal tri- and tetrasubstituted boronic esters with excellent levels of diastereoselectivity after electrophilic trapping. The stereocontrol arises from conformational preferences of the boron alkylidene, driven by its unique electronic structure. This work expands the synthetic utility of α-boryl carbanions and demonstrates their potential in the stereocontrolled construction of sp³-rich organoboron frameworks.

Anion-exchange membranes (AEMs) enable electrochemical energy devices to operate in alkaline environments, allowing the use of earth-abundant, platinum group metal-free catalysts. This makes them highly attractive for applications such as AEM fuel cells (AEMFCs), water electrolyzers (AEMWEs), and oxygen separators (AEMOSs). However, two key challenges still hinder their commercialization: chemical degradation of the membranes and carbonation from atmospheric CO₂, both of which impair conductivity and reduce long-term performance. Building upon our ex situ novel technique to measure the alkaline stability of quaternary ammonium salts (QAs) and AEMs at different hydroxide hydration levels, in this study we investigate the effect of CO₂ on the stability of the AEMs. Specifically, we evaluate the stability of AEM standard benzyltrimethyl ammonium cations (BTMA⁺) in the presence of mixtures of hydroxide and (bi)carbonate anions at different ratios and hydration levels. Additionally, we introduce a novel technique to simultaneously evaluate (bi)carbonate impact and hydroxide conductivity in AEMs. Our results reveal that the presence of (bi)carbonate anions surrounding BTMA⁺ significantly reduces QA degradation. This phenomenon is further supported by molecular dynamics simulations, which suggest a “salting-out” effect, where water more strongly hydrates hydroxide ions, isolating them from the organic QA sites and reducing degradation probability. These findings provide new insight into AEM behavior in CO₂-containing environments such as ambient air. This study provides new, valuable data to overcome the critical challenge of AEM alkaline stability and opens new avenues for the design of more durable AEM materials, advancing the development of AEMFCs, AEMWEs, and AEMOSs for real-world applications.

Ubiquitination significantly influences human health and disease because it plays an essential role in many cellular signaling pathways. To investigate the effects of different types of ubiquitination, various strategies based on synthesis, semisynthesis, or expression have been developed for protein ubiquitination. Here, we introduce a new method for protein ubiquitination using the SpyTag/SpyCatcher system. By combining protein expression with chemical synthesis, we created enhanced green fluorescent protein (eGFP) with ubiquitin chains consisting of 1–4 units linked through Lys48. This allowed us to study how different ubiquitin chains affect proteasomal degradation by the 26S and 20S proteasomes. While the 26S proteasome only trimmed the ubiquitin chain, the 20S proteasome degraded the different ubiquitin variants, highlighting the flexibility of the 20S proteasome in degrading complex ubiquitinated proteins.

We demonstrate that calculating the spontaneous emission decay rate from metastable resonance states (states with finite lifetimes embedded in the continuum) requires considering transitions to all continuum states, not just to lower states. This holds even when the lifetimes of the metastable states are very long and might be effectively considered as bound states in the continuum. However, employing complex-scaling transformations, this computationally prohibitive task becomes feasible by utilizing methods originally designed for excited bound states for calculation of complex poles of the scattering matrix. As an illustrative example, these methods are applied to calculate the spontaneous emission decay rates of metastable resonance states in a double-barrier potential. The rapid numerical convergence of this approach highlights a new avenue for studying spontaneous emission from metastable states in real-life systems, particularly in many-electron systems, where calculation of the spontaneous emission decay rate from metastable resonances (e.g., autoionization states) is computationally difficult, if not impossible, using the standard (Hermitian) formalism of quantum mechanics.

Substitution of the extended tribenzo-cyclononatriene transforms an achiral cavitand into a chiral host molecule. Calculations of the continuous chirality measure (CCM) predict that tangential substitution induces greater distortion of the unsubstituted bowl-shaped cavitand than radial substitution. We achieved the new cavitands through regioselective synthesis and named them Calochorturils (CTs) after the chiral C₃-symmetric Calochortus venustus tulip. Resolving them into optically pure enantiomers using chiral HPLC enabled their characterization by optical rotation and circular dichroism spectroscopy. Their absolute configuration was determined by X-ray crystallography of an enantiomerically pure triply etherified CT with (S)-BINOL. A comparison of CCM calculations for several solid-state CT derivatives with gas-phase models shows satisfactory agreement. The racemization rate constant for the bowl-to-bowl inversion, k_rac = 7.1 × 10^–6 s^–1, corresponds to an activation free energy barrier of ΔG^# = 115.1 kJ mol^–1. Notably, the CT skeleton is configurationally more stable than the CTV framework, with a 27 h half-life at 334 K in chloroform, compared with 8 h of CTV. Thus, CT derivatives can be handled in solution at room temperature without a significant loss of optical purity.

The phenomenon of field-induced superconductor to insulator transition (SIT) in disordered 2D electron systems has been a subject of controversy since its discovery in the early 1990s. Here we present a phenomenological quantitative theory of this phenomenon which is not based exclusively on the boson-vortex duality used commonly in the field. Within a new low-temperature framework of the time-dependent Ginzburg-Landau (TDGL) functional approach to superconducting fluctuations we propose and develop a scenario in which bosons of Cooper-pair fluctuations (CPFs) condense and localize in real-space mesoscopic puddles under increasing magnetic field due to diminishing stiffness of the fluctuation modes at low temperatures in a broad range of momentum space. Quantum tunneled CPFs relieving the condensed mesoscopic puddles, which consequently pair break into fermionic quasi-particle excitations, dominate the thermally activated inter-puddles transport. The spatially shrinking puddles of CPFs, embedded in expanding normal-state regions, upon further increasing field, suppress the quasi-particle excitation gap and so lead to high-field negative magneto-resistance (MR). Application to amorphous Indium-Oxide thin films shows good quantitative agreement with experimental sheet resistance data. In particular, in agreement with the experiment at low temperatures (i.e. well below the quantum tunneling pair breaking "temperature"), the sheet resistance isotherms are predicted to show a single crossing point at a quantum critical field not far below the MR peak.

Antiaromatic π-conjugated systems provide a powerful framework for understanding ultrafast molecular rearrangements driven by quantum tunnelling over their degenerate double-well potential surfaces. Here, we explore with computational tools the π-bond-shifting automerization in the antiaromatic dinaphtho[2,1-a : 1,2-f]pentalene (1), dinaphtho[1,2-a : 2,1-f]pentalene (2), and a series of substituted derivatives. These molecules exhibit a distinctive feature: local aromatic and antiaromatic rings can interconvert their aromaticity character even close to the absolute zero via unusually fast carbon tunnelling. If these systems can be prepared in a coherent regime, the quantum superposition between the original states would delocalise their nuclear wavefunctions in a state that we describe as a “Schrödinger's aromaticity cat.”