Browse Articles

Cross-linking reaction kinetics of cubic hydrogen silsesquioxane radicals: A theoretical study

In this work, high-level density functional theory calculations were employed to investigate the cross-linking reactions of hydrogen silsesquioxane (HSQ) radicals. We provide a comprehensive elucidation of the whole reaction process, spanning from hydroxylation of hydrogen silsesquioxane radical by water to dehydration condensation of hydroxylated HSQ molecules, by the characterization of key species, energy barriers, and reaction energies. Furthermore, the potential effect of ambient humidity on the cross-linking process was assessed by involving an extra water molecule in both the hydroxylation and dehydration condensation reaction steps. We found that the participation of an extra water molecule can reduce the transition-state energies of both reactions relative to the corresponding reactants by hydrogen-bonds. By incorporating the water concentration at a specific humidity into the kinetic calculations, we demonstrated that the extra water molecules do not catalyze the hydroxylation of HSQ radicals; however, the water molecules facilitate the dehydration condensation reaction, potentially increasing the rate constants by up to a factor of three under high-humidity conditions, as compared to the anhydrous reaction. This study provides a theoretical explanation for that the presence of water promotes HSQ cross-linking, suggesting that a sufficiently high humidity could be beneficial in practical production processes.

Desulfurative Deuteration of (Hetero)Aryl Sulfides With D ₂ O by Nickel Catalysis

ABSTRACT Selective deuteration of (hetero)aryl rings is of great significance and interest, yet it has remained a challenge, especially when employing D 2 O as deuterium source. Herein, the selective desulfurative deuteration of widely available (hetero)aryl sulfides with D 2 O (mostly 1.5 or 3.0 equiv.) has been established by nickel catalysis. This strategy affords an efficient and robust route for the synthesis of a wide range of deuterated (hetero)arenes (87 examples, > 10 different heterocycles) in generally good yields and high deuterium incorporation with good functional group compatibility. The catalytic reaction could be applied to scaled‐up synthesis (e.g., 6.4 g for product 2 , 0.1 mol% Ni catalyst, 590 TON) and late‐stage deuteration of various drugs and bioactive molecules.

<i>Ab initio</i> strong-pump strong-probe doorway-window simulation protocol

We have developed an on-the-fly methodology for the simulation of strong-field pump-probe (PP) spectra using semiclassical trajectory methods. This methodology generalizes the weak-field semiclassical doorway-window (DW) simulation protocol to pump and probe pulses of any intensity. The strong-field DW functions are defined by explicit analytical formulas which are fully determined by the molecular transition dipole moments and electronic energies evaluated along the semiclassical trajectories, so that the weak-field and strong-field PP signals can be simulated at roughly the same computational cost. The developed methodology has been applied for the simulation of strong-field PP spectra of pyrazine. The obtained results vividly demonstrate the advantage of using strong pump and (notably) probe pulses for increasing the information content of PP measurements. In particular, the strong probe pulse significantly enhances the weak transitions originating from the lowest excited electronic states of pyrazine, thereby rendering the nonadiabatic wavepacket dynamics in these weakly allowed states visible.

Jahn–Teller Effect Dominates the Left‐Hand Rule: Magneto‐Optics in Metal Halide Lattice

ABSTRACT Symmetry operation during molecular packing in the crystalline phase determines diverse unique features. Inducing asymmetry in hybrid inorganic–organic metal‐halide typically relies on importing chiral A‐site cations or exploiting hydrogen bonding to distort the lattice. However, achieving precise spatial control over asymmetrical molecules using stereo‐chemical templating strategy remains challenging. Here, we demonstrate that two highly symmetric single crystals, DMA 4 InCl 7 :Sb 3+ and DETABiCl 6 :Sb 3+ , containing isolated SbCl 6 octahedra with idealized octahedral ( O h ) geometry, exhibit a unique case of a static Jahn–Teller effect (JTE) with the interplay of strong spin‐orbit coupling interaction. This inherently handed property drives the spontaneous lowering of symmetry from O h to D 4h , accompanied by structural deformation in the excited states. Under an external magnetic field (B from 0 to 45 T) applied parallel or anti‐parallel to the (100) direction, the A 2u level in the upper position is preferentially populated during relaxation, resulting in a dominant left‐circularly polarized (σ–) emission. Rather than forming an intrinsically asymmetric lattice at equilibrium, chiral preference emerges from a Jahn–Teller‐amplified transient‐state process, yielding a highly effective g m value of up to 8.9×10 −2 . This mechanism will be broadly applicable to d ‐ and p ‐block metal‐activated hybrid metal halides across various dimensionalities.

Quantum scattering of NO A2Σ+ + Ne: Benchmarking the potential energy surface of the collision complex

A new van der Waals potential energy surface (PES) for the NO A2Σ+ + Ne collision complex is reported. This system provides a great test for electronic structure by directly contrasting exact quantum scattering simulations on generated potential energy surfaces with the experiment. The need for a new PES for this system is apparent due to discrepancies in calculated differential cross sections for inelastic rotational scattering on older PESs compared to recent experimental data. We thus perform a detailed benchmarking of the effects of electron correlation, basis set size and type, core correlation, non-Born–Oppenheimer effects, and relativistic effects. Following this, we then construct a new PES and compare time-independent quantum scattering on this new potential to two older ones. Agreement with the experiment is improved on the new PES but still not exact at all scattering energies.

Correction to “Activate 1‐TM Channel of Disordered Rock Salts via Electrostatic Repulsion Regulation for Enhanced Lithium Storage”

Identifiability limits and deep-learning-assisted reconstruction of rotational density matrices for symmetric-top molecules

Recovering the rotational density matrix of a molecular ensemble from time-resolved angular distributions is central to understanding ultrafast rotational dynamics, yet the inverse problem is severely underdetermined. We analyze the forward operator that maps the density matrix of laser-aligned symmetric-top molecules to the angular distribution retrieved in pump–probe experiments and demonstrate through singular value decomposition that 74%–88% of the real density matrix unknowns lie in the null space for maximum angular momentum quantum numbers Jmax = 2–5. This rank deficiency is intrinsic to the measurement geometry and imposes a linear lower bound on reconstruction error: the minimum-norm least-squares (pseudoinverse) solution sets all null-space components to zero, establishing the best achievable error for any linear, unbiased estimator. Nonlinear constraints—positive semidefiniteness, trace conservation, and block symmetries—partially recover null-space information, but the residual error grows with Jmax, reaching 15%–44% for Jmax = 5. We present a two-stage pipeline in which a convolutional neural network trained on simulated data provides a warm start for the fast iterative shrinkage-thresholding algorithm. For both CF3I and CH3Cl across Jmax = 2–6, this approach reduces the Frobenius reconstruction error by 80%–99% relative to optimization from thermal equilibrium, maintaining stable errors of 0.5%–1.1% as Jmax increases. The pipeline is robust to data noise down to a 20 dB signal-to-noise ratio and operates ten times faster than the baseline and outperforms the maximum-entropy approach by a factor of 15–39×. The classical iterative quantum tomography algorithm becomes numerically unstable for Jmax ≥ 4, whereas the proposed method converges reliably at all tested truncation levels.

Selective Oxidation From Toluene to Benzaldehyde via 4 <i>f‐</i> Orbital Involvement

ABSTRACT Selective oxidation has been greatly challenging for the benzylic C─H bond from toluene to benzaldehyde. In this study, Sm 3+ doped Bi 2 WO 6 (Sm‐BWO) nanosheets are constructed through in situ lattice substitution to establish spatially coupled dual‐active sites with interfacial synergy, enabling a high toluene conversion rate of 8550 µm ol·g −1 ·h −1 with high selectivity toward benzaldehyde (&gt;86%). Mechanistic investigations reveal that Sm‐doping induces oxygen vacancies (O V s) and Bi─O frustrated Lewis pairs (FLPs) for benzylic C─H dehydrogenation. The 4 f orbital from localized Sm enables electron injection into π* antibonding orbitals of O 2 . Orbital coupling between 4 f of Sm and 2 p of O creates a directional oxygen species transfer channel across the interface, delivering activated oxygen species for direct oxygenation of benzyl intermediate to benzaldehyde. The f ‐orbital catalysis demonstrates as a generalizable strategy for orchestrating O 2 activation for C─H functionalization. A unique perspective was provided on selective benzylic C─H oxidation by leveraging the f‐ orbital catalysis via inexpensive light rare earth.

Tuning glass-forming dynamics by modifying hydrogen bonding: From polyalcohols to van der Waals liquids

This work investigates how modifications of molecular structure influence the dynamics of hydrogen-bonded glass-formers, with particular focus on glycerol and sorbitol. By systematically eliminating hydrogen bonding through acetylation—yielding glycerol triacetate and sorbitol hexaacetate—and by comparing with previous studies involving pressure, nanoconfinement, and hyperquenching, we assess the role of hydrogen bonds in governing structural and secondary relaxation processes. Broadband dielectric spectroscopy reveals that the removal of hydroxyl groups leads to a substantial reduction in dielectric strength and notable changes in the structural α-relaxation, including variations in glass transition temperature, fragility, and the non-exponentiality parameter. These changes differ qualitatively between glycerol and sorbitol, indicating that the impact of hydrogen bonding depends sensitively on molecular architecture. In contrast, the acetylated systems behave as van der Waals glass-formers and conform to established correlations between dielectric strength and relaxation shape. Analysis of secondary relaxations shows that the Johari–Goldstein β-relaxation persists across all modifications, with its characteristic timescale remaining closely linked to the primitive relaxation time predicted by the coupling model. External perturbations such as high pressure and hyperquenching modify intermolecular coupling and relaxation dispersion without significantly affecting dielectric strength, while nanoconfinement reduces cooperativity and brings the α-relaxation close to the primitive limit. Overall, the results demonstrate that hydrogen bonding strongly influences intermolecular coupling and dynamic heterogeneity, but the fundamental relation between primary and secondary relaxations remains robust.

Crystal‐Field‐Weakening Engineering Unlocks Ultra‐Efficient Eu ²⁺ Near‐Infrared Emission for Emerging Spectroscopic Applications

ABSTRACT Eu 2+ ion has emerged as a promising blue‐light‐excitable near‐infrared (NIR) emitter owing to its parity‐allowed 5d → 4f transition. However, achieving efficient Eu 2+ NIR luminescence remains a great challenge due to the large Stokes shift. Conventional strategies rely on strengthening the crystal field to redshift the emission, but this inevitably enhances electron–phonon coupling, promoting non‑radiative multiphoton relaxation and ultimately compromising efficiency, creating an intrinsic trade‑off between emission wavelength and luminescence efficiency. Herein, we break this trade‑off by proposing a crystal‑field‑weakening engineering strategy that reduces the Stokes shift and suppresses non‐radiative relaxation, thereby significantly enhancing NIR emission in Ca 3 ScHfAlSi 2 O 12 : Eu 2+ . The optimized phosphor exhibits a record internal quantum efficiency of 69.7% at 780 nm under blue excitation, along with high thermal stability (76% retention at 120°C). Mechanistic studies reveal that both intracenter relaxation within Eu 2+ excited states and energy migration between neighboring Eu 2+ ions are substantially suppressed, collectively boosting the NIR radiative efficiency. Finally, a blue‐light‐pumped pc‐NIR‐LED is fabricated, delivering a high NIR output power of 101.52 mW at 350 mA, and demonstrating promising potential in plant lighting, night vision imaging and non‑destructive testing. This work establishes crystal‑field weakening as a promising design paradigm for high‑performance Eu 2+ ‑based NIR phosphors.

Self-assembly: From blueprints to breakthroughs

Well‐Defined RhO ₄ Species Confined in Self‐Pillared Pentasil Zeolite as Efficient Nano Reactors for Hydroformylation of Higher Olefins

ABSTRACT Heterogeneous catalytic hydroformylation of higher olefins often suffers from substrate diffusion limitations and unclear active species. We overcame both challenges using a self‐pillared MFI zeolite anchoring Rh single atoms. By controlling reaction and calcination conditions, we synthesized catalyst Rh 1 @SPP‐MFI (Rh 1 @SPP‐S‐1, Rh 1 @SPP‐ZSM‐5, Rh 1 @SPP‐TS‐1) using a one‐pot method. Extended x‐ray absorption analysis combined with cs‐corrected high‐angle annular dark field scanning transmission electron microscopy (HAADF‐STEM) confirmed each Rh atom coordinated with four O atoms as a well‐defined Rh 1.5+ ‐O 4 structure confined in zeolite cages. The thickness of the zeolite nanosheets was approximately 1.5 b ‐axis unit cells, interlayer spacing ∼ 3.0 nm, making them ideal as nanoreactors. At 353 K and 2.5 MPa, the catalyst achieved a turnover frequency (TOF) of 7074 h −1 for 1‐octene to nonanal, outperforming most homogeneous/heterogeneous catalysts under comparable conditions. Over five cycles (36 h), each Rh atom processed ∼6881 olefin molecules per hour. Density functional theory (DFT) revealed evident electron transfer from O to Rh in the RhO 4 unit, and the flexible Rh‐O bonds mitigated steric hindrance during hydroformylation. This work reveals the microstructure and working mechanism of supported Rh catalysts, and correlates them with the classical homogeneous catalytic mechanism.

Intermolecular dynamics of deep eutectic solvents probed via dynamic optical Kerr effect spectroscopy

Deep eutectic solvents (DESs) are room-temperature liquid-state mixtures composed of two or more components that exhibit a significant depression in their melting points compared with those of their pure components. Owing to their facile preparation and broad range of component combinations, DESs are gaining attraction in materials chemistry and engineering. The intermolecular interactions in DESs are often more diverse than those in ionic liquids or hydrogen-bonding liquids, because they include different kinds of species, which are key to the strong eutectic effect. Thus, DESs are an attractive research target in chemical physics and physical chemistry from both dynamic and static perspectives. This article focuses on the intermolecular dynamics of DESs, particularly those explored using dynamic optical Kerr effect spectroscopy (OKES) and other spectroscopic techniques. OKES is a robust spectroscopic technique for observing molecular dynamics in the low-frequency (or terahertz to subterahertz) region, as it captures both intermolecular vibrations and collective orientational dynamics. Notably, this technique enables detecting dynamics without the need for a probe molecule. This article summarizes key findings from existing research, including characteristic vibrational modes and relaxation processes, as well as their dependence on DES constituents and the effects of water and temperature. Finally, potential directions for future research on DES dynamics are discussed. We hope that this Perspective will help not only to understand the current research situation in DES dynamics, but also to drive further progress and development of the DES and its related research area.

Recyclable Pt‐Catalyzed Biphase Hydrosilylation on Water: From Functionalized Monomers to Polymer Materials

ABSTRACT Ways to resolve the main challenges of the important industrial hydrosilylation process are proposed. Recyclable biphasic Pt/H 2 O‐ and Pt/K B r/H 2 O ‐catalysts are developed. They are prepared by dissolving K 2 PtCl 4 with or without KBr in H 2 O at r.t. for 2 min. Mechanistic studies revealed that previously unknown highly catalytically active single‐atom ( Pt/H 2 O ) or cluster ( Pt/K B r/H 2 O ) [Pt 0 ]‐complexes are generated. H 2 O, Cl – /Br – , and alkenes/alkynes coordinate such [Pt 0 ]‐species, “tuning” their stability, catalytic activity, and structure (single‐atom or cluster). The cooperation of [Pt 0 ]‐species and “on water” effect enabled high efficiency in hydrosilylation. Using Pt/H 2 O and Pt/K B r/H 2 O , a wide range of hydrosilanes, including oligomeric and polymeric ones, as well as aliphatic and aromatic alkenes and alkynes with functional groups, were employed to prepare anti ‐Markovnikov products. Pt/K B r/H 2 O made it possible to obtain cured monoliths and thin films from PDMS derivatives with Si–H‐groups, and vinylsiloxanes, dienes, including gaseous acetylene or butadiene. Pt‐free products, including cross‐linked materials can be isolated from the biphasic catalytic system by decantation. The recyclability (≥15 cycles), low Pt‐loadings and high yields enable a low E‐factor (≤0.07) and a high TON (&gt;10 4 ). Furthermore, a constructed tube‐in‐tube flow reactor allows for effective scale‐up, automatic separation and recycling of the catalytic system with continuous product synthesis.

From fluctuating entropic neck to Rosenfeld–Adam–Gibbs crossover dynamics in supercooled liquids

The pronounced dynamical slowdown in supercooled liquids is accompanied by a sequence of crossovers, most notably from collision-dominated transport at high temperatures to activated structural relaxation at low temperatures, as reflected in the transition from Rosenfeld excess-entropy scaling to Adam–Gibbs behavior. We develop a unified theoretical framework based on a memory-function formalism combined with a configuration-space extension of Zwanzig’s entropic-neck picture. Starting from coupled slow coordinates that describe intra-basin motion and inter-basin escape, we derive a reduced description in which transport occurs through entropically constrained pathways connecting metastable basins in the inherent-structure landscape. In contrast to simplified parallel-channel pictures, the intrabasin coordinate and the neck (transition) coordinate are dynamically coupled, leading to a nonseparable memory kernel with both local (collisional) and collective (barrier-crossing) contributions. At high temperatures, fluctuations sample broad regions of configuration space, the effective neck is wide, and transport is governed by local structural entropy, recovering Rosenfeld scaling. Upon supercooling, progressive constriction of accessible pathways generates an entropic bottleneck whose statistics are controlled by configurational entropy, yielding Adam–Gibbs-type activated dynamics. The formalism provides a semi-microscopic interpretation of the crossover, clarifies its relation to the mode-coupling temperature, and naturally extends to nonequilibrium conditions, where the same entropic-neck mechanism governs the evolution of fictive temperature and its connection to fragility.

Deep Eutectic Solvent Matrix for Hybrid Indium Chloride Glasses With Tunable Luminescence

ABSTRACT Hybrid metal halide (HMH) glasses are emerging as superior photonic candidates, yet their development is fundamentally hindered by the high crystallization propensity of ionic frameworks. To circumvent this thermodynamic barrier, we report a deep eutectic solvent (DES)‐mediated strategy that leverages a dynamically crosslinked hydrogen‐bonding network to kinetically suppress long‐range ordering. Utilizing a DES architecture composed of 3‐aminopiperidine dihydrochloride and 2‐hydroxypropionamide, we successfully fabricate amorphous indium chloride glasses that preserve essential short‐range structural motifs while entirely eliminating lattice crystallinity. This rigid yet adaptive matrix facilitates efficient intersystem crossing through enhanced spin‐orbit coupling and minimizes nonradiative dissipation, thereby enabling robust afterglow emission. Furthermore, the strategic incorporation of [SbCl 6 ] 3− centers and organic fluorophores allows for precise modulation of excited‐state dynamics via host‐guest energy transfer and triplet excitons harvesting, yielding broad‐spectrum luminescence from blue to red. These hybrid glasses integrate prompt fluorescence, self‐trapped exciton emission, and room‐temperature phosphorescence, achieving a maximum lifetime of 283.41 ms and a photoluminescence quantum yield of 46.90%. This multifunctional platform demonstrates significant potential for multilevel anti‐counterfeiting and spatiotemporal information encoding. Ultimately, this work establishes DES chemistry as a versatile paradigm for customizing HMH glasses, paving the way for programmable, high‐performance photofunctional materials.

Using a low-storage contour-integral eigensolver for nonsymmetric matrices with collocation to compute vibrational spectra

Collocation is advantageous for computing vibrational spectra because it obviates the need for quadrature. However, to use collocation, one must solve a non-Hermitian matrix eigenvalue problem. Simple, accurate Lanczos algorithms that require storing only a few vectors can be used only for symmetric matrices. Established eigensolvers for nonsymmetric problems require storing (and orthogonalizing) many vectors. For large matrices, they require a lot of memory. We propose a low-storage eigensolver combining the block Sakurai–Sugiura method and the multi-shift quasi-minimal residual linear solver. It requires storing only a few vectors. The method has many of the advantages of the well-known Cullum–Willoughby Lanczos approach for symmetric matrices.

Speciation‐Controlled C–F Bond Functionalization Enabled by Zwitterionic Pnictinidenes

ABSTRACT Low‐valent pnictogen systems have recently emerged as redox catalysts for C–F activation. However, catalytic turnover has remained largely restricted to hydrodefluorination pathways reliant on metallomimetic reductive elimination. Herein, we report a defluorinative functionalization platform mediated by zwitterionic pnictinidenes that enables the formation of diverse C–X bonds (X = C, O, S, N, P, Se) from polyfluoro(hetero)arenes under mild conditions. Combined experimental and DFT studies reveal that, although a Sb(I)/Sb(III) redox cycle could be accessed, catalysis instead proceeds through Sb(III)–F species that promote C–F substitution via a redox‐neutral manifold. These findings establish catalyst speciation as a decisive mechanistic branch point, showing how strategies to modulate ligand scrambling events may enable alternative pnictogen‐based redox or redox‐neutral manifolds.

GTAttn-XC: Physically constrained attention for nonlocal density functionals

Machine-learning-based nonlocal density functional approximations have demonstrated substantial potential in advancing the applicability of electronic density functional theory. However, most existing approaches rely on handcrafted local or nonlocal descriptors, which limits their scalability in modeling long-range electronic responses. In this work, we propose a novel exchange–correlation functional approximation model—GTAttn-XC, which introduces a learnable attention mechanism to enable unsupervised modeling of long-range electronic responses. By coupling a multiscale real-space grid graph representation with attention operators, the proposed method achieves a unified description of local accuracy and nonlocal interactions, while avoiding the computational overhead associated with explicit high-order correlation terms. Evaluations on multiple benchmark datasets, including MGCDB84, demonstrate that the model consistently delivers high accuracy across a range of tasks, such as weak interactions, reaction energies, barrier heights, and thermochemical energies. These results establish a new technical pathway toward high-accuracy nonlocal exchange–correlation approximations.

Homonuclear Dual‐Atom Cobalt Sites for Enhanced Selective Hydrogenation

ABSTRACT Single‐atom catalysts based on non‐noble metals have demonstrated remarkable selectivity in selective hydrogenation. However, their electron‐deficient metal sites and the absence of adjacent metal sites often limit their hydrogenation activity. In this study, a homonuclear dual‐atom cobalt site catalyst (Co‐DAC) containing Co─Co bonds was synthesized by adsorbing a Co 2 ‐complex onto ZIF‐8 through a simple impregnation–pyrolysis process. The intrinsic activity of Co‐DAC in selective hydrogenation, including nitroarene hydrogenation to arylamines and alkyne semi‐hydrogenation to alkenes, was then investigated. The turnover frequency of Co‐DAC was 431 h − 1 in nitrobenzene hydrogenation and 1665 h − 1 in phenylacetylene semi‐hydrogenation. These values were 6.8‐fold and 17.5‐fold higher than those of the single‐atom catalyst, respectively. Moreover, it demonstrated broad substrate scope in these two reactions. Mechanistic studies revealed that the Co─Co dual‐atomic sites enhanced the adsorption capacity for nitro groups. Simultaneously, due to the electron coupling between Co─Co atom pairs, the electron density on the Co atoms increased. This facilitated the activation of H 2 and the desorption of aniline from the Co sites. Furthermore, the Co─Co sites enabled the homolytic cleavage of H 2 with a lower activation energy barrier. Therefore, Co‐DAC exhibited significantly improved catalytic performance in selective hydrogenation.