To better understand the properties of carbene and biscarbene species derived from bisdiazo compounds with varied terminal groups, a density functional theory (DFT) study was conducted on bisdiazo compounds with four terminal groups (bisdiazo-X, where X=H, Me, NO and NH) and their mono- and dicarbene derivatives. The studies included computation of their frontier molecular orbitals (FMOs), electronic structures, electrostatic potential (ESP) and polarity, as well as their IR and UV-vis spectra and their color in THF solutions. For bisdiazo compounds at both ground and excited states, the computational results matched well with published experimental data. The formation of carbene species from bisdiazo compounds was confirmed via a generalized IRC path calculation and IGMH analysis. The reaction sites and the lone pair electron locations were predicted using minimum ESP (i.e., ESPmin) and orbital-weighted Fukui dual descriptor for the possible intermediates in the transition state, along with spin density analysis through EPR/ESR predictions. Additionally, physisorption of bisdiazo and carbene species onto single-layer graphene was evaluated through geometry optimization, in which π-π stacking among the aromatic-ring likely determines surface packing via the simulated scanning tunnelling microscope (STM) images. The carbene species permit controlled growth of the patterned functional organic surfaces.

A rigid H-shaped [2]rotaxane shuttle composed by a mechanically interlocked 24-crown-8(24C8) macrocycle on a thread containing two symmetrical benzimidazole (Bzi) stations bound with a central 2,2'-bipyridyl (Bipy) core is addressed in CHCl solution with all-atoms molecular dynamics simulations. The experimentally observed conformational preferences of the 24C8 ring quantitatively characterizing the free-energy landscape driving its reversible translocation over the synthetic Stop-[Bzi-Bipy-Bzi]-Stop thread at room temperature have been reproduced. Also, this analysis to a translationally inactive form in N,N-dimethylformamide (DMF) dilute solution following the coordination of PtCl to the Bipy chelate site is extended. In this respect, in the presence of PtCl, the optimized geometry within the density functional theory (DFT) framework is fully characterized in terms of quantum theory of atoms in molecules (QTAIM) descriptors. Converged DFT wavefunctions in a continuum environment are analytically investigated by means of electron density ρ(r), local electronic energy density, H(r), electron localization function (ELF), and delocalization index δ(X,Y) analysis. The derived picture highlights that the contextual presence of supramolecular contacts confining the 24C8 ring over its primary recognition site, and of a planar square (Bipy)-N-PtCl coordination environment parallel to the axle should actually be effective in suppressing the shutting movement as hypothesized via H-nuclear magnetic resonance measurements.

Electron-beam (e-beam) technology plays a crucial role in high-dose (MGy) irradiation applications, which heavily rely on high irradiation efficiency and uniform dose distribution. However, the immediate visualization of precise e-beam dose and spatial dose distribution is challenging due to high-throughput flux and strong electron scattering. Herein, a wide dose-response range (0-3.75 MGy) and high spatial resolution (<100 μm) e-beam dosimetry based on photonic crystal (PC) polymer films is developed. The diffraction peak of the PC film demonstrates a continuous blue shift within the visible light wavelength range as the dose increases. This phenomenon is attributed to the gradual collapse of the inverse opal structure under irradiation. The naked-eye readable dosimeter shows excellent pre-and post-irradiation stability, demonstrating remarkable resistance to environmental factors such as temperature fluctuations and ultraviolet exposure. Notably, the dosimeter can detect e-beam scattering clearly when using a metal mask for radiation shielding. This work provided valuable insights into the radiation degradation behavior of PC structures under high-dose e-beam irradiation, while simultaneously offering a novel perspective for MGy-level e-beam dose and spatial distribution detection.

The development of effective and sustainable catalysts for the long-term use of CO is highly dependent on understanding how CO is adsorbed and activated on catalysts, mainly based on transition metals. Since catalysis is inherently a localized phenomenon and CO tends to adsorb at the metal centers due to differences in electronegativity, detailed information on the mechanisms of CO capture can be obtained by studying simplified molecular models, such as transition-metal dimers. Using such dimer models, this article addresses the importance of d-orbitals that facilitate the adsorption and activation of a CO molecule. In addition, the influence of back-bonding is observed, where electrons from the filled 2π orbitals of CO are donated to the vacant orbitals of metal atoms, in different adsorption configurations of CO molecule. The findings elucidate a clear connection between back-bonding and CO adsorption mechanism, highlighting particular configurations that facilitate optimal activation. Through evaluation of the correlation among d-orbitals, back-bonding, and CO activation within transition-metal dimers, a viable approach is presented to design efficient catalysts to capture carbon dioxide.

The outstanding alkaline hydrogen evolution reaction (HER) performance of MoP-NiCoP heterostructure has been reported. However, the mechanism behind its catalytic activity remains unclear, and the underlying synergistic catalysis has not been revealed at the atomic scale. Based on these research gaps, the theoretical investigation on the MoP-NiCoP heterostructure is conducted, revealing that the MoP-NiCoP heterostructure exhibits superior HER activity (  = -0.016 eV) but limited oxygen evolution reaction (OER) performance (  = 2.589 eV). Electronic structure analysis demonstrates that interfacial charge redistribution optimizes the adsorption strength of the H* intermediate, significantly lowering the HER energy barrier while restricting the O* → OOH* transition, thus hindering OER processes. Doping strategies (e.g., W, Ta) further enhance HER performance and a linear scaling relationship between the d-band center ( ) and HER activity descriptor ( ) shows strong correlation (R = 0.993). This work reveals the origin of the high intrinsic HER activity and the interfacial synergistic mechanism in the MoP-NiCoP catalyst, verifying its lack of effective OER activity. It further identifies a novel strategy for directional enhancement of catalytic performance through electronic structure modulation, establishing a theoretical framework for designing bifunctional electrocatalysts on experiments.

Germanium (Ge) is a crucial semiconductor material. Germanium powder is typically manufactured through hydrogen reduction of germanium dioxide (GeO). However, the traditional reduction method frequently results in suboptimal hydrogen utilization, larger-than-desired granular sizes, and nonuniform granular distribution. In this article, a novel vertical gas-flow field reduction process is proposed for addressing the above challenges, and the effects of reduction temperature and hydrogen flow rate are investigated. The results show that the novel process promotes the contact between GeO and hydrogen, reducing HO partial pressure at the reduction interface. Accordingly, conversion efficiency (the ratio of weight loss ratio W to the theoretical maximum weight loss ratio W) is much higher than the traditional method by 20%-30%, and the obtained Ge powder conforms to the desired dimensions and uniformity. This article provides a novel process for manufacturing high-quality germanium powder with a short production cycle, less hydrogen consumption, and low energy consumption.

Lignin valorization is restricted by the stability of its methoxy groups, creating a critical need for efficient demethylation strategies. Here, density functional theory (DFT) is employed to dissect the mechanistic pathways of demethylation in lignin model compounds, guaiacol and syringol, using protic ionic liquids (PILs) that act as both solvent and catalyst. Conductor-like Screening Model for Real Solvents (COSMO-RS) analysis identifies monoethanolammonium acetate ([MEOA][Ace]) as the most promising medium, attributed to its strong hydrogen bonding network and solvation ability. By integrating implicit and explicit solvation models, it is revealed that an acid-catalyzed hydrolytic mechanism governs demethylation, with PILs stabilizing crucial transition states and intermediates. Complementary electronic structure evaluations, including highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gap analysis, charge distribution, and electrostatic potential mapping, demonstrate how PILs lower energetic barriers and enhance reactivity. To simulate realistic environments, this study is extended to lignin dimer complexes with varying water content, uncovering how water-bridged solvation reverses demethylation preference from guaiacyl to syringyl units. This mechanistic shift aligns with experimental observations showing faster S-unit reactivity in hydrated systems. Together, these findings provide atomic-level insight into lignin demethylation dynamics and highlight how tuning acid concentration in PILs can accelerate kinetics, enabling a rational pathway toward next-generation biomass conversion technologies.

The photochemical growth of silver nanotriangles immobilized on a solid substrate, under the photoirradiation at a suitable wavelength by a depolarized light source, has been reported in this work using both glass and indium-titanium oxide-coated glass substrates. A 2D growth of the surface-immobilized silver nanotriangles is observed, which leads mostly to the formation of larger nanotriangles along with a small population of other plate-like nanostructures. This observation is rationalized by invoking the role of surface plasmon resonances at optical frequencies, especially the in-plane dipolar and higher order plasmon modes that are rather efficiently excited due to fixed orientation of surface-bound nanotriangles. By this technique, a large-scale 2D array of nanoplates with a tunable surface coverage, suitable for development of modulable templates for surface-active applications, is created. A tunable surface enhanced Raman scattering (SERS) response, as a prototype for plasmonic application, has also been demonstrated in the present study, obtaining a high SERS enhancement factor of ≈10 with the signal intensity correlated with the number-density of the surface-grown nanoparticles. Apart from tunable SERS sensitivity, the current protocol of surface-immobilized nanotriangle synthesis will also be useful for creating plasmonic nanoarchitecture for optical applications and portable sensor for biomolecules.

Halide perovskite (HP) versatility for optoelectronic and electrochemical applications is mainly due to their ability to engineer cation mixtures at the A-site within the ABX stoichiometry. Acetamidinium (AC) is a common cation used in these mixed compositions, but its effects on the material's properties have not been addressed in detail. In this work, prototypical methylammonium lead iodide (MAPbI) compositions partially substituted with AC are synthesized and analyzed for structural, electrical, optoelectronic, and stability properties. Results reveal a solubility limit of around 10% AC, lower than encountered in the literature, with slight effects on the phase transition temperatures. As expected, substitution with AC significantly reduces electronic conductivity and I-V hysteresis but only marginally increases the bandgap energy. Contrary to literature results, light-accelerated degradation tests show that AC incorporation does not significantly enhance the materials' stability. Among several reasons, this might be related to weak interactions between AC cations and the inorganic framework. This study establishes the effects of AC substitution in halide perovskites and provides insights into optimizing A-site compositions for optoelectronic and electrochemical applications.

Both the carbonyl and hydroxyl O atoms of the carboxyl group are capable of acting as electron donor in the context of noncovalent bonds. These two O atoms of acetic acid are each allowed to form an H-bond with HCl and a halogen bond with IF, and the interactions are monitored by quantum chemical calculations. The electrostatic potential on the carbonyl O is more negative than that on OH, and the HOMO is weighted toward the carbonyl. The interaction energies are consequently considerably stronger for the CO. A series of ligands are added to the carboxyl group that extract electron density from the carbonyl O and add density to OH. These arrangements enhance the interaction energies involving OH, some by nearly 50%. These same ligands have a lesser effect on bonds involving CO, many of which are actually strengthened, despite the reduced magnitude of its negative potential. Consequently, the CO remains the favored site for an electrophile, regardless of the ligands that might be present.

Upregulation of serine arginine protein kinase 1 (SRPK1), a protein responsible for phosphorylation of Ser-Arg rich residues aimed at SR proteins, is associated with apoptosis, poor survival, etc. Catalytic sites of the kinase proteins are incompetently preserved, causing difficulty in developing competitive inhibitors for ATP binding sites with broad selectivity; hence, search for inhibitor for the ATP binding pocket of SRPK1 is a necessity for medication against carcinogenesis. Natural product database is explored, and six small molecules are identified; having tolerable pharmacokinetics (low blood brain barrier, moderate clearance rate etc.) and quantum chemical properties are checked. Molecular docking study followed by molecular dynamics give insights into the effective interactions at the ATP pocket. Ligands are screened by MM-GBSA/NMA protocol, followed by estimation of unbinding potential of mean force (PMF) using well-tempered metadynamics. Well-tempered metadynamics confirmed unbinding PMF of -23.71 kcal mol for CNP0199214 and -14.81 kcal mol for MSC1186 (Lig_ref) to a relative difference in PMF of the screened ligand to be ≈7 kcal mol. A probable gating mechanism is observed for the reference ligand (Lig_ref) at the protein interface resulting multiple minima in PMF, whereas Lig_4 (CNP0199214) exhibits greater affinity toward the active pocket and therefore choice for a potent compound.

Stronger molecule-electrode coupling is associated with higher conductance in single-molecule junctions. This has been taken to imply that more coordination-what will be referred to here as higher denticity-between the molecule and the electrode is expected to impart higher conductance to the overall junction. Herein, this assumption using a single molecule construct, a rigid N-heterohexacene molecule with tetradentate ethyl sulfide (-SEt) anchors, is examined. Thus, rather than comparing a series of molecules with different anchoring groups, it is investigated how variations in effective denticity arise naturally within one molecule. Using the nonequilibrium Green's function technique in conjunction with density functional theory and mechanically controlled break-junction (MCBJ) experiments, it is found that increasing the denticity between the molecule and the electrode does not yield the expected higher conductance. Instead, simulated break-junction traces reveal a strong correlation between conductance and the dihedral angle between the electrode and the molecular core, with changes to dihedral angles providing far more variation in conductance values than denticity alone. In fact, it is shown that counter to naïve expectations, different denticities cannot be distinguished by conductance, merging instead into a single conductance feature. This is supported by MCBJ experiments on this molecule, where only a single conductance state is identified, suggesting that the expected denticity-dependent multistate conductance behavior is dominated by the effect of dihedral angles. By restricting dihedral angles to more favorable values by molecular design, the calculations show that significantly higher conductance values can still be achieved despite the limitations imposed by dihedral-denticity coupling. The work demonstrates that mere denticity may not be sufficient to design highly conductive molecular junctions, and that the association of conductance features with different denticities should be treated with caution.

Understanding the mechanism of CO cycloaddition with epoxides under mild conditions is vital for advancing green carbon capture and utilization strategies. This work investigates the catalytic role of a defective ZIF-8 model with Zn-OH-Zn moieties and bromide (Br) assistance in promoting the conversion of CO and propylene oxide into propylene carbonate. Density-functional theory calculations reveal that, in the absence of a catalyst, the reaction proceeds through high activation barriers (52.02 kcal mol and 59.31 kcal mol for the α and β pathways, respectively). Upon introducing the Zn-OH-Zn site and Br, the energy barrier for the rate-limiting ring-opening step is drastically lowered to 14.45 kcal mol, confirming the synergistic effect between Lewis acid/base sites and halide assistance. The calculated reaction energy of -13.89 kcal mol aligns well with the experimental enthalpy change (-12.64 kcal mol). This study provides molecular-level insights into the cooperative catalytic mechanism and supports defect-engineering strategies for metal-organic frameworks in CO fixation applications.

Electrocatalytic nitrogen reduction reaction (NRR) provides a promising strategy for effective nitrogen fixation under mild conditions. Herein, structural stability and NRR catalytic activity of 29 transition metal (TM, Sc-Hg) atoms adsorbed Janus 2H-WSSe monolayers are studied using the first-principles calculations. Six screened TM@S/Se-WSSe (TM = Os, Re) and TM@Se-WSSe (TM = Ir, Mo) systems are considered promising single-atom catalysts (SACs) due to low limiting potential (-0.36 to -0.73 V) and high Faradaic efficiency (FE > 90.61%). High catalytic activity arises from the donation and back-donation mechanisms between the empty/unoccupied TM-d orbitals and the bonding/antibonding N-p orbitals, which significantly promote the activation of N and the charge transfer in the subsequent hydrogenation reactions. In addition, the catalytic activity trend of the screened TM@WSSe systems is further analyzed by four descriptors (ΔG, ΔG, ΔG, and φ). The high activity can be achieved by individually tuning ΔG or ΔG. Meanwhile, the TM@WSSe with ΔG = -1.38 eV and φ = 6 exhibits the best catalytic activity. The results provide insights into designing efficient nitrogen fixation electrocatalysts.

Boron clusters doped with lanthanides reveal diverse topological structures and low oxidation states, expanding the types of boron-based nanomaterials and offering opportunities for the continuous expansion of the boundaries of the valence states of rare earth metals and boron chemistry. In this work, the crystal structure analysis by particle swarm optimization method combined with density-functional theory is applied for SmB clusters in the range n = 3-10 and elucidates the evolutionary patterns of geometrical structure. An analysis of chemical bonding patterns and natural atomic populations indicates that the Sm 4f electrons do not participate in bonding. In all the SmB clusters considered, the oxidation state of Sm atoms is +2, whereas the typical oxidation number of the lanthanide atoms is +3. The corresponding electronic configuration of the Sm atom in this oxidation state is 4f for SmB, and the 6s orbital are practically empty. The 2D planar SmB, and 3D umbrella-shaped SmB exhibit both σ and π aromaticity. The Sm atom forms localized σ bonds with the host cluster in SmB and SmB, while in SmB, it forms delocalized π bonds with the host cluster, demonstrating the significant influence of the structural dimension on their interaction behavior.

Reliable approximations to coupled-cluster (CC) methods are highly desirable for accurate yet efficient computations of barrier heights, reaction energies, and other molecular properties. Among these methods, domain-based local pair natural orbital CC with singles, doubles, and perturbative triple excitations [DLPNO-CCSD(T)] is widely used due to its formal linear scaling with the system size. However, since DLPNO-CCSD(T) remains costly, the extension to multilevel (ML) variants becomes an obvious route. This strategy can be made even more economic with the pair-selected ML ansatz [M. Bensberg and J. Neugebauer, J. Chem. Phys. 157, 064102 (2022)] to DLPNO-CCSD(T) with a semi-canonical (SC) perturbative triples correction. This ansatz uses an automatic partitioning of orbital pairs according to their contribution to the overall correlation energy change in a chemical reaction. Herein, the advantages of this approach are demonstrated for closed-shell organic reactions of the BH9 test set. The errors are nearly always within chemical accuracy (4 kJ mol) along with a significant time benefit. In rare cases, larger errors are observed. These are analyzed by comparison of SC and iterative perturbative triples, of different ML thresholds, and of ML and single-level schemes. A beneficial error cancelation between DLPNO and ML contributions is also observed in several cases.

In this work, a computational protocol has been developed to predict the ligand-based low-lying excited-state energies of Eu coordination compounds with antenna ligands. A computational strategy, based on density functional theory (DFT) and time-dependent density functional theory (TD-DFT), has been developed using compounds with reliable structural and spectroscopic experimental data as a reference set. This approach aims to predict both the geometry and energy of the lowest-excited triplet state, critical factors influencing the efficiency of the antenna effect and energy transfer to the Eu ion. The model not only shows the ability to replicate available experimental data at a relatively low computational cost, but also accurately predicts triplet-state energies for compounds that have not been included in the training set. This work is a first step toward the development of an affordable method for accurate predictions of the quantum yield of lanthanide-based complexes to assess their potential application as down-shifting spectral converters in solar cells.

The electrodics of bismuth-tin (Bi-Sn) bimetallic alloy has been investigated toward the electrocatalytic reduction of CO to formate (CORR). Bi-Sn with varied compositions and morphologies is electrochemically deposited on a gold-substrate, including a gold rotating disk electrode (RDE) and gold ultramicroelectrode (UME). The powder X-ray diffraction and differential thermal calorimetry analyses confirmed the formation of a Bi-Sn bimetallic alloy with traces of their corresponding oxides. X-ray photoelectron spectroscopy analysis further corroborates the presence of bismuth oxide on the catalyst surface. The primary investigation of the electrocatalytic performance of Bi-Sn alloy toward CORR has been done using cyclic and linear sweep voltammetry. The mechanistic aspects of charge transfer have been obtained from the Tafel analysis of the RDE and UME data. The extracted Tafel slope, transfer coefficient (α) and standard rate constant (k) underline the two-electron transfer pathway involving the formation of the anion radical as a key intermediate. The nuclear magnetic resonance spectroscopy of the electrolysis products confirms formate as the major reduction product, with a faradaic efficiency (FE) of 85.3 %. The high FE toward CORR is attributed to the synergistic interaction between Bi and Sn within the porous alloy framework.

This article ventures into the interactions between DNA and theophylline (Th), a biologically active xanthine derivative with pharmacological properties, using in-silico methods. Density functional theory calculations were used to assess the interactions between theophylline and natural nucleobases: adenine (A), guanine (G), cytosine (C), and thymine (T). Different interacting orientations, namely the planar hydrogen-bonded conformations and the vertically stacked geometries between theophylline and nucleobases have been investigated by evaluating the binding energies of the dimeric structures. The strength of hydrogen bonding between theophylline and nucleobases is found to be stronger compared to π-π stacking interactions, and hence, it is unlikely that theophylline would invade the DNA duplex and insert between nucleobases. Classical molecular dynamics simulations have been performed to gauge the interactions between theophylline and a DNA double helix. Theophylline is indeed observed to interact with DNA via hydrogen bonding rather than π-π stacking, keeping the DNA intact and eliminating any potential damage. Therefore, the adverse drug reactions of theophylline do not originate from the perturbation of DNA, and are of different origins. This research lays a solid groundwork and builds a deep understanding for future investigations aimed at studying interactions between theophylline and biomolecules.

Calcium boranate (Ca(BH)) is synthesized using wet chemistry metathesis reactions resulting in mixtures of both α- and β-Ca(BH), with the β phase being the main component. The drying procedure reveals high kinetic stability of the high temperature β polymorph, which is in contrast to the expectations based on the literature. The molar heat capacity function of β-Ca(BH) is determined between 2 and 525 K using different calorimeters, a Physical Property Measurement System applying the relaxation method in the low temperature range and a Calvet-DSC for the high temperature range. From these values the absolute standard entropy at 298.15 K for β-Ca(BH) is calculated as S(298.15 K) = (117.4 ± 4.1) J mol K. Taking the value of the enthalpy of formation from the literature, the Gibbs energy functions are calculated and the decomposition and rehydrogenation behavior of the compound is discussed.

Hydrogen gas is not only an essential industrial raw material but also an important clean energy. The hydrogen production by methanol steam reforming (MSR) has attracted much attention due to its mild reaction conditions and high hydrogen yield. Herein, the MSR reactions on CuZnO cluster are explored using theoretical calculations. It is found that the adjacent Cu and Zn atoms in CuZnO cluster play the synergistic roles in the MSR reaction. Specifically, the reaction starts with the adsorption of HO and CHOH on the Zn atoms. Then, the adsorbed CHOH and HO dehydrogenate, and the produced oxygen-containing intermediates (CHO* and *OH) remain adsorbed on the Zn atoms. The dissociated H atoms migrate to the nearby Cu atoms. In their subsequent dehydrogenation, this rule is still followed. With the participation of HO, CHO* combines with OH* to form CHOOH*, followed by consecutive dehydrogenation to produce CO and H. Moreover, the formate (HCOO*) pathway is the least energy-demanding pathway compared with the carboxyl (COOH*) pathway. The synergistic roles of adjacent Cu and Zn atoms in CuZnO cluster may provide insight into the structure-activity relationship of CuZnO interfacial sites in related MSR catalysts.