Density Functional Theory Calculations Research Articles

Globin ferryl species: what is the nature of the protonation event at pH < 5?

The ferryl state in globins has previously been reported to undergo a protonation event below pH 5, as assessed using pH jump experiments with stopped-flow UV-Vis spectroscopy. This protonation entails hypsochromic shifts in the α and β bands (~ 20 to 40nm) and an ~ 10nm reduction in the energy difference between these two bands. We now report that in Mb this event is also characterized by a hypsochromic shift in the Soret band (~ 5nm). No similar shifts in Soret, α, and β bands are seen upon the denaturation of ferryl Mb with guanidine-suggesting that the spectroscopic changes in ferryl Mb at pH < 5 are not caused by changes in the solvent exposure or in hydrogen bonding around the ferryl unit. Under the same denaturing conditions (pH jump below pH 5, and/or guanidine), ferric-aqua and ferrous-oxy Mb show no spectral changes of the order seen in the ferryl pH jump experiments. Together, these observations suggest that the protonation event is localized on the iron-bound oxygen atom, as opposed to somewhere on a hydrogen-bonding partner. Time-dependent density functional theory (TD-DFT) calculations were not able to systematically predict the UV-Vis spectra of the heme to the level of detail needed to interpret the experimental findings in this study.

Highly Stable Lanthanide-Organic Frameworks Based on {Ln6O8} Clusters with Photocatalytic Reduction of CO2 to CO.

Metal-organic frameworks (MOFs) with adjustable structures, diverse chemical functionalities, and excellent CO2 capture ability have shown important potential application in the photocatalytic reduction of CO2 to valuable fuel to curb the energy crisis. In this work, a series of new isostructural lanthanide-organic frameworks based on hexanuclear {Ln6O8} clusters, {(DMA)2 [Ln6(μ3-OH)8(H2O)6(SBTC)3]}n (Ln-MOFs, Ln = Eu, Dy, Gd, Tb, Yb; H4SBTC = 5,5'-(ethene-1,2-diyl) di-isophthalic acid; DMA = dimethylamine cation) were synthesized by the solvothermal method. Ln-MOFs were metal-organic frameworks formed by {Ln6(μ3-OH)8} clusters and poly(carboxylic acid) ligands H4SBTC, which exhibited excellent photocatalytic properties for the reduction of CO2 to CO. Among these Ln-MOFs, the production rate of photocatalytic reduction of CO2 to CO by Eu-MOF was 663.00 μmol·h-1·g-1 and the selectivity reached 94.2%, utilizing [Ru(bpy)3]Cl2·6H2O as photosensitizers. Experimental characterizations and density functional theory (DFT) calculations unveiled that the effective charge separation, strong CO2 binding affinity, weak H2O adsorption energy, as well as low reaction energy barriers for the *COOH intermediates over Eu-MOF play an important role in possessing superior photoactivity. This study provides insights into the field of Ln-MOF materials for efficient photocatalytic CO2 reduction and conversion applications.

Theoretical and Experimental Investigation of Indazole Derivatives as Corrosion Inhibitors for Copper in Acidic Medium.

To explore the slow-release potential of indole oxygen-containing functional group derivatives in acidic media in order to reduce their negative impact on the environment. We investigated the corrosion inhibition effect of 5-Methoxy-indazole (MIA) and Methyl 1H-indazole-5-carboxylate (MIC) on copper in H2SO4 through electrochemical testing, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) analysis, and theoretical calculations. Research has found that MIA and MIC exhibit excellent corrosion inhibition performance, with MIA achieving an efficiency of up to 91.04%. SEM observed that MIA and MIC formed a protective film on the copper surface, effectively isolating the corrosive medium. The adsorption behavior conforms to the Langmuir model, indicating the coexistence of chemical and physical adsorption. Density functional theory calculations (DFT) and molecular dynamics simulations (MD) further revealed the corrosion inhibition mechanism of imidazole derivatives, emphasizing their potential for application in acidic media. These results not only elucidate the corrosion inhibition effect of imidazole compounds, but also provide new ideas for corrosion control in acidic environments.

Intrinsic Localized Excitons in MoSe2/CrSBr Heterostructure.

Despite extensive studies on magnetic proximity effects, the fundamental excitonic properties of the 2D semiconductor-magnet heterostructures remain elusive. Here, the presence of localized excitons in MoSe2/CrSBr heterostructures is unveiled, represented by a new photoluminescence emission feature, X*. Our findings reveal that X* originates from excitons confined by intrinsic defects in the CrSBr layer. Additionally, the degrees of valley polarization of the X* and trion peaks exhibit opposite polarities under a magnetic field and closely correlate with the magnetic order of CrSBr. This is attributed to spin-dependent charge transfer across the heterointerface, supported by density functional theory calculations which reveal a type-II band alignment. Furthermore, the strong in-plane anisotropy of CrSBr induces unique polarization-dependent responses in MoSe2 emissions. This study highlights the crucial role of defects in shaping excitonic properties and offers valuable insights into spectrally resolved proximity effects in semiconductor-magnet van der Waalsheterostructures.

Interfacial Engineering to Fabricate Nanoporous FeMo Bimetallic Nitride for Enhanced Electrochemical Ammonia Synthesis.

The electrochemical N2 reduction reaction (NRR) currently represents a green and sustainable approach to ammonia production. However, the further progress of NRR is significantly hampered by poor catalytic activity and selectivity, necessitating the development of efficient and stable electrocatalysts. Herein, a nanoporous Fe-Mo bimetallic nitride (Fe3N-MoN) is synthesized using a molten-salt preparation method. This catalyst demonstrates notable NRR performance, achieving a high NH3 yield rate of 45.1µgh-1mg-1 and a Faradaic efficiency (FE) of 26.5% at -0.2V (vs RHE) under ambient conditions. Detailed experimental studies and density functional theory (DFT) calculations reveal that the fabricated interface between Fe3N and MoN effectively modulates the surface electronic structure of the catalyst. The interface induces an increase in the degree of electron deficiency at the nitrogen-vacancy sites on the catalyst surface, allowing N2 molecules to occupy the nitrogen vacancies more easily, thereby promoting N2 adsorption/activation during the NRR process. Consequently, the Fe3N-MoN catalyst exhibits outstanding NRR activity. The insights gained from fabricating the Fe3N-MoN interface in this work pave the way for further development of interfacial engineering to prepare high-efficient electrocatalyst.

Identification of dimethyl 2,2’-((methylenebis(2-(2H-benzo[d][1,2,3]triazol-2-yl)-4-(2,4,4-trimethylpentan-2-yl)-6,1phenylene))bis(oxy))diacetate (TAJ4) as antagonist of NEK-Family: a future for potential drug discovery

The purpose of the current study was to analyze and validate the existing gap in knowledge, by conducting a differential expression analysis and validation of NEK6, NEK7, and NEK9 in breast, cervical, and glioblastoma cancer and targeting these proteins through development of novel site specific inhibitor with favorable pharmacokinetic and safety profile, using open-source databases. The analysis revealed that the targeted kinases were overexpressed in all three types of cancer. Their expression was significantly linked to overall survival rates, which suggests that they play a major role in the development and progression of these cancers. After, having the prognostic importance of These findings provided a rationale for synthesizing novel compound i.e., dimethyl 2,2’-((methylenebis(2-(2H-benzo[d][1,2,3]triazol-2-yl)-4-(2,4,4-trimethylpentan-2-yl)-6,1phenylene))bis(oxy))diacetate (TAJ4)), capable of effectively targeting these proteins using in-vitro cytotoxicity assays and comprehensive computational approaches. Then the inhibitory potential of TAJ4 was evaluated against cell lines of the respective cancers (HeLa cells, MCF-7 cells, and Vero cells). The growth inhibitory values (GI50) suggested that TAJ4 exhibited strong inhibitory potential towards MCF-7 cells (GI50 = 3.18 ± 0.11 µM) in comparison to the HeLa cell line (GI50 = 8.12 ± 0.43 µM), surpassing that of standard drugs. Furthermore, in-silico investigations, including density functional theory (DFT) calculations and molecular docking studies, revealed a substantial reactivity profile of TAJ4, with promising molecular interactions against NEK7, NEK9, TP53, NF-KAPPA-B, and caspase-3 proteins. Further investigation using in-vitro and in-vivo approaches is recommended to fully establish the therapeutic efficacy and safety profile of TAJ4.

Excitation Wavelength Regulated Dynamic Luminescence in Bi/Sb co‐Doped Tin Halide for Encrypted Information Transmission and High‐Sensitivity Wavelength Sensor

AbstractThe coordination structure of Sb3+ within the host lattice critically influences its photophysical properties, sparking interest in luminescent metal halides with multiexciton emissions. Furthermore, the multi‐coordination lattice structure of Sb3+ dynamically emits light with excitation wavelength, highlighting the potential of Sb3+ ions in tuning luminescence and developing advanced optoelectronic materials. Herein, Sb3+ ions are successfully doped into Cs2SnCl6, and the obvious excitation wavelength‐dependent emission of Cs2SnCl6: Sb at room temperature is observed. To explain this phenomenon, density functional theory (DFT) calculations and time‐resolved spectra are conducted to confirm that the emission originated from two luminescence centers associated with the [SbCl6]3− and [SbCl5]2− coordination. Based on the tunable emission of Cs2SnCl6: Sb and the effective electron transfer between two triplet self‐trapped exciton states induced by Bi3+ and Sb3+, a pixelated code for information encryption is designed. The encoded patterns exhibit color changes under different UV wavelengths, enabling secure and straightforward information encryption. Furthermore, a sensitive UV wavelength sensor is prepared based on Cs2SnCl6: Bi/Sb, exploiting the monotonic relationship between chromaticity coordinates and wavelength, achieving a resolution superior to previously reported wavelength sensors. This study marks a substantial step toward advancing the multifunctional application of lead‐free metal halides.

Hydration Pattern of Ionic Liquids in the Stabilization of Insulin Dimer: A Computational Perspective

AbstractCholine [Cho]‐based ionic liquids (ILs) are biodegradable and soluble and have shown strong application in the protein stabilization and drug delivery. In this work, the stability of the insulin dimer is investigated in the presence of [Cho]‐based ILs containing three distinct anions (i.e., acetate [OAc], taurate [Tau], and geranate [Ger]). Molecular dynamics (MD) simulations and density functional theory (DFT) calculations explore insulin's stability and structure in the presence of ILs. MD analyses reveal that the insulin dimer is stabilized by non‐covalent interactions, with hydrogen bonds and anions in ILs playing key roles. Among them, [Cho][OAc] ILs show significantly better stabilization than other anions.This is due to the hydration patterns of acetate anion, which can be compared to Hofmeister series and chemical agent effects (i.e., kosmotrope and chaotrope). Further, non‐covalent interactions index and electron density analyses from the atoms‐in‐molecules theory approach are carried out to quantify the strength of non‐covalent interaction in ILs with water clusters (Wn, n = 0–6). Analyses show the significance of water molecules in the stabilization of insulin dimer in the presence of [Cho]‐based ILs. The study elucidates the role of ILs formulation concerning insulin dimers to improve the transdermal and oral drug delivery systems.

Regulating the Positive Localized Electric Field in Mixed Matrix Membranes by Charge Reversal of ILs‐COF for Boosting CO2 Separation

AbstractCovalent organic frameworks (COFs), characterized by their high porosity and stability, hold great potential for applications in gas separations. However, achieving precise size sieving without hindering the gas diffusion rate is challenging. This study presents a novel approach to establishing tunable localized electric fields in COF channels to achieve efficient CO2 separation in Pebax‐based mixed matrix membranes (MMMs). Different charge densities of the localized electric field are achieved by the host–guest interaction between COF and varying charged ionic liquids (ILs). Remarkably, the MMM with a positive localized electric field attains the optimal CO2/CH4 separation performance with a significantly enhanced permeability (≈38%) and selectivity (≈99%), surpassing the Robeson upper bound. Through density functional theory (DFT) calculations, the enhanced CO2/CH4 selectivity of MMM is due to the “sieving effect” of a positive localized electric field on CO2 over CH4. Specifically, the negatively charged O atom in CO2 exhibits stronger electrostatic interaction than the positively charged H atom of CH4. Therefore, the strategy of regulating the localized electric field can be employed as an efficient design for CO2 separation in MMMs.

Tuning optical and electronic properties of indanthrene derivatives with electron-withdrawing groups (-Cl, -NO₂ and -C≡N) for enhanced organic solar cell performance: a DFT approach

Abstract In this study, we focused on improving the electronic and optical properties of the reference compound indanthrene (R) by introducing electron-withdrawing groups (−Cl, −C≡N, −NO₂). density functional theory and time-dependent density functional theory calculations were performed using Gaussian 16 software to study indanthrene derivatives as electron acceptor materials. The electronic and optical properties of the designed molecules (M1-M8) were investigated through frontier molecular orbital analysis, UV-visible absorption spectra, density of states, and transition density matrix analysis, utilizing GaussView 6.0 and Multiwfn 3.8 software. The designed molecules exhibit absorption across the entire visible spectrum, with maxima extending up to ~737 nm. Their electron affinity values range from 3.0 to 4.0 eV, surpassing the fullerene-based acceptor material. Among the designed molecules, M5 stands out with superior photovoltaic parameters, including a narrow optical band gap (~1.68 eV), exciton binding energy (0.25 eV), higher electron affinity (3.35 eV), an extended excited state lifetime (17.0 ns) owing to its low electron and hole reorganization energies (λe ~ 0.190 eV, and λh ~ 0.134 eV), and improved short-circuit current density of ~ 15.7 mA/cm². The photovoltaic parameters and power conversion efficiency were assessed using the Scharber and Alharbi models. The calculated device parameters, including light harvesting energy and photovoltaic characteristics (Voc, FF, Jsc, and PCE), suggest that these molecules, with electron-withdrawing groups, show great potential for use as acceptors in organic solar cells, particularly in terms of stability and power conversion efficiency. Notably, M2 and M5, with their PCE values exceeding 16%, emerge as outstanding candidates for device performance, impressively outperforming the other designed molecules.

Unveiling Active Al3+ Sites for Ethanol Dehydration on γ-Al2O3 with Solid-State Nuclear Magnetic Resonance Spectroscopy.

γ-Al2O3 is a crucial catalyst widely used in industrial alcohol dehydration processes. However, the specific nature of its active sites has remained unclear. In this study, we utilize two-dimensional heteronuclear correlation solid-state nuclear magnetic resonance and density functional theory calculations to uncover the active Al sites on the surface of γ-Al2O3 that facilitate ethanol dehydration. We show the formation of stable pentacoordinated AlV-ethanol complexes upon the adsorption of ethanol on the tetracoordinated AlIV sites. This interaction significantly enhances synergy with adjacent AlV-OH sites, resulting in a marked reduction of the activation energy barrier for ethene production. Furthermore, we reveal an interchange between AlIV and AlV-OH species, allowing hexacoordinated AlVI-OH sites to participate in the dehydration pathway through the migration of ethanol between these coordination sites.

Boosting Formate Production in Electrocatalytic CO2 Reduction on Bimetallic Catalysts Enriched with In-Zn Interfaces.

We present an effective strategy for developing the dispersing strong-binding metal In on the surface of weak-binding metal Zn, which modulates the binding energy of the reaction intermediates and further facilitates the efficient conversion of CO2 to formate. The In-Zn interface (In-Zn2) benefits from the formation of active sites through favorable orbital interactions, leading to a Faradaic efficiency of 82.7% and a formate partial current density of 12.39 mA cm-2, along with stable performance for over 15 h at -1.0 V versus the reversible hydrogen electrode. Both in situ Fourier transform infrared spectroscopy and density functional theory calculations show that the In-Zn bimetallic catalyst can deliver superior binding energy to the *OCHO intermediate, thereby fundamentally accelerating the conversion of CO2 to formate. In addition, the exposed bimetallic interface promotes efficient capture and activation of CO2 molecules and the dynamics within the In-Zn catalyst significantly reduce the energy barrier associated with the generation of HCOO-, thus augmenting the selectivity and catalytic activity for formate generation.

Dual‐Active Centers Linked by Oxygen Transfer for Enhancing Proximity‐Orientation Effect of Nanozyme

AbstractProximity‐orientation effects (POE) are essential for enzymes, as the spatial arrangement and orientation of catalytic sites strongly influence substrate binding and enhance catalysis. However, nanozymes often face limitations due to weak POE arising from uniform catalytic interfaces. Herein, Co atoms are incorporated into the lattice of Pt‐based nanozymes, exploiting differences in electron configuration and atomic radius between transition metals and noble metals. This integration induced lattice distortion formed new catalytic sites, and restricted the transport path, thereby enhancing the POE. Such transition metal‐doped alloy nanozyme (TANzyme) can be functioned as a self‐cascading nanozyme with artificial catalase‐oxidase activity. Density functional theory calculations demonstrated that the Pt site selectively decomposed H2O2 into H2O and O2, while the Co site specifically adsorbed O2 and conversed into superoxide anions, so an oxygen transfer path to connect dual‐active centers not only increased the POE but also improved catalytic specificity. Additionally, by leveraging the efficient catalytic property of TANzyme, a visual origami‐based sensing strategy is developed for the cascade detection of H2O2, nucleic acids, and marine toxins. This strategy highlighted the pivotal role of POE in enhancing the catalytic specificity of nanozymes, mimicking natural POE in enzymes, and providing a solution to design next‐generation nanozymes.

Thermal degradation of tertiary amine for CO2 capture: Structure–activity relationships and density functional theory calculations

AbstractAqueous amine solution is a promising absorbent for CO2 capture, yet irreversible reaction, that is, degradation can happen for amine and leads to performance decrease and many operating difficulties. Despite numerous research on reaction between amine and CO2 for absorption, the reaction of amine degradation is not fully understood, especially for tertiary amine which is a vital component in constructing high‐performance CO2 absorbent. Considering the variety of tertiary amines, this article studied the thermal stability of five tertiary amine solutions at different temperatures to mimic the regeneration condition. The density functional theory (DFT) calculation was applied to reveal the degradation mechanism. The alkylation reaction that triggered the degradation of tertiary amine was deemed as the limiting step. Then the molecular simulation method was extended to 12 tertiary amines, aiming to further illustrate the influence of molecular structure on the alkylation reaction. These results provide basic data and theoretical guidance for developing the anti‐degradation CO2 absorbent.

Photochemical and Collision-Induced Cross-Linking of Lys, Arg, and His to Nitrile Imines in Peptide Conjugate Ions in the Gas Phase.

We report a study of internal covalent cross-linking with photolytically generated diarylnitrile imines of N-terminal arginine, lysine, and histidine residues in peptide conjugates. Conjugates in which a 4-(2-phenyltetrazol-5-yl)benzoyl group was attached to C-terminal lysine, that we call RAAA-tet-K, KAAA-tet-K, and HAAA-tet-K, were ionized by electrospray and subjected to UV photodissociation (UVPD) at 213 nm. UVPD triggered loss of N2 and proceeded by covalent cross-linking to nitrile imine intermediates that involved the side chains of N-terminal arginine, lysine, and histidine, as well as the peptide amide groups. Cross-linking yields were determined from UVPD-MS2 measurements as 67%, 66%, and 84% for RAAA-tet-K, KAAA-tet-K, and HAAA-tet-K ions, respectively. CID-MS3 of the denitrogenated ion intermediates from RAAA-tet-K, KAAA-tet-K, and HAAA-tet-K indicated overall cross-linking yields of 80%, 89%, and 80%, respectively. The nature of the cross-linking reactions and cross-link structures were investigated for RAAA-tet-K by high-resolution cyclic ion mobility mass spectrometry that identified precursor ion conformers and multiple dissociation products. All sequences were subjected to conformational analysis by Born-Oppenheimer molecular dynamics, and energy analysis by density functional theory calculations with M06-2X/def2qzvpp that provided relative and dissociation energies for several cross-link structural types. The cross-linking reactions were substantially exothermic, driving the efficient conversion of nitrile-imine intermediates to cyclic products. The principal steps in covalent cross-linking involved proton transfer onto the nitrile imine group accompanied by nucleophilic attack by the peptide side-chain and amide groups. Blocking the proton transfer and nucleophile resulted in a loss of cross-linking abilities.

Analysis of polaron pair lifetime dynamics and secondary processes in exciplex driven TADF OLEDs using organic magnetic field effects

Magnetic field effects (MFEs) in thermally activated delayed fluorescence (TADF) materials have been shown to influence the reverse intersystem crossing (RISC) and to impact on electroluminescence (EL) and conductivity. Here, we present a novel model combining Cole–Cole and Lorentzian functions to describe low and high magnetic field effects originating from hyperfine coupling, the g mechanism, and triplet processes. We applied this approach to organic light-emitting devices of third generation based on tris(4-carbazoyl-9-ylphenyl)amine (TCTA) and 2,2′,2″-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi), exhibiting blue emission, to unravel their loss mechanisms. The quality of the regression function was evaluated using k-fold cross-validation. The scoring was compared to various alternative fitting functions, which were previously proposed in literature. Density functional theory calculations, photoluminescence, and electroluminescence studies validated the formation of a TADF exciplex system. Furthermore, we propose successful encapsulation using a semi-permeable polymer, showing promising results for magnetic field sensing applications on arbitrary geometry. This study provides insights into the origin of magnetic field effects in exciplex-TADF materials, with potential applications in optoelectronic devices and sensing technologies.

Influence of strain and point defects on the electronic structure and related properties of (111)NiO epitaxial films

Abstract (111)NiO epitaxial films are grown on c-sapphire substrates at various growth temperatures ranging from room temperature to 600 ∘ C using pulsed laser deposition technique. Two series of samples, where different laser fluences are used to ablate the target, are studied here. Films grown with higher laser fluence, are found to be embedded with Ni-clusters crystallographically aligned with the (111)NiO matrix. While the layers grown with lower laser energy density exhibit p-type conductivity, especially at low growth temperatures. X-ray diffraction study shows the coexistence of biaxial compressive and tensile hydrostatic strains in these samples, which results in an expansion of the lattice primarily along the growth direction. This effective uniaxial expansion ε ⊥ increases with the reduction of the growth temperature. Band gap of these samples is found to decrease linearly with ε ⊥ . This result is validated by density functional theory calculations. Experimental findings and the theoretical study further indicate that V Ni + O I and V O + N i I complexes exist as the dominant native defects in samples grown with Ni-deficient (low laser fluence) and Ni-rich (high laser fluence) conditions, respectively. P-type conductivity observed in the samples grown in Ni-deficient conditions is more likely to result from V Ni + O I defects than Ni-vacancies ( V Ni ).

Fundamental understanding of quantum confinement effect on gate oxide reliability for gate-all around field-effect transistor

Gate oxide reliability has become a significant concern for emerging technology nodes, particularly as transistors continue to scale down. Quantum confinement effects in nano-scaled devices complicate the trapping dynamics near the interface. Although these behaviors can be modeled using density-functional theory (DFT) and Marcus theory, a more efficient method is essential for characterizing critical reliability issues at the nano-device level. This paper presents a pioneering numerical study that employs a Bohm potential and Marcus theory, examining carrier concentration decay near the channel/oxide interface to evaluate the charge-trapping process using density-gradient coupled Poisson equations. This approach incorporates vital quantum corrections to classical studies. Key physics-based parameters are initially derived from DFT calculations and subsequently calibrated against experimental data. Our findings indicate that charge trap rates decrease with carrier density at the interface, ultimately affecting the device's threshold voltage shift.

Platinum Compound on Gold–Magnesia Hybrid Structure: A Theoretical Investigation on Adsorption, Hydrolysis, and Interaction with DNA Purine Bases

Cisplatin-based platinum compounds are important clinical chemotherapeutic agents that participate in most tumor chemotherapy regimens. Through density-functional theory calculations, the formation and stability of the inorganic oxide carrier, the mechanisms of the hydrolysis reaction of the activated platinum compound, and its binding mechanism with DNA bases can be studied. The higher the oxidation state of Pt (II to IV), the more electrons transfer from the magnesia–gold composite material to the platinum compound. After adsorption on the composite carrier, 5d←2p coordination bonds of Pt-N are strengthened. For flat and oblique adsorption modes of cisplatin, there is no significant difference in the density of states of the gold and magnesium oxide film, indicating the maintenance of the heterojunction structural framework. However, there are significant changes in the electronic states of cisplatin itself with different adsorption configurations. In the flat configuration, the band gap width of cisplatin is larger than that of the oblique configuration. The Cl-Pt bond range in the Pt(III) compound shows a clear charge reduction on the magnesia film, indicating the Cl-Pt bond is an active site with the potential for decomposition and hydrolysis. The substitution of chloride ions by water can lead to hydrolysis products, enhancing the polarization of the composite and showing strong charge separation. The hydrolysis of the free platinum compound is endothermic by 0.309 eV, exceeding the small activation energy barrier of 0.399 eV, indicating that hydrolysis of this platinum compound is easily achievable. ADME (absorption, distribution, metabolism, and excretion) prediction parameters indicate that hydrolysis products have good ESOL (Estimated SOLubility) solubility and high gastrointestinal absorption, consistent with Lipinski’s rule. During the coordination reaction process, there are significant changes in the distribution of frontier molecular orbitals, with the HOMO (highest occupied molecular orbital) of the initial state primarily located on the purine base, providing the possibility for electron transfer to the empty orbitals of the platinum compound in the LUMO (lowest unoccupied molecular orbital). The HOMO and HOMO-1 of the transition state and product are mainly distributed on the platinum compound, indicating clear electron transfer and orbital rearrangement. The activation energy barrier for the purine coordination reaction with the hydrolysis products is reduced to 0.61 eV, and the dipole moment gradually decreases to 6.77 Debye during the reaction, indicating a reduction in the system’s charge separation and polarization. This contribution is anticipated to provide a new theoretical clue for developing inorganic oxide carriers of platinum compounds.

Room-temperature in-plane ferromagnetism in Co-substituted Fe5GeTe2 investigated by magnetic X-ray spectroscopy and microscopy

Abstract The exploration of two-dimensional (2D) van der Waals ferromagnets has revealed intriguing magnetic properties with significant potential for spintronics applications. In this study, we examine the magnetic properties of Co-doped Fe5GeTe2 using X-ray photoemission electron microscopy (XPEEM) and X-ray magnetic circular dichroism (XMCD), complemented by density functional theory (DFT) calculations. Our XPEEM measurements reveal that the Curie temperature (T C) of a bilayer of (CoxFe1-x)5-δGeTe2 (with x = 0.28) reaches ∼300 K — a notable enhancement over most 2D ferromagnets in the ultrathin limit. Interestingly, the TC shows only a small dependence on film thickness (bulk T C ≈ 340 K), in line with the observed in-plane magnetic anisotropy and robust in-plane exchange coupling. XMCD measurements indicate that the spin moments for both Fe and Co are significantly reduced compared to the theoretical values. These insights highlight the potential of Co-doped Fe5GeTe2 for stable, high-temperature ferromagnetic applications in 2D materials.