Metallocenes are a wide family of organometallic compounds, in which two cyclopentadienyl ligands 'sandwich' a metal ion, M( r)5 -C5 R5 )2 , and have considerable potential for use as components in molecular electronics applications. Here we have studied the electronic transport properties of the matallocenes MCp2 (M = V, Cr, Mn, Fe, Co, Ni, Ru; Cp = r)5 -C5 H5 ) and MCp*2 (M = Mn, Fe, Co; Cp* = r)5 -C5 Me5 ). Molecular junctions have been fabricated using either two gold, or one gold and one graphene electrode(s), giving rise to single-molecule conductance values of the order of -4 to -3 log( G / G0 )) depending on both the nature of the metallocene and the electrode materials. Calculations on model junctions at the density functional theory level of theory reveal significant charge transfer from the metallocene to the junction electrodes and changes in the nature of the primary charge transport pathways in response to the nature of the metal, supporting ligands, molecular oxidation state and electrode composition. (c) 2026 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Polycyclic aromatic hydrocarbons (PAHs) are persistent environmental pollutants associated with significant ecological and human-health risks. In this work, the adsorption and sensing potential of B₃O₃ nanoflakes toward representative PAHs, namely benzene, naphthalene, anthracene, and pyrene, was investigated using a multilevel computational approach combining density functional theory (DFT), Monte Carlo simulations, and quantum chemical analyses. The calculated adsorption energies, ranging from approximately − 14 to − 30 kcal mol⁻1, indicate favorable physisorption, with stronger adsorption observed for larger and more π-conjugated PAHs due to enhanced dispersion-assisted π-π interactions and increased adsorbate–surface contact area. Adsorption induces notable electronic perturbations in the B₃O₃ nanoflake, including reductions in the HOMO–LUMO gap, Fermi-level shifts, and dipole-moment changes, suggesting a possible electronic response toward PAH adsorption. QTAIM, NBO, Mulliken charge, and RDG/NCI analyses confirm that the interactions are dominated by noncovalent van der Waals forces, weak π-surface interactions, and minor interfacial polarization, without evidence of covalent bond formation. Recovery-time estimates suggest fast desorption for benzene and moderate desorption for naphthalene, whereas stronger adsorption of anthracene and pyrene may require external stimulation for efficient sensor regeneration. Overall, the results identify B₃O₃ nanoflakes as promising theoretical candidates for PAH adsorption and possible sensing applications, although further DOS/PDOS, periodic electronic-structure, and transport-level studies are required to validate practical sensor performance.

The current study was carried out by determining structural and energetic parameters to theoretically validate the experimental results of the adsorption efficiency of amine-functionalized porous carbon for the elimination of Cu 2+ ions and Pb 2+ and detail the reaction mechanism in the aqueous medium. The Density Functional Theory calculations, molecular dynamics, and Monte Carlo simulations were used to investigate the adsorption enhancement mechanism. The calculations were performed using the Dmol3 module of the Materials Studio program (MatS) using the exchange-correlation function M-11L2. DFT calculations were determined for porous carbon (PC) and porous carbon functionalized by ethylene diamine (PC-ED). Indeed, this study aims to reveal the functionalization influence on improving the adsorption efficiency of Cu 2+ and Pb 2+ by porous carbon (PC). Overall, the study attempts to explain the experimental results of the improved interactivity of porous carbon functionalized by ethylene diamine concerning Cu 2+ and Pb 2+ ions, compared to the reactivity of these ions with the group carboxyl characterizes the porous carbon (PC). The Molecular dynamics and Monte Carlo simulations were used to clarify the interactions between Cu 2+ or Pb 2+ ions and porous carbon modelled in the presence or absence of ethylene diamine (PC–ED) function. Hence, the theoretical study showed that the presence of ethylene diamine (C 2 H 4 (NH 2 ) 2 ) m forms more ligands towards the ions of metal M 2+ with the interaction bounds lower than ≤ 2.5 Å. The same result is shown by the small adsorption energy obtained in the range of -1140 to -200 kcal/mol for and -1200 to -600 kcal/mol for Pb 2+ and Cu 2+ , respectively. Therefore, more adsorption of Cu 2+ and Pb 2+ ions. The theoretical results obtained agree with the experimental results.

Although essential amino acids play a critical role in biological and medical fields, only a limited number of computational studies on their interaction with nanocages have been reported in the literature. This study explores the potential of Be12O12 nanocage for detecting amino acids, specifically glycine, valine, leucine, methionine, threonine, and phenylalanine. The adsorption of these amino acids onto the Be12O12 structure is investigated using Density Functional Theory (DFT) calculations, employing the B3LYP-D3/def2-TZVP level of theory. The calculated adsorption energies for Gly_Be12O12, Val_Be12O12Leu_Be12O12, Met_Be12O12, Thr_Be12O12and Phe_Be12O12₂ in water phase (gas) are − 104.3 (-133.8) kJ·mol−1, -108.1 (-137.7) kJ·mol−1, -109.4 (-139.4) kJ·mol−1, -121.4 (-169.5) kJ·mol−1, -120.2 (-150.5) kJ·mol−1, and − 117.7 (-151.9), respectively. To characterize the nature of interactions in the studied complexes, several analyses were performed, including Interaction Region Indicator (IRI), charge decomposition analysis (CDA), and energy decomposition analysis (EDA). Additionally, quantum electronic parameters, such as the density of states (DOS), HOMO-LUMO gaps, and percentage change in the HOMO-LUMO gap, along with geometric properties, were calculated to assess the stability and structural characteristics of the complexes. The results show that Met_Be12O12, Thr_Be12O12, and Phe_Be12O12 exhibit higher binding energies than the other complexes, indicating a stronger interaction with the Be12O12 nanocage. The adsorption analysis of multiple amino acid molecules indicates that the Be12O12 nanocage exhibits an optimal adsorption capacity, with the ability to adsorb up to four molecules of leucine and valine, three molecules of phenylalanine and glycine, and a single molecule of methionine and threonine. This study provides theoretical insights into the interactions between Be12O12 and amino acids, enhancing the understanding of their nature, and contributing therefore to the advancement of biosensor development for amino acid detection.

Fenethylline, commonly known as Captagon, is a stimulant with amphetamine-like properties that has gained notoriety due to its widespread illicit use, particularly in conflict zones. Its ease of synthesis and environmental persistence necessitate effective remediation strategies. This study investigates the adsorption potential of graphene (G) for Captagon removal using a multi-scale computational approach, including density functional theory (DFT), Monte Carlo (MC), and molecular dynamics (MD) simulations. The interaction between Captagon and graphene was analyzed in both perpendicular and parallel adsorption configurations. The results indicate that the parallel orientation exhibits superior adsorption stability, with an adsorption energy of –51.15 kcal mol⁻1, primarily driven by π–π stacking interactions. Frontier molecular orbital (FMO) analysis further reveals significant alterations in graphene's electronic properties upon Captagon adsorption, with noticeable shifts in the Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO) energy levels and bandgap (Egap). The molecular dynamics simulations confirm the stability of the Captagon-graphene complex, reinforcing graphene's potential as a viable adsorbent. These findings highlight graphene's efficiency in Captagon removal, suggesting its broader applicability in water purification and environmental remediation strategies.

This study investigates the optimization of (2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl)phosphonic acid (MeO-2PACz) ultrathin self-assembled monolayers (SAMs) on indium tin oxide (ITO) substrates, which serve as templates for the controlled growth of methylammonium lead iodide perovskite films. The influence of solvent composition and deposition method on the structural properties of the SAM and its effect on the perovskite morphology are investigated by using polarization modulation infrared reflection absorption spectroscopy and X-ray photoelectron spectroscopy. Our results show that the addition of 2% toluene to an ethanol solution during spin coating results in a denser, more organized SAM, with molecules exhibiting a 40 degrees tilt angle relative to the surface normal. This indicates improved molecular packing compared with SAMs deposited in pure ethanol. Our analysis indicates that the SAM chemically binds to ITO primarily through PO3 2- groups in the presence of toluene, whereas -PO2OH- contributes when ethanol is used alone. The optimized SAM was shown to significantly enhance perovskite crystal growth, producing larger, more homogeneously distributed crystals (similar to 400 nm) compared to smaller, less ordered crystals grown on less optimized layers. These results highlight the critical role of SAM structure and deposition conditions in controlling perovskite film quality and provide insights for improving the performance of hybrid perovskite devices.

Carbon NanoCones (CNCs), distinguished by their conical shape and large surface area, are evaluated for their potential application in nerve gas [tabun (GA) and sarin (GB)] adsorption. Density Functional Theory (DFT) calculations, Molecular Dynamics (MD), and Monte Carlo (MC) simulations are employed to investigate this phenomenon comprehensively. The study findings indicate that tabun (GA) and sarin (GB) undergo spontaneous adsorption, characterized by significant negative energy values. Density Functional Theory (DFT) calculations indicate electron donation tendencies of nerve agents to CNC surfaces. Computational analysis shows higher adsorption efficiency in the inner portion (P1) of CNCs. Molecular Dynamics (MD) and Monte Carlo (MC) simulations confirm planar adsorption configurations parallel to CNC surfaces. The DFT calculations show that GA has a far greater adsorption energy on a Carbon Nanocone compared to GB (−44.96 kcal/mol for GA, whereas GB has an adsorption energy of −35.95 kcal/mol). Furthermore, the analysis reveals significant differences between Sarin and Tabun nerve agents. Sarin exhibits higher global hardness, indicating increased stability, while Tabun shows higher overall softness, suggesting greater reactivity. Despite similar electronegativities, Sarin’s greater ionization energy and electron affinity imply enhanced stability and reactivity. Differences in HOMO and LUMO energies highlight unique reactivity profiles, with Sarin being more susceptible to nucleophilic attacks and Tabun to electrophilic attack. Sarin’s larger energy gap between HOMO and LUMO orbitals signifies its superior stability under electronic disturbances.

Abstract The polyol synthesis of CoO nanoparticles (NPs) is typically conducted by dissolving and heating cobalt acetate tetrahydrate and water in diethylene glycol (DEG). This process yields aggregates of approximately 100 nm made of partially aligned primary crystals. However, the synthesis demands careful temperature control to allow the nucleation of CoO while simultaneously preventing reduction, caused by the activity of DEG. This restriction hinders the flexibility to freely adjust synthesis conditions, impeding the ability to obtain particles with varied morpho-structural properties, which, in turn, directly impact chemical and physical attributes. In this context, the growth of CoO NPs in polyol was studied focusing on the effect of the polyol chain length and the synthesis temperature at two different water/cations ratios. During this investigation, we found that longer polyol chains remove the previous limits of the method, allowing the tuning of aggregate size (20–150 nm), shape (spherical-octahedral), and crystalline length (8–35 nm). Regarding the characterization, our focus revolved around investigating the magnetic properties inherent in the synthesized products. From this point of view, two pivotal findings emerged. Firstly, we identified small quantities of a layered hydroxide ferromagnetic intermediate, which acted as interference in our measurements. This intermediate exhibited magnetic properties consistent with features observed in other publications on CoO produced in systems compatible with the intermediate formation. Optimal synthetic conditions that prevent the impurity from forming were found. This resolution clarifies several ambiguities existing in literature about CoO low-temperature magnetic behavior. Secondly, a regular relationship of the NPs' TN with their crystallite size was found, allowing us to regulate TN over ~ 80 K. For the first time, a branching was found in this structure-dependent magnetic feature, with samples of spheroidal morphology consistently having lower magnetic temperatures, when compared to samples with faceted/octahedral shape, providing compelling evidence for a novel physical parameter influencing the TN of a material. These two findings contribute to the understanding of the fundamental properties of CoO and antiferromagnetic materials.

Intrachain transport in molecular junctions (MJs) longer than 5 nm has been modeled within the theoretical framework of Marcus theory. We show that in oligo(bisthienylbenzene)-based MJs, electronic transport involves polarons, localized on three monomers that are close to 4 nm in length. They hop and tunnel between adjacent localized sites with reorganization energies lambda close to 400-600 meV and electronic coupling parameters H-ab close to lambda/2. As a consequence, the activation energy for intrachain transport, given by the equation Delta G* = (lambda/4)(1 - 2H(ab)/lambda)(2), is close to zero, and transport along the chain is activationless, in agreement with experimental observation. On the contrary, similar calculations on conjugated oligonaphthalenefluoreneimine wires show that H-ab is much less than lambda/2 and predict that the activation energies for intrachain hopping between adjacent sites, close to lambda/4, are similar to 115 meV. This work proposes a new perspective for understanding long-range activationless transport in MJs beyond the tunneling regime.

The current work investigated the interaction of ZnO nanoparticles (NPs) with glycine, tyrosine, methionine and phenylalanine. (ZnO)12 cage-like cluster was modeled using the density functional theory to determine the adsorption energy, the preferred sites for adsorption of amino acids, and the electronic structure of the formed complexes. The findings suggest that pure amino acids interact with (ZnO)12 via a chemisorption process. The thermodynamic parameters computed showed that the complexation is an exothermic process and enthalpy-driven. The oxygen atoms in the carboxyl groups of the four studied amino acids are involved in the adsorption process. PHE_Zn12O12 exhibits the highest adsorption energy (− 207.50 kJ/mol) due to its interaction with the Zn12O12 nanocluster through two different adsorption sites. The electronic and sensing properties were examined by analyzing the HOMO and LUMO energies and the HOMO–LUMO energy gap (|ΔEg|). The sensitivity of Zn12O12 nanocluster toward the studied amino acids was examined by comparing the percentage variation of the gap after the adsorption, which can reach the value of 38

Many efforts have been made recently to develop solutions to corrosion problems. The current study was focused on synthesizing a new epoxy compound called Tetraglycidyl orthophenyl diamine (TGOPDA) and using it as a powerful inhibitor of carbon steel C38 in 1 M HCl for the first time. Furthermore, the title molecule’s structure was discovered utilizing Fourier transform infrared spectroscopy. The corrosion inhibition and adsorption behavior of TGOPDA onto C38 surface was then evaluated in 1 M HCl utilizing the weight loss measurements, thermodynamic/kinetic parameters and electrochemical techniques (Open circuit potential), Potentiodynamic polarization (PDP) and Electrochemical impedance spectroscopy (EIS)). Additionally, surface morphology (SEM/EDX) with computational tools such as: DFT (Density functional theory) calculations, RDF (Radial distribution function) analysis, MC (Monte Carlo) and MD (Molecular dynamic) simulations were combined to get insights into our inhibitor adsorption on C38 steel surface. The EIS tests demonstrated that the addition of TGOPDA improved the effectiveness of C38 steel inhibition, reaching about 95.27

A density functional theory (DFT) investigation was performed to elucidate the interaction mechanisms between boric acid (BA) and various macrocyclic host molecules. The calculated complexation energies were negative, indicating that these interactions are energetically favorable. Structural analyses revealed the formation of hydrogen bonds, particularly between BA and the hosts β-cyclodextrin (β-CD), pillar[5]arene (P[5]), and pyrogallol[5]arene (P[5]G). Notably, the hydroxyl groups (OH) of BA played a crucial role in establishing intermolecular hydrogen bonds, which significantly enhanced the stability of the BA/β-CD and BA/P[5] complexes, as confirmed by natural bond orbital (NBO) and intermolecular Gradient model based on Hirshfeld partition (IGMH) analyses. Furthermore, the calculated HOMO–LUMO energy gaps for the BA/β-CD, BA/P[5], and BA/P[5]G complexes were found to be larger than those of the individual hosts, indicating a kinetically stable systems. The studied host systems demonstrate potential for enhancing the bioavailability of boric acid and reducing its toxicity through effective host–guest recognition.

Quantum interference (QI) is well recognised as a significant contributing factor to the magnitude of molecular conductance values in both single-molecule and large area junctions. Numerous structure-property relationship studies have shown that para-connected oligo(phenyleneethynylene) (OPE) based molecular wires exemplify the impact of constructive quantum interference (CQI), whilst destructive quantum interference (DQI) effects are responsible for the orders of magnitude lower conductance of analogous meta-contacted OPE derivatives, despite the somewhat shorter effective tunnelling distance. Since molecular conductance is related to the value of the transmission function, evaluated at the electrode Fermi energy, T(EF), which in turn is influenced by the presence and relative energy of (anti)resonances, it follows that the relative single-molecule conductance of para- and meta-contacted OPE-type molecules is tuned both by the anchor group and the nature of the electrode materials used in the construction of molecular junctions (gold|molecule|gold vs. gold|molecule|graphene). It is shown here that whilst amine-contacted junctions show little influence of the electrode material on molecular conductance due to the similar electrode-molecule coupling through this anchor group to both types of electrodes, the weaker coupling between thiomethyl and ethynyl anchors and the graphene substrate electrode results in a relative enhancement of the DQI effect. This work highlights an additional parameter space to explore QI effects and establishes a new working model based on the electrode materials and anchor groups in modulating QI effects beyond the chemical structure of the molecular backbone.

In this investigation, the potential use of native β-cyclodextrin (β-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD) as encapsulating agents for trichloroethylene (TCE) was assessed. Various quantum chemical parameters, including HOMO, LUMO, and HOMO–LUMO gap, were calculated. The docking process was examined by considering different initial configurations. The complexation energies were calculated at the molecular level using DFT/BLYP-D4 and PBEh-3c calculations to gain insight into TCE encapsulation within the β-CD and HP-β-CD cavities. We used the independent gradient model (IGM) and extended charge decomposition analysis (ECDA) approaches to examine non-covalent interactions and charge transfer within TCE@β-CD and TCE@HP-β-CD complexes. The calculated thermodynamic data and complexation energies exhibited negative values for both considered complexes, indicating a favorable complexation process. Weak Van der Waals intermolecular interactions were the main driving forces in stabilizing the formed complex. Additionally, Monte Carlo simulations were conducted for a better understanding of the inclusion process. Our results provide evidence for the use of β-CD and HP-β-CD as suitable macrocyclic hosts for complexing trichloroethylene.

The work presented in this paper describes the preparation and the electrochemical application of functionalized chitosan-entrapped carbon paste electrodes (CH/CPE) for lead ions (Pb2+) detection in industrial wastewater. The chitosan was first functionalized using TiO2 and CuO, which were both metal oxides that were obtained by extracting it from waste products derived from shrimp shells. The analytical performance of the as-prepared electrodes, CH/CPE, TiO2-CH/CPE, and NiO-CH/CPE, for the detection of lead (II) was examined using electrochemical impedance spectroscopy (EIS) technique in the 0.1 M KNO3 electrolyte solution. The effect of experimental conditions, including polarization potential, frequency, and pH, are optimized to maximize the sensitivity of the measurements. The developed impedimetric sensors provided a linear response over a concentration range of 10−6 to 10−4 M with a detection limit of 3.10−7 M based on S/N = 3. The DFT computational analysis demonstrated that chitosan biopolymer possesses the ability to adsorb Pb (II) ions that are present in wastewater. Chitosan and the derivatives of chitosan, have the potential to remove heavy metals from industrial effluent in a manner that is both economical and eco-friendly to the environment. Chitosan is a biopolymer that is abundantly renewable.

Due to their detrimental and carcinogenic effects, synthetic organic dyes pose significant environmental and health risks. Consequently, addressing the bioremediation of industrial wastewater containing these organic dyes has become an urgent environmental concern. The adsorption using low-cost and green materials is one of the best alternative techniques for the removal of dyes. This study aims to investigate the use of chitin to eliminate Congo red (CR), an anionic dye, from wastewater. The chitin was produced from shrimp shell in a quick and environmentally friendly manner by utilizing a co-solvent (glycerol/citric acid (GLC)). The resulting adsorbent was characterized through various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and FT-IR spectroscopy. The effectiveness of CR removal with chitin was studied with respect to contact time, adsorbent dose, initial pH, equilibrium isotherms, and kinetic and thermodynamic parameters. It was observed that variations in the dye concentration and pH significantly influenced the removal of CR with chitin. Under optimal operating conditions (pH = 7, contact time = 130 min, temperature = 50 °C), the adsorption capacity reached 29.69 ± 0.2 mg/g. The experimental data revealed that CR adsorption onto a chitin adsorbent is better represented by a Langmuir isotherm.

This work is a mechanistic study of the CO2 reaction with diamines under both dry and wet conditions. All protic α,ω-diamines R1H1N1-(CH2)n-N2H2R2, with n = 1-5 and R1 and R2 = H and/or CH3, were investigated. Depending on the nature of the diamine, the reaction was found to follow one of two concerted asynchronous reaction mechanisms with a zwitterion hidden intermediate. Both mechanisms involved two processes. The first process consisted of a nucleophilic attack of the nitrogen N1 of the first amine group on the carbon of CO2, accompanied by the transfer of a hydrogen atom H1 from N1 to the nitrogen N2 of the second amine group, leading to the formation of a carbamate zwitterion. The subsequent process corresponds to the transfer of a hydrogen atom H2 from the second amine group N2 to an oxygen atom of CO2, thus ending the reaction by the formation of carbamic acid. The structure of the zwitterion hidden intermediate was determined using the reactive internal reaction coordinates (RIRC), a reaction pathway visualization tool, consisting of a 3D representation of the potential energy versus the internuclear distances N2-H1 and N2-H2, which correspond to the bond being formed and the bond being broken, respectively. The life span of the transitory species, i.e., the zwitterion, was found to depend on the nature of the second amine group. For primary amines, the life span of the zwitterion was "short", whereas for secondary amines, it was "long". The corresponding mechanisms were termed the "early" and "late" asynchronous mechanism, respectively. Regardless of the mechanism, the activation barriers were found to decrease with the length of the carbon chain linking the two amine groups, with an asymptotic behavior from n = 4. Involvement of a water molecule generates a significant catalytic effect for diamines with short carbon chains (n < 4), whereas for longer chain diamines, water has a slightly adverse effect.