Electronegative Atoms Research Articles

Chemical Bond Overlap Descriptors From Multiconfiguration Wavefunctions.

The chemical bond is a fundamental concept in chemistry, and various models and descriptors have evolved since the advent of quantum mechanics. This study extends the overlap density and its topological descriptors (OP/TOP) to multiconfigurational wavefunctions. We discuss a comparative analysis of OP/TOP descriptors using CASSCF and DCD-CAS(2) wavefunctions for a diverse range of molecular systems, including X-O bonds in X-OH (XH, Li, Na, H2B, H3C, H2N, HO, F) and Li-X' (XF, Cl, and Br). Results show that OP/TOP aligns with bonding models like the quantum theory of atoms in molecules (QTAIM) and local vibrational modes theory, revealing insights such as overlap densities shifting towards the more electronegative atom in polar bonds. The Li-F dissociation profile using OP/TOP descriptors demonstrated sensitivity to ionic/neutral inversion during Li-F dissociation, highlighting their potential for elucidating complex bond phenomena and offering new avenues for understanding multiconfigurational chemical bond dynamics.

One-step fabrication of high energy storage polymer films with a wide bandgap and high melting temperature induced by the fluorine effect for high temperature capacitor applications with ultra-high efficiency.

The development of polymer dielectrics with both high energy density and low energy loss is a formidable challenge in the area of high-temperature dielectric energy storage. To address this challenge, a class of polymers (Parylene F) are designed by alternating fluorinated aromatic rings and vinyl groups in the polymer chain to confine the conjugating sequence and broaden the bandgap with the fluorine effect. The target films with desired thickness, ultra-high purity, and a wide bandgap are facilely fabricated by a one-step chemical vapor deposition (CVD) technique from monomers. The symmetric and bulky aromatic structures exhibit high crystalline performance and excellent stability at high temperature. The presence of strongly electronegative fluorine atoms effectively enhances bandgap and electron trapping capability, which effectively reduces the conduction loss as well as the possibility of breakdown at high temperatures. CVD technology avoids the post-processing film-forming process, ensuring the fabrication of thin films with high quality. These benefits allow Parylene F films to effectively store electrical energy at temperature up to 150 °C, exhibiting a record discharged energy density of 2.92 J cm-3 at charge-discharge efficiency exceeding 90%. This work provides a new idea for the design and synthesis of all-organic polymer dielectric films for high temperature applications.

Computational insights into photo-induced behaviours for chalcogen doping 2-benzooxazol-2-yl-5-diethylamino-phenol derivatives

In view of the distinguished photochemical and photobiological characteristics of 2-Benzooxazol-2-yl-5-diethylamino-phenol (BYDP) and its derivatives, herein, we mainly focus on probing into excited-state behaviours of the three chalcogen element substituted BYDP derivatives (i.e. BYDP-O, BYDP-S and BYDP-Se). For these three different fluorophores, we detangle the effects of atomic electronegativity and charge recombination related to oxygen elements in excited-state intramolecular proton-transfer (ESIPT) processes. Because of the low potential energy barriers, we confirm that the ESIPT is controlled by atomic electronegativity. We sincerely hope our work could provide a theoretical reference for proving this novel mechanism of ESIPT experimentally.

Heteroatom-Based Ligand Engineering of Metal Organic Frameworks for Efficient and Robust Electrochemical Water Oxidation.

Metal-organic frameworks (MOFs) are promising catalysts for the electrochemical oxygen evolution reaction (OER) due to their high surface area, tunable pore structures, and abundant active sites. Ligand engineering is an important strategy to optimize their performance. Here, we report the synthesis of NiFe-MOFs based on three different ligands: 1,4-terephthalic acid (BDC), 2,4-thiophene dicarboxylic acid (TDC), and 2,5-furandicarboxylic acid (FDC), to investigate the effects of heteroatom-based aromatic rings on OER performance. It is revealed that by incorporating electronegative sulfur and oxygen atoms into the ligands, the electron density at the metal sites is reduced, leading to enhanced metal-oxygen covalency and improved charge transfer kinetics. The NiFe-FDC/NF catalyst demonstrates an overpotential of 189 mV at 10 mA⋅cm-2 and stable performance over 1300 hours at 1 A cm-2. In situ infrared spectroscopy reveal minimal structural reconstruction in NiFe-FDC/NF, contributing to its superior stability. The NiFe-FDC/NF were then subjected to 3600 hours of OER operation and it's metal elution was monitored. These findings offer a novel approach to ligand design for high-performance MOF-based OER catalysts, highlighting the potential of furan-based ligands for MOF ligand engineering.

Insights through molecular modeling into the structural requirement of Phenyl(6-phenylpyrazin-2-yl)methanone derivatives as aldose reductase inhibitors

Aldose reductase, play an important role in the pathogenesis of diabetic complications such as neuropathy, nephropathy and retinopathy. Therefore design of aldose reductase inhibitors has received considerable attention. In the present study molecular insights were explored through docking and QSAR. The quantification of the structural features of Phenyl(6-phenylpyrazin-2-yl)methanone analogs inferred that atomic Senderson electronegativity, van der Waals volume and charge distribution on the molecule are decisive for the aldose reductase inhibitory activity. Moreover, docking study depicted that benzonoid system of scaffold is crucial for - interaction with the side chain of key aromatic amino acids i.e. TRP111 and TRP20. These structural insights might provide significant roadmap for continuing search of potential ARIs prior to synthesis.

B─C Bonding Configuration Manipulation Strategy Toward Synergistic Optimization of Polarization Loss and Conductive Loss for Highly Efficient Electromagnetic Wave Absorption

AbstractIn non‐metallic atom‐doped carbonaceous materials, the disparity in electronegativity between the doped constituents and carbon atoms predetermines the bonding topology of covalent bonds and the distribution of electron density. This, consequently, influences the polarization and electron transport behavior within the doped domain and the electromagnetic wave attenuation attributes of the carbonaceous material. However, the influence of covalent bonds formed by doping with weakly electronegative atoms on electron density distribution, polarization effects, and electromagnetic wave attenuation remains uncharted. To address this deficiency, this study fabricates a porous carbonaceous material (NCP) and incorporates boron‐doped atoms to form a material with tunable B─C bonding configurations (B‐NCP). By modulating the B─C bonding configuration and proportion, it is feasible to achieve the synergistic optimization of conductive loss and polarization loss of the B‐NCP specimen. The optimized prototype B‐NCP‐1200 sample displays exceptionally efficient electromagnetic wave absorption capabilities with a minimum reflection loss (RLmin) of −52.03 dB and an effective absorption bandwidth (EAB) of 5.36 GHz. This study presents a conscientious model for comprehending the electromagnetic attenuation mechanisms associated with weakly electronegative atom doping in carbon‐based electromagnetic wave‐absorbing materials.

Quantitative Structure Activity Relationship Analysis of Benzimidazole Derivatives as Aldose Reductase Inhibitors

Hyperglycemia is involved in the pathogenesis of diabetic neuropathy, retinopathy, nephropathy, and macro-vascular disease via multiple mechanisms, of which increased aldose reductase activity. Aldose reductase inhibitors, when administered from the onset of hyperglycemia, prevent the progression of polyol accumulation–linked complication. In this work, we report quantitative structure activity relationship analysis performed on the Triazino[4,3-α]benzimidazole acetic acid derivatives as aldose reductase inhibitors. The molecular modeling study was performed by using the software BioMed CAChe 6.0 and the regression analysis by SYSTAT 10.2. Various physicochemical parameters belonging to different classes viz. hydrophobic, steric and electronic etc. were calculated. QSAR models were generated using 17 compounds. The model showed a good correlative and predictive ability having convention coefficient (r2) of 0.846 and cross-validated correlation coefficient (q2) of 0.6866 by LOO external validation method. Based on the developed QSAR model, it may be concluded that aldose reductase inhibition activity of benzimidazole acetic acid derivatives is strongly influenced by the thermodynamic and electronic nature of the substituents. QSAR model shows that LOGP, LUMO energy, and steric energy are negatively affecting the biological activity. For a molecule to have higher aldose reductase activity, compound should be less lipophilic and should have more electronegative groups or atoms than electropositive groups or atoms present in the compound.

Tactfully regulating the ESIPT mechanism of novel benzazolyl-4-quinolones fluorophore by atomic electronegativity

The effects of atomic electronegativity (O, S and Se) on the excited state intramolecular proton transfer (ESIPT) behavior of fluorescent benzazolyl-4-quinolones derivatives have been investigated theoretically. Analysis of structure parameters and infrared vibrational spectra indicate that the intramolecular hydrogen bonds (O1H1⋯N1) are gradually strengthened in the first (S1) excited state as the atomic electronegativity diminishes (O → S → Se). The topological parameters, reduced density gradient (RDG) scatter plots and interaction region indicator (IRI) isosurface further confirm our results. The energy gap of molecular orbitals reflect that the less atomic electronegativity prompt greater excited state reactivity. In addition, the constructed potential energy curves (PECs) reveal that Se substituent has lower potential barrier (0.42 kcal/mol), which is more likely to accelerate the occurrence of ESIPT process. These results show that the atomic electronegativity helps to regulate the ESIPT process, which will pave the way for the design and synthesis of ESIPT-based fluorophores in future.

Computational detangling chalcogen elements substitutions associated ESDPT mechanism for oxazolinyl-substituted hydroxyfluorene derivatives

In view of the distinguished photochemical and photobiological characteristics of oxazolinyl-substituted hydroxyfluorene and its derivatives, herein, we mainly focus on probing into excited state behaviors of the novel 9,9-dimethyl-3,6-dihydroxy-2,7-bis(4,5-dihydro-4,4-dimethyl-2-oxazolyl) fluorene (Oxa-OH) derivatives. In light of the significant effects resulting from substituting oxygen elements, three Oxa-OH derivatives (i.e., Oxa-OO, Oxa-SS and Oxa-SeSe fluorophores) are considered in this work. For these three different fluorophores, we detangle the effects of atomic electronegativity and charge recombination related to oxygen elements in excited state double proton transfer (ESDPT) processes. Because of the low potential energy barriers, we confirm the ESDPT happens by the sequential type. Based on heterosubstituted Oxa-OS and Oxa-OSe compounds, we further verify the chalcogen atomic-electronegativity-regulated stepwise ESDPT mechanism. We sincerely wish our work could provide a theoretical reference for proving this novel mechanism of ESDPT experimentally.

Homoleptic and Heteroleptic Coordination Environment of Palladium Molecular Catalysts for Oxygen Reduction to Hydrogen Peroxide

Hydrogen peroxide (H2O2) serves a wide range of purposes in industries such as chemical manufacturing, energy production, and wastewater treatment, either alone or in combination with other oxidizers. The demand for H2O2 has seen a notable increase due to its heightened use in disinfection amid the COVID-19 pandemic. Currently, industrial synthesis of H2O2 relies on anthraquinone technology, a complex process involving multiple steps including the use of H2 gas, transfer of H2O2 between solvents, distillation of concentrated H2O2, and potentially hazardous transportation. Thus, advancements in developing efficient and selective electrocatalysts for the two-electron oxygen reduction reaction (2e- ORR) are crucial for promoting the adoption of electrochemical synthesis of H2O2 production. In our study, we synthesized single-atom electrocatalysts—Pd-N4-CO, Pd-S4-NCO, and Pd-N2O2-C through an in-situ synthesis approach involving heteroatom-rich ligands and activated carbon under mild reaction conditions. These catalysts feature both homoleptic (Pd-N, Pd-S) and heteroleptic (Pd-NO) coordination spheres, which are expected to demonstrate selectivity in the two-electron/four-electron pathway of the oxygen reduction rection (ORR). Moreover, the coordination of the Schiff base and poly pyridyl ligands to the palladium atom could be observed via the thiol ligand (Pd-S4-NCO), azomethine nitrogen and hydroxyl oxygen atoms (Pd-N2O2-C), and the pyridinic nitrogen atom of 1,10-phenathroline-5,6-dione (Pd-N4-CO). Notably, Pd-N4-CO shows promise as an electrocatalyst for two-electron ORR, facilitating green H2O2 production with high activity and selectivity in a basic electrolyte, exhibiting minimal onset overpotential and over 95% selectivity across various potentials. The electrocatalysts performance in ORR follows Pd-N4-CO > Pd-N2O2-C > Pd-S4-NCO, aligning with the Pull-Push mechanism. This mechanism underscores the significance of strong coordination of Pd with electronegative donor atoms like N and O, and weak coordination with intermediate *OOH, enhancing selectivity and green H2O2 production. Our findings, both experimental and DFT calculations, offer new insights into engineering heteroatom-rich ligands to tune the electronic structure of catalytic active sites. This understanding informs the atomic-level structure-activity and selectivity relationship, facilitating the development of more effective and efficient catalysts for the electrochemical synthesis of hydrogen peroxide.

Superconductivity of Electrodeposited Rhenium Alloys

Superconductivity of Electrodeposited Rhenium Alloys Rhenium (Re) is a type I superconductor with an intrinsic superconducting transition temperature, or the critical temperature (Tc), at 1.7 K. Electrodeposited Re has been found to be in its amorphous state with an enhanced critical temperature of 6 K[1]. This enhancement enables superconductivity beyond the boiling point of liquid helium, i.e. 4.2K, facilitating the applications of Re in the connectivity for quantum devices. In addition, Re also maintains its ductility without undergoing ductile-to-brittle transition as temperature decreases, owing to its hexagonal close-packed (hcp) crystal structure[2], which further supports its accessibility to cryogenic electronic application, such as interconnects in quantum devices. However, this enhancement in T directly results from the amorphous or nanocrystalline grain structure and rapidly degrades upon Re recrystallization at elevated temperatures.In order to improve the thermal stability of the T of nanocrystalline Re or even further increase the Tc, rhenium films doped with other elements have been electrodeposited. For example, while alloying Re with Fe inhibits the recrystallization, the superconductivity of ReFe is found significantly suppressed. On the other hand, while Co doping suppresses the superconductivity to a much less degree, it has no impact on the recrystallization. Between these two alloying elements, both Fe and Co are ferromagnetic and have similar atomic radius. Yet, they have completely different crystal structures and are also different with respect to the Re host.The present work continues from previous studies to perform systematic comparison between dopants with various atomic radius, electronegativity, magnetism, and intrinsic crystallographic configurations to identify the determining factor for alloy superconductivity and the thermal stability. For example, Figure 1 shows the XRD patterns of as-deposited ReRu alloy films with controlled Ru contents as well as the same films after thermal annealing at various elevated temperatures. The electrodeposition is carried out on rotating Cu disk electrodes. The concentration of Re and Ru in electrolyte and the time of deposition are varied in order to achieve different composition and to keep film thickness between 300 and 400 nm. Film composition and thickness are measured using x-ray fluorescence spectroscopy (XRF). The film grain structure and superconductivity as well as their thermal stability will be discussed in detail in the presentation. Reference Pappas, D.P., et al., Enhanced superconducting transition temperature in electroplated rhenium. Applied Physics Letters, 2018. 112(18).Naor, A., et al., Properties and applications of rhenium and its alloys. Ammtiac Quarterly, 2010. 5(11).Malekpouri, B., K. Ahammed, and Q. Huang, Electrodeposition and superconductivity of rhenium-iron alloy films from water-in-salt electrolytes. Journal of Alloys and Compounds, 2022. 912: p. 165077.De, S., et al., Electrodeposition of superconducting rhenium-cobalt alloys from water-in-salt electrolytes. Journal of Electroanalytical Chemistry, 2020. 860: p. 113889. Figure 1. XRD patterns of rhenium-ruthenium alloy films (a) before annealing, after annealing at (b) 150 °C, (c) 200 °C, (d) 300 °C. XRD standards of pure Re and Cu are included in (c) and (d). Figure 1

A theoretical exploration of the influence of oxygen element on photo-induced behaviours for flavonoid derivatives with Me2N substitution

The exceptional properties of flavonoid derivatives are a great inspiration for our research. In the fields of medicine and chemistry, flavonoids present the superior ability to enhance non-specific immune function and humoral immune response. Herein, our primary focus lies in the theoretical exploration of the photo-induced characteristics exhibited by the novel Me2N-substituted flavonoid (MEF) fluorophore. Considering the potential photo-induced properties associated with chalcogen atomic electronegativity in photoexcitation, using density functional theory (DFT) and time-dependent DFT (TDDFT) methods, we primarily pay attention to probing into photo-induced hydrogen bonding effects and concomitant charge reorganisation processes. Given changes in chemical geometries and the infrared (IR) vibrational shifts of three MEF derivatives (MEF-O, MEF-S and MEF-Se), we confirm that intramolecular hydrogen bonding should be strengthened by facilitating excited state intramolecular proton transfer (ESIPT) reactions. Particularly, the redistribution of charge further shows the ESIPT behaviour. By constructing potential energy curves (PECs) and identifying transitional reaction state (TS) structures, we ultimately validate the electronegativity-dependent ESIPT mechanisms of chalcogen elements in MEF derivatives. We sincerely hope that our work can accelerate future development and applications of flavonoid derivatives.

1,4-Bis(pyridin-1-ium)benzene trifluoroacetate coordinated to chloropropyl functionalized SiO2-nano-NiFe2O4 (BPBTCSF): As a novel and effectual mesoporous bi-functional magnetic catalyst for the synthesis pyrido[2,3-d:6,5-d']dipyrimidines

Here in, we report the synthesis of 1,4-Bis(pyridin-1-ium)benzene trifluoroacetate coordinated to chloropropyl functionalized SiO2-nano-NiFe2O4 (BPBTCSF). Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), elemental mapping analysis, Brunauer-Emmett-Teller (BET), thermal gravimetric analysis (TGA), vibrating-sample magnetometry (VSM) and X-ray diffraction (XRD) techniques characterized the framework of this catalyst. The catalytic activity of this nano-composite was then examined in the one-pot four-component reaction of 2-thiobarbituric acid, NH4OAc, and aldehyde for synthesis of pyrido[2,3-d:6,5-d']dipyrimidines under optimal conditions (5 mg of BPBTCSF, H2O, 25 °C). BPBTCSF exhibits benefits as a heterogeneous catalyst, such as exciting performance in the production of derivatives (2 to 5 min, 90 % to 98 %), six times reproducibility with a slight decrease in catalytic activity, the simultaneous presence of acidic and basic sites (Hydrogen attached to the electronegative nitrogen atom and CF3COOˉ, respectively), convenient purification and separation from the reaction mixture.

The molecular structure, electronic properties, and decomposition mechanism of FOX-7 under external electric field were calculated based on density functional theory.

Based on the density functional theory (DFT), we analyzed the changes of the FOX-7 molecule under external electric field (EEF) from multiple perspectives, including molecular structure, electronic structure, decomposition mechanism, frontier molecular orbitals (FMOs), and density of states (DOS). The results revealed that as the intensity of the positive EEF increased, the detonation performance of the FOX-7 molecule was significantly enhanced, while its thermal stability was also improved. This discovery challenges the traditional concept that explosives are inherently dangerous under external electric fields and provides new insights for research in related fields. To further explore the impact of EEF on the thermal stability of FOX-7, we conducted a thorough analysis of the mechanism by which EEF affects the decomposition process. Our findings indicate that applying a positive EEF significantly increases the energy required to overcome intramolecular hydrogen transfer and C-NO2 bond rupture, while having a relatively minor effect on the nitro isomerization process. This observation further demonstrates that the appropriate application of a positive EEF can enhance the detonation performance of FOX-7 without compromising its thermal stability. Further research revealed that as the intensity of the positive EEF increased, the electronegativity of the nitro group gradually enhanced, leading to an increase in the electronegativity of the oxygen atoms within it. This made the oxygen atoms more prone to participating in chemical reactions. This phenomenon also explains why the energy barrier required for nitro isomerization in FOX-7 gradually decreases as the intensity of the positive EEF increases. Based on the density functional theory (DFT), the structural optimizations were performed both under applied EEF and without EEF at the B3LYP/6-311G (d, p) level. All optimized results were converged and exhibited no imaginary frequencies. Based on the optimized structures, single-point energy calculations were further conducted at the B3LYP/def2-TZVPP level. Subsequently, analyses of molecular structure, electronic structure, decomposition mechanism, frontier molecular orbitals, and density of states were carried out.

Impact of molecular structure on the biological removal efficiency of fluoroquinolone antibiotics: An in-silico approach

Fluoroquinolone antibiotics (FQs), one of the most widely used antibacterials, have been recognized as emerging contaminants with adverse human health concerns. To overcome the adverse effects, a theoretical molecular design and screening approach was developed in this study to improve the removal efficiency of FQs by Chlorella in artificial or natural wetland systems. Among the 189 designed norfloxacin (NOR) derivatives, NOR-140 was screened with significantly improved biosorption, bioaccumulation, and biodegradation removal and functional effects, and reduced human health and ecological risks. The removal mechanism NOR-140 was also analyzed using adsorption kinetics, molecular docking, molecular dynamics simulations and machine learning models. Protein and polysaccharide structures play a major role in the adsorption process, polarizability and molecular volume of NOR-140 affect the bioaccumulation ability, and hydrogen bonding was found as the key force promoting the degradation ability of NOR-140. Modifying specific sites (5, 8, and 13) with functional groups containing highly electronegative atoms (O, F) significantly enhances the biodegradability of FQs alternatives by Chlorella. This study provided theoretical support for designing environmentally friendly FQs alternatives with improved degradation ability and advanced the understanding of how the FQs' molecular structures affect its removal by Chlorella.

DFT molecular modeling investigation and optical properties characterization of CR-39 films

Abstract In this study, the structural and optical characteristics of CR-39 films were investigated both theoretically and experimentally. A number of parameters for the CR-39 structure were theoretically computed by the density functional theory (DFT) method at B3LYP/6–311 G (p, d) level of theory. FTIR and UV/Vis spectroscopy were used to determine the structure compositions and the optical parameters of the CR39 film, respectively. The computed and experimental findings show good concordance. It was found that the CR-39 compound’s total energy, dipole moment, and energy difference between the LUMO and HOMO were, respectively, −994.575 a.u., 2.772 Debye, and 7.045 eV. The MEP showed a progressive change in color, with blue signifying a low electron density and red denoting a high electron density linked to nucleophilic reactivity and electrophilic reactivity. Further, the positive charges on all hydrogen atoms, which range from 0.16506 to 0.22032 a.u., imply that they are acceptors. The positive H34 is strongly produced when electrons from the negatively charged C17 are taken up. Because they are donor atoms, part of the carbon atoms in the structure is negative, while the other atoms are positive. The highest electronegative atoms H23 and H24 were substituted, resulting in the extremely negative carbon atom C7 (−0.32436). According to the experimentally determined absorption coefficient and energy gap values, CR-39 films may find application in optoelectronic devices.

Functionalized Quasi-Solid-State Electrolytes in Aqueous Zn-Ion Batteries for Flexible Devices: Challenges and Strategies.

The rapid development of wearable and intelligent flexible devices has posed strict requirements for power sources, including excellent mechanical strength, inherent safety, high energy density, and eco-friendliness. Zn-ion batteries with aqueous quasi-solid-state electrolytes (AQSSEs) with various functional groups that contain electronegative atoms (O/N/F) with tunable electron accumulation states are considered as a promising candidate to power the flexible devices and tremendous progress has been achieved in this prospering area. Herein, this review proposes a comprehensive summary of the recent achievements using the AQSSE in flexible devices by focusing on the significance of different functional groups. The fundamentals and challenges of the ZIBs are introduced from a chemical view in the first place. Then, the mechanism behind the stabilization of the flexible ZIBs with the functionalized AQSSE is summarized and explained in detail. Then the recent progress regarding the enhanced electrochemical stability of the ZIBs with the AQSSE is summarized and classified based on the functional groups on the polymer chain. The advanced characterization methods for the AQSSE are briefly introduced in the following sections. Last but not least, current challenges and future perspectives for this promising area are provided from the authors' point of view.

Understanding Cation-Anion Ionic Bonding in Tetramethylammonium Salts: Insights from Density Functional Theory and X-ray Crystallography.

In describing the charge on tetraalkylammonium ions, a charge of +1 is usually assigned. This is both the actual charge as well as the "formal charge" which is usually written on the nitrogen atom to indicate the electron deficiency experienced by the nitrogen atom relative to the valence electrons. Nitrogen is the most electronegative atom in the ion. The results in this study show that despite the convention of writing the positive charge on nitrogen, the ion is polarized through the σ bond framework to present four tetrahedral faces, each having close to a full charge of +1 to any anionic species which approach the cation.

Exploring the impact of Anions, Alkyl group and confinement effect in ionic liquid @ UiO-66(Zr) MOF: A DFT study

Metal organic frameworks (MOFs) have emerged as a strong research material due to their exceptional porosity and tunable functional nature. MOF structures consist of metal nodes with organic linker, which can be functionalized depending on the required application. With the tunable properties, it has wide range of applications in energy, environmental and therapeutic approaches. Nevertheless there are several factors which can affect their performance such as lower affinity towards target molecules, chemical and thermal stability etc. To counter these issues several studies have been devoted on functionalizing the MOF. In this work, we have considered UiO-66 (University of Oslo-66) MOF because of its exceptional thermal and chemical stability with a series of versatile ionic liquids (ILs). The selected ILs are 1-ethyl-3-methylimidazolium ([C2MIm]+) and 1‑butyl‑3-methylimidazolium ([C4MIm]+) cations with various anions [X]−, where X = acetate (OAc), tetrafluroborate (BF4), dicyanamide (DCA), nitrite (NO2) and chloride (Cl) anions. These ILs have been impregnated in tetrahedral (∼10 Å) and octahedral (∼16 Å) pores of UiO-66 structure. First principle density functional theory (DFT) approach is used to study the structure, stability, spectral properties and charge transfer between IL/UiO-66 interfaces. Our calculations suggest that, IL does not affect the structure of UiO-66 surface. The anion and the alkyl group in the cations play a vital role in the stability of the complexes. Furthermore, confinement effect influence the stability of the complexes, irrespective nature of anion and cation. Electron density and charge transfer analyses reveal that anions have profound liking towards MOF because of having high electronegative atoms. Our study will help to understand the molecular level interaction between IL@MOF interface, and these composite can be utilized for the energy and environment related applications.

Electronegativity Effects on Conformational Stability Using Bent's Rule: From Simple Molecules to Acetylcholine

Hybridization and electronegativity are fundamental concepts in chemistry connected by Bent's rule. This rule explains many aspects of the structural chemistry and reactivity of organic and inorganic compounds. Over decades, the application of Bent's rule has expanded, demonstrating its wide-ranging utility in elucidating molecular stability due to the substitution of highly electronegative atoms. This study successfully leverages Bent's rule to explain conformational energy difference in acetylcholine case using density-functional calculations. We used butane (Group 2) and butanone (Group 3) families to model the head of ACh+ and substituted one of the carbons with highly electronegative atoms: B, C, N, and O. This enabled us to evaluate the effects of electronegativity, as well as the presence of carbonyl groups, on their conformational stability and s character. There were three highlighted results. First, our calculations result in the s character are consistent with Bent's rule. Second, the high conformational energy differences can be attributed to the changes of s character in C2–Z bond: linear in Group 2 and exponential in Group 3, indicating the strong contribution of the carbonyl group. Third, the key determining factor in ACh+ conformational stability is the carbonyl group, which also strongly contributes to the solute-solvent interactions. Therefore, our study can be further applied to other similar molecules, potentially leading to broader applications in chemistry, especially for understanding ACh+ stability for Alzheimer’s Disease treatment.