High Electronegativity Research Articles

Physicochemical properties and cytochromes P-450 kinetics of the trifluoroacetamido derivative of phenacetin

Substituting hydrogen atoms with fluorine alters physicochemical properties often resulting in improved drug action relative to the parent molecule. The high electronegativity of fluorine changes the electron density distribution of the molecule; however, the substitution does not significantly change the size of the molecule because hydrogen and fluorine have similar atomic radii. A trifluoroacetamido derivative (TFA-phenacetin) of phenacetin, an analgesic antipyretic drug, was synthesized to compare its lipophilicity to the parent molecule by determining octanol–water partition coefficients. TFA-phenacetin is over seven times more lipophilic than phenacetin, which suggests that TFA-phenacetin would have better bioavailability relative to phenacetin. The kinetics of cytochromes P-450 (CYP) catalyzed oxidation of phenacetin and TFA-phenacetin were compared using Sprague Dawley (SD) rat liver microsomes. Phenacetin and TFA-phenacetin have the same apparent binding affinity for the SD rat liver microsome CYP proteome and undergo CYP catalyzed oxidation at the same rate in the presence of SD rat liver microsomes.

Natural Polyphenol‐Reinforced Ion‐Selective Separators for High‐Performance Lithium‐Sulfur Batteries with High Sulfur Loading and Lean Electrolyte

AbstractIon‐selective separators are promising to inhibit soluble intermediates shuttle in practical lithium‐sulfur (Li−S) batteries. However, designing and fabricating such high‐performance ion‐selective separators using cost‐effective, eco‐friendly, and versatile methods remains a formidable challenge. Here we present ion‐selective separators fabricated via the spontaneous deposition of green tea‐derived polyphenols onto a polypropylene separator, aimed at enhancing the stability of Li−S batteries. The resulting natural polyphenol‐reinforced ion‐selective (NPRIS24) separators exhibit rapid Li ion transport and high soluble intermediates inhibition capability with an ultralow shuttle rate of 0.67 % for Li2S4, 0.19 % for Li2S6 and 0.10 % for Li2S8. This superior ion‐selectivity arises from the high electronegativity and strong lithiophilic nature of the phenolic compounds. Consequently, we have achieved high‐performance Li−S batteries that are steadily cyclable under the challenging conditions of an S loading of 5.7 mg cm−2, an electrolyte‐to‐S ratio of 5.1 μL mg−1, and a 50 μm Li foil anode. Furthermore, the NPRIS24 separator enhances the performance of other Li metal batteries utilizing commercial LiFePO4 (5.3 mg cm−2) and LiNi0.5Co0.2Mn0.3O2 (9.9 mg cm−2) cathodes. This work underscores the potential of utilizing natural polyphenols for the design of advanced ion‐selective separators in energy storage systems.

Natural Polyphenol-Reinforced Ion-Selective Separators for High-Performance Lithium-Sulfur Batteries with High Sulfur Loading and Lean Electrolyte.

Ion-selective separators are promising to inhibit soluble intermediates shuttle in practical lithium-sulfur (Li-S) batteries. However, designing and fabricating such high-performance ion-selective separators using cost-effective, eco-friendly, and versatile methods remains a formidable challenge. Here we present ion-selective separators fabricated via the spontaneous deposition of green tea-derived polyphenols onto a polypropylene separator, aimed at enhancing the stability of Li-S batteries. The resulting natural polyphenol-reinforced ion-selective (NPRIS24) separators exhibit rapid Li ion transport and high soluble intermediates inhibition capability with an ultralow shuttle rate of 0.67 % for Li2S4, 0.19 % for Li2S6 and 0.10 % for Li2S8. This superior ion-selectivity arises from the high electronegativity and strong lithiophilic nature of the phenolic compounds. Consequently, we have achieved high-performance Li-S batteries that are steadily cyclable under the challenging conditions of an S loading of 5.7 mg cm-2, an electrolyte-to-S ratio of 5.1 μL mg-1, and a 50 μm Li foil anode. Furthermore, the NPRIS24 separator enhances the performance of other Li metal batteries utilizing commercial LiFePO4 (5.3 mg cm-2) and LiNi0.5Co0.2Mn0.3O2 (9.9 mg cm-2) cathodes. This work underscores the potential of utilizing natural polyphenols for the design of advanced ion-selective separators in energy storage systems.

Iron-Based Layered Perovskite Oxyfluoride Electrocatalyst for Oxygen Evolution: Insights from Crystal Facets with Heteroanionic Coordination.

Mixed-anion compounds have recently attracted attention as solid-state materials that exhibit properties unattainable with those of their single-anion counterparts. However, the use of mixed-anion compounds to control the morphology and engineer the crystal facets of electrocatalysts has been limited because their synthesis method is still immature. This study explored the electrocatalytic properties of a Pb-Fe oxyfluoride, Pb3Fe2O5F2, with a layered perovskite structure for oxygen evolution reaction (OER) and compared its properties in detail with those of a bulk-type cubic three-dimensional (3D) perovskite, PbFeO2F. A Pb3Fe2O5F2 electrode prepared with carbon nanotubes and a graphite sheet as a conductive support and a substrate, respectively, demonstrated better OER performance than a PbFeO2F electrode. The role of specific crystal facets of Pb3Fe2O5F2 in enhancing the OER activity was elucidated through electrochemical analysis. Density functional theory calculations indicated that the Pb3Fe2O5F2 (060) facet with Fe sites exhibited a lower theoretical overpotential for the OER, which was attributed to a moderately strong interaction between the active sites and the reaction intermediates; this interaction was reinforced by the strong electron-withdrawing behavior of fluoride ions. This finding offers new insights for developing efficient electrocatalysts based on oxyfluorides, leveraging the high electronegativity of fluorine to optimize the electronic states at active sites for the OER, without relying on precious metals.

Unraveling the promotive mechanism of nitrogen-doped porous carbon from wasted lignin for Cr (VI) removal

Persistent environmental pollution by heavy metals, particularly Cr (VI), poses significant risks to ecosystems and human health due to its high toxicity and bioaccumulation potential. The development of high-performance, cost-effective adsorbents from sustainable materials remains a critical challenge in the field of Cr (VI) remediation. This study investigates the influence of pyrrolic-N (N-5) within nitrogen-doped hierarchical porous carbon (N-HPC) on its adsorption capacity. Results indicate that N-HPC variants with a higher N-5 content exhibit superior adsorption abilities. The optimal sample demonstrated an exceptional adsorption capacity of 386.2 mg/g for Cr (VI). Even after seven regeneration cycles, this N-HPC variant maintained a remarkable 77.8 % removal efficiency for Cr (VI), highlighting its robust stability and selectivity. The relationship between the physicochemical properties of N-5 and N-HPC was thoroughly examined, revealing that N-5 plays a crucial role in the adsorption process. Due to its high electronegativity, nitrogen-doping into the carbon framework generates a dipole moment, enhancing the electronegativity of N-HPC, altering its local electron density and polarity, increasing specific surface area, carbon defect density, and ion exchange capacity. These factors collectively contribute to significant improvements in pore filling, ion exchange efficiency, and electrostatic adsorption by N-HPC. The reduction complexation mechanism emerges as the dominant factor in the adsorption process. N-5 not only provides reducing electrons as an electron donor, facilitating the continuous conversion of Cr (VI) to Cr (III), but also acts as an adsorption active site, complexing Cr to the surface of N-HPC. This synergistic effect strengthens the reduction complexation, enhances adsorption performance, and improves the regeneration cycle and adsorption selectivity for Cr.

Low-frequency contact-electro-catalysis driven by friction between the PTFE-coated fabric and dye solution

The phenomenon of contact electrification occurs when two materials with dissimilar work functions are in contact and charged. Contact-electro-catalysis may occur when electron exchange at the liquid-solid interface initiates a redox reaction. This type of catalysis, being classified as the category of mechanically-driven tribocatalysis, has been demonstrated to be able to degrade dye under high-frequency ultrasonic excitation, and is rarely realized under low-frequency friction driving. In this work, a high RhB dye decomposition ratio of 91.5 % is achieved by harnessing the ordinary low-frequency solid-liquid friction energy through the design and use of the recyclable fabric with PTFE coating as a solid friction source to agitate the dye solution. In the absence of PTFE coating, the RhB dye decomposition ratio is about 14.8 % under the same friction conditions. The enhanced contact-electro-catalysis may be attributed to the high electronegativity of PTFE coating. According to the quenching experiments with active species, it is found that both hydroxyl radical (·OH) and superoxide radical (·O2-) are these main active species induced by low-frequency solid-liquid friction. The fabric with PTFE coating after being dried and reused for 5 cycles still possesses 87.9 % RhB dye decomposition ratio. With these advantages of high decomposition ratio of organic pollution, low cost, good recyclability, and environmental friendliness, the developed low-frequency contact-electro-catalysis in this work, is potential for organic wastewater treatment application through utilizing waste solid materials to harvest the mechanical friction energy between solid waste fabrics and ordinary waterflow in future.

Synergistic N/F Dual-Doped MoC/C Catalyst Synthesized via Liquid Phase Plasma for Sustainable Ammonia Production.

NH3 is a versatile solution for the storage and distribution of sustainable energy, offering high energy density and promising applications as a renewable hydrogen carrier. However, electrochemical NH3 synthesis under ambient conditions remains challenging, such as low selectivity and efficiency, owing to the inertness of N≡N and competing reactions. In this study, a catalyst (MoC/NFC) comprising molybdenum carbide evenly dispersed on carbon doped with N and F heteroatoms was successfully synthesized using liquid-phase plasma. The MoC/NFC catalyst exhibited a maximum NH3 yield of 115 μg h-1 mg-1cat. with a faradaic efficiency of 1.15% at -0.7 V vs reversible hydrogen electrode in 0.1 M KOH electrolyte. Pyridinic- and pyrrolic-N atoms adjacent to the carbon pores served as active sites for N2 adsorption and enabled N2 triple bond cleavage. In addition, F doping contributed to N2 activation owing to the high electronegativity of 3.98, resulting in the attraction of more electrons. These findings demonstrate a significant advancement in the development of efficient catalysts for electrochemical ammonia synthesis, potentially paving the way for scalable and sustainable NH3 production methods that can support the growing demand for renewable energy storage solutions.

Metalloid Phosphorus Induces Tunable Defect Engineering in High Entropy Oxide Toward Advanced Lithium‐Ion Batteries

AbstractThe inferior electrical conductivity and sluggish lithium storage kinetics of conventional high‐entropy oxide (HEO) are critical issues hindering their commercialization. The high electronegativity of metalloids can ameliorate this predicament by altering the electronic configuration of HEO compared to metals. Herein, metalloid phosphorus doping in spinel‐type HEO (PxA1‐x)B2O4 (A/B = Cr, Mn, Fe, Co, Ni) (P‐HEO) is achieved through a facile sol–gel process. The metalloid phosphorus doping facilitates the transfer of electrons from transition metal sites to phosphorus‐doped sites, resulting in the formation of electron‐rich and electron‐deficient local regions on the HEO surface and is conducive to an increase in the total number of active lithium sites in the electrochemical reaction process. Density functional theory calculation reveals Li adsorption energy on the synthesized P‐HEO is only −1.102 eV, demonstrating that the phosphorus doping enables a strong electronic coupling between lithium ions and P‐HEO. Furthermore, metalloid phosphorus doping also leads to oxygen vacancies formation and lattice distortion, which significantly enhances charge transfer efficiency and diffusion kinetics and results in the enhanced lithium storage performance with impressive rate capability and long‐term stability. These findings provide valuable insights for the design of lattice‐engineered HEO as versatile electrodes for future energy storage applications.

Identification of novel Influenza virus H3N2 nucleoprotein inhibitors using most promising synthetic Epicatechin derivatives

Influenza A virus is a leading cause of acute respiratory tract infections, posing a significant global health threat and resulting in substantial annual financial losses due to seasonal epidemics. Current treatment options are limited and increasingly ineffective due to viral mutations. This study aimed to identify potential drug candidates targeting the nucleoprotein of the H3N2 subtype of Influenza A virus. We focused on epicatechin derivatives and employed a suite of cheminformatics approaches, including ADMET profiling, drug-likeness evaluation, PASS predictions, molecular docking, molecular dynamics simulations, Principal Component Analysis (PCA), dynamic cross-correlation matrix (DCCM) analyses, and free energy landscape assessments. Molecular docking and dynamics simulations revealed strong and stable binding interactions between the derivatives and the target protein, with complexes 01 and 81 exhibiting the highest binding affinities. Additionally, ADMET profiling indicated favorable pharmacokinetic properties for these compounds, supporting their potential as effective antiviral agents. Compound 81 demonstrated exceptional quantum chemical descriptors, including a small HOMO-LUMO energy gap, high electronegativity, and significant softness, suggesting high chemical reactivity and strong electron-accepting capabilities. These properties enhance Compound 81’s potential to interact effectively with the H3N2 nucleoprotein. Experimental validation is strongly recommended to advance these compounds toward the development of novel antiviral therapies to address the global threat of influenza.

Transition metal-modified armchair graphene network for high-performance hydrogen evolution reaction catalysts

This study explores the structural, electronic, and catalytic properties of armchair hexagonal graphene networks (AHGN) modified with single transition metal (TM) atoms from Period V. Substitutions of Ag, Mo, Nb, Pd, Rh, Ru, Tc, Y, and Zr were investigated, revealing significant changes in bond lengths, bond angles, and dihedral angles. The binding energies indicate that TM substitutions do not drastically destabilize AHGN, suggesting potential applications requiring modified electronic properties. Electronic investigations showed that TM substitutions influence the partial density of states (PDOS) and energy gaps (ΔE), with Tc significantly reducing ΔE, indicating a shift towards metallic behavior. Mulliken charge analysis highlighted the electron density redistribution around TM atoms and edge carbons, enhancing electronic conductivity and chemical reactivity. Based on the results, AHGN-Rh-H, AHGN-Pd-H, and AHGN-Mo-H demonstrate the most efficient catalytic performance for the hydrogen evolution reaction (HER), with ΔG values comparable to platinum, underscoring their potential for practical hydrogen production applications. Conversely, materials like AHGN-Nb-H and AHGN-Zr-H exhibit higher ΔG values, indicating lower efficiency for HER. Global reactivity parameters (GRPs) analysis revealed AHGN-Tc with the most negative chemical potential (−4.010 eV) and highest electronegativity (4.010 eV), indicating strong electron-accepting and electron-attracting abilities. These findings underscore the potential of TM-substituted AHGN for advanced electronic applications and efficient hydrogen production.

Enhanced Antibacterial Efficacy of Ag(I), Cu(II), and Zn(II) Modified Sodalite Zeolite Against Escherichia coli and Staphylococcus aureus

Sodalite zeolite modified with metal ions Ag+, Cu2+, Cu2+, and Zn2+ was successfully synthesized and evaluated for antibacterial activity. The research aims to obtain silver, copper, and zinc metal-modified sodalite separately and determine their antibacterial activity on Escherichia coli and Staphylococcus aureus bacteria. Sodalite zeolite was synthesized using ludox and sodium aluminate through hydrothermal methods, ensuring uniform crystal growth and optimal crystallinity, as confirmed by X-ray diffraction (XRD) analysis. The average particle sizes of the modified zeolites were determined to be 54.9 nm for Ag-Zeolite, 37.2 nm for Cu-Zeolite, and 28.56 nm for Zn-Zeolite, with structural changes observed through alterations in peak intensity. Scanning Electron Microscopy - Energy Dispersive X-ray (SEM-EDX) analysis showed no significant change in the zeolite’s morphology. In addition, the EDX results showed the presence of Ag (3.15%), Cu (3%), and Zn (2.41%) metals indicating successful ion exchange. Antibacterial assays revealed that Cu-Zeolite demonstrated superior efficacy inhibition zones against Escherichia coli (14.04±1.26) and Staphylococcus aureus (20.74±0.48), highlighting its potential as an antimicrobial agent. The mechanism of action involved the controlled release of metal ions, disrupting bacterial cell membranes and metabolic processes. Notably, Cu2+ ions exhibited the strongest antibacterial properties due to their smaller ionic radius and higher electronegativity than Ag+ and Zn2+. This research underscores the promising applications of metal-ion-modified sodalite zeolite in medical and environmental contexts.

Inhibiting Ion Migration and Stabilizing Crystal‐Phase in Halide Perovskite via Directly Incorporated Fluoride Anion

AbstractFluoride anion (F−) with extremely high electronegativity has been under intensive investigation in perovskite solar cells due to its remarkable defect suppression and great improvement of device performance. Nevertheless, these researches only focus on the surface, grain boundaries, or interface modification, the direct insertion of F− into the crystal lattice of regular lead halide perovskite films is still unrevealed. Herein, F− was successfully incorporated into the perovskite lattice by overcoming the insolubility of PbF2 via the introduced pyridinium halide as a novel volatile solubilizing ligand. The strong electronegativity of F− can strongly increase the binding energy of all the ions in CsPbI2Br and inhibit their defect formations. A trace amount of F− incorporation not only enhanced the optoelectronic properties but also effectively mitigated the ion migration and phase separation simultaneously. The photovoltaic performance and operational stability of perovskite solar cells were significantly improved with a champion efficiency of 17.78 % (38.01 %) under AM 1.5G (1000 lux indoor light). Moreover, F− can also be directly inserted into the hybrid perovskite lattice and greatly stabilized crystal‐phase, enabling efficient fully MA‐free FAPbI3 devices with 25.10 % efficiency. Our strategy sheds light on F‐containing perovskites and provides a promising way to tackle ion migration and stabilize the crystal phase in halide perovskites.

IPr*F - Highly Hindered, Fluorinated N-Heterocyclic Carbenes.

The introduction of fluorine atom has attracted considerable interest in molecular design owing to the high electronegativity and the resulting polarization of carbon-fluorine bonds. Simultaneously, sterically-hindered N-heterocyclic carbenes (NHCs) have received major interest due to high stabilization of the reactive metal centers, which has paved the way for the synthesis of stable and reactive organometallic compounds with broad applications in main group chemistry, inorganic synthesis and transition-metal-catalysis. Herein, we report the first class of sterically-hindered, fluorinated N-heterocyclic carbenes. These ligands feature variable fluorine substitution at the N-aromatic wingtip, permitting to rationally vary steric and electronic characteristics of the carbene center imparted by the fluorine atom. An efficient, one-pot synthesis of fluorinated IPr*F ligands is presented, enabling broad access of academic and industrial researchers to the fluorinated ligands. The evaluation of steric, electron-donating and π-accepting properties as well as coordination chemistry to Au(I), Rh(I) and Se is presented. Considering the unique properties of carbon-fluorine bonds, we anticipate that this novel class of fluorinated carbene ligands will find widespread application in stabilizing reactive metal centers.

Controllable Regulation of CO2 Adsorption Behavior via Precise Charge Donation Modulation for Highly Selective CO2 Electroreduction to Formic Acid.

The synthesis of value-added products via CO2 electroreduction (CO2ER) is of great significance, but the development of efficient and versatile strategies for the controllable selectivity tuning is extremely challenging. Herein, the tuning of CO2ER selectivity through the modulation of CO2 adsorption behavior is proposed. Using the constructed zeolitic MOF (SNNU-339), CO2 adsorption behavior is controllably changed from *CO2 to CO2* via the precise ligand-to-metal charge donation (LTMCD) regulation. It is confirmed that the high electronegativity of the coordinate ligand directly restricts the LTMCD, reduces the charge density on the metal sites, lowers the Gibbs free energy for CO2* adsorption, and leads to the transformation of CO2 adsorption mode from *CO2 to CO2*. Owing to the modulated CO2 adsorption behavior and regulated kinetics, SNNU-339 exhibits superior HCOOH selectivity (≈330% promotion, 85.6% Faradaic efficiency) and high CO2ER activity. The wide applicability of the proposed approach sheds light on the efficient CO2ER. This study provides a competitive strategy for rational catalyst design and underscores the significance of adsorption behavior tuning in electrocatalysis.

Stimulating the electrostatic interactions in composite cathodes using a slurry-fabricable polar binder for practical all-solid-state batteries

In this work, poly vinylidene fluoride–chlorotrifluoroethylene (PVdF-CTFE) is introduced as a slurry-fabricable polymer binder to fabricate a stable composite cathode using the complex materials of a Li[Ni0.7Co0.1Mn0.2]O2 cathode, Li6PS5Cl electrolyte, and super C carbon, for sulfide-based all-solid-state batteries (ASSBs). The high electronegativity of fluorine in the poly(vinylidene fluoride–chlorotrifluoroethylene (PVdF-CTFE) binder creates a polarized electronic environment in the composite cathode, promoting electrostatic interactions with Li ions. Compared with that of butadiene rubber (BR), the PVdF-CTFE binder has a stronger binding energy to the complex materials in the composite cathode, which enhances the mechanical rigidity of the composite cathode with highly uniform adhesion. In addition, uniform and close contact between the complex materials in the composite cathode reduces the resistance at the interfaces, lowering the energy barrier for Li+ diffusion, and eventually creates a fast Li+ diffusion pathway in the composite cathode. Thus, the pouch-type ASSBs cell, which comprises the composite cathode with the PVdF-CTFE binder, Li6PS5Cl electrolyte sheet, and silver-carbon (Ag/C) anodeless electrode delivers a high reversible capacity of 198.5 mAh g–1 at 0.1 C and long-term cycling stability over 300 cycles with a capacity retention of 74.5 % at 0.5 C at 60 °C.

Divergent Synthesis of Trifluoromethyl Ketones via Photoredox Activation of Halotrifluoroacetones

AbstractFluorine's high electronegativity, lipophilicity, and metabolic stability make it a valuable element for drug design and development. Consequently, significant synthetic efforts have focused on introducing fluorine and fluorinated motifs into organic molecules, with the synthesis of trifluoromethyl ketones (TFMKs) recently attracting considerable attention. Building on our ongoing research on radical organofluorine chemistry, we present herein the divergent synthesis of trifluoromethyl ketones directly from olefins using readily available chloro‐ and bromotrifluoroacetone as synthetic precursors of the trifluoroacetonyl radical under photoredox catalysis. Mechanistic studies revealed that the divergence is attained through radical polar crossover (RPC) and hydrogen atom transfer (HAT) mechanisms.

Enhancing heavy metals removal from water by thiol-incorporation of UiO-66 based metal organic framework nanosheets with l-cysteine

A new adsorbent, Cys-2D-UiO-66, was developed and applied to effectively eliminate heavy metal ions from water. The synthesis of 2D-UiO-66 involved developing a two-dimensional structure of UiO-66, created through an alkaline reaction medium, deviating from the normal three-dimensional structure. The advantage of 2D-UiO-66 nanosheet with a high aspect surface-to-thickness ratio is its ability to easily expose active sites on their surface to contaminants in solution, without diffusion limitations. Further attempts were made to enhance the adsorption capacity of the 2D-UiO-66 adsorbent by attaching l-cysteine to its surfaces through a simple one-pot process. This resulted in the modified adsorbent, Cys-2D-UiO-66, which exhibited exceptional adsorption performance. The adsorption experiments revealed that using Cys-2D-UiO-66 significantly improved the adsorption of Hg2+, Pb2+, and Cd2+ compared to 3D-UiO-66 (i.e. a 52 % increase for Hg2+, a 9.5-fold increase for Pb2+, and a 20-fold increase in Cd2+ adsorption). The adsorption equilibria of Cys-2D-UiO-66 align more closely with the Langmuir model, indicating that monolayer chemisorption mainly dominates the adsorption behavior. The thermodynamic study demonstrated that the adsorption of heavy metals onto the Cys-2D-UiO-66 favors higher temperatures. This fact is supported by thermodynamic calculations showing exothermic, favorable, and spontaneous chemisorption. The Cys-2D-UiO-66 adsorbent exhibited exceptional reusability with a marginal (less than 4 %) drop in adsorption performance after five successive cycles. Multicomponent adsorption results indicated a decline in the amount of adsorption for all species compared to the single component state due to competitive adsorption. FTIR analysis indicated that S–H and N–H groups aid in heavy metal ion adsorption, with Hg2+ ions being more easily adsorbed than Pb2+ and Cd2+ ions due to their higher electronegativity and ability to form covalent bonds with sulfur.

Constructing electrochemically stable single crystal Ni-rich cathode material via modification with high valence metal oxides

Single crystal Ni-rich cathode materials (SCNCM) are a good supplement in the market of nickel-based materials due to their safety and excellent electrochemical performance. However, the challenges of cation mixing, phase change during charge/discharge, and low thermal stability remain unresolved in single crystal particles. To address these issues, SCNCM are rationally modified by incorporating transition metal (TM) oxides, and the influence of metal ions with different valence states on the electrochemical properties of SCNCM is methodically explored through experimental results and theoretical calculations. Enhanced structural stability is demonstrated in SCNCM after the modifications, and the degree of improvement in the matrix materials varies depending on the valence state of doped TM ions. The highest structural stability is found in WO3-modified SCNCM, due to the smaller effective ion radii, higher electro-negativity, stronger W–O bond, and efficient suppression of oxygen vacancy generation. As a result, WO3-modified SCNCM have outstanding cycle performance, with a capacity retention rate of 90.2% after 200 cycles. This study provides an insight into the design of advanced SCNCM with enhanced reversibility and cyclability.

FK4H4-: Planar Tetracoordinate Fluorine Stabilized by Multicenter Ionic Bonding.

Planar tetracoordinate fluorine (ptF) species are very exotic and scarce due to high electronegativity of fluorine. Herein we report the ternary square ptF cluster, D4h FK4H4-, which is composed of a F center, a square K4 ring, and four outer H bridges. It is a true global minimum (GM) structure and possesses good dynamic stability. Bonding analyses indicate that there are four lone pairs for the central F atom, along with four K-H-K three-center two-electron (3c-2e) σ bonds for the peripheral K4H4 ligand ring. The stability of ptF is dominated by multicenter ionic bonds rather than the supposed σ aromaticity of the system. Excitingly, it is a pseudohalogen anion with the VDE 3.57 eV at the CCSD(T) level. The merge of ptF with pseudohalogen anion character makes the FK4H4- cluster an exotic species, which will motivate theoretical and experimental studies on novel ptF species as well as superhalogens.

Computational study of transition metal coordinated polyaniline: A first principle investigation into tuning the electronic properties of the resulting hybrid material

Tuning the electronic properties of polyaniline remains one of the most important features for the development of advanced materials in electronics. In this contribution, we use density functional theory to investigate the electronic properties of polyaniline when coordinating transition metals (Mn, Fe, Co, Cu, Zn) are embedded in the polymer structure.Importantly, the results reveal that in the presence of transition metal with high electronegativity, the coordinated polyaniline winds up with a decreased gap. Indeed, the band gap for H-PANI decreases from 0.911 eV to 0.513 eV for H-PANI-Mn (lower electronegativity) and to 0.201 eV for H-PANI-Zn (higher electronegativity). This reduction in the energy gap is attributed to enhanced electron delocalization due to increased overlap of electron wavefunctions in the hybrid structure. The results also reveal that the presence of transition metals lead to lower the chemical hardness from 3.252 eV in the case of H-PANI into 0.256 eV for H-PANI-Mn and 0.100 eV for H-PANI-Zn. Additionally, the results from molecular electrostatic potential highlight that PANI-Transition metal sustains more delocalization of charge density distribution compared to H-PANI, leading to molecule polarization which does play a crucial role in various chemical phenomena. These later reveal that the electron density polarization in polyaniline can interestingly be controlled through doping and coordinating the polymer structure with additional transition metals. Therefore, the obtained results might be used in the optimization of electrochemical charge storage in supercapacitors.