Redistribution Of Electron Density Research Articles

Potential risk resulting from the influence of static magnetic field upon living organisms. Numerically-simulated effects of the static magnetic field upon carbohydrates

Background: Recognising effects of static magnetic field (SMF) of varying flux density on flora and fauna is attempted. For this purpose, the influence of SMF upon molecules ofα- andβ-D-glucose,α- andβ-D-galactose,α- andβ-fructopyranoses,α- andβ-fructofuranoses andα- andβ-D-xylofuranoses andαandβ-D-xylopyranoses is studied.Methods: Computations of the effect of static magnetic field (SMF) of 0.0, 0.1, 1, 10 and 100 AFU (1 AFU > 1000 T) flux density were performed in silico for SMF changes distribution of the electron density in these molecules.Hyper-Chem 8.0 software was used together with the AM1 method for optimisation of the conformation of the molecules of monosaccharides under study. Then polarisability, charge distribution, potential and dipole moment for molecules placed in SMF were calculated involving DFT 3-21G method.Results: Application of SMF induced polarisability of electrons, atoms and dipoles, the latter resulting in eventual re-orientation of the molecules along the applied field of the molecules and the electron density redistribution at particular atoms. Increase in the field strength generated mostly irregular changes of the electron densities at particular atoms of the molecules as well as polarisabilities. Energy of these molecules and their dipole moments also varied with the SMF flux density applied.Conclusions: Saccharides present in the living organisms may participate in the response of the living organisms to SMF affecting metabolism of the molecules in the body fluids by fitting molecules to the enzymes. Structural changes of saccharide components of the cell membranes can influence the membrane permeability.

Lattice-strain engineering of CoOOH induced by NiMn-MOF for high-efficiency supercapacitor and water oxidation electrocatalysis

Lattice strain engineering is desirable to accelerate the electrochemical reaction kinetics but still lacks exploration. Here, we have endowed NiMn-MOF@CoOOH with multiple strains, which were introduced by NiMn-MOF. In such hybrid material, the NiMn-MOF not only stabilizes the structure to prevent the material from breaking during the electro-oxidation phase change process but also serves as an anchor point to tightly connect Co ions. The surface of CoOOH undergoes lattice stretching and compression and builds abundant vacancies and dislocations. The multiple lattice strains enable accelerated ion conduction through tensile/compressive strain and introduce additional electrochemically active sites. Regional vacancies and dislocation can change the stoichiometric ratio of some regions, leading to local electric field distortion and electron density redistribution. Moreover, the stacked network structure of the double-layer sheet provides more electrochemical active interfaces for electrochemical reactions, which greatly reduces the ion transport distance and promotes the rapid diffusion of electrolyte ions. The as-obtained NiMn-MOF@CoOOH demonstrates a superb capacity of 1771.4 at 1 A g−1 in supercapacitors. Meanwhile, when facing the water oxidation electrocatalysis reaction, it delivers low overpotentials of 221 mV at 10 mA cm−2 in an alkaline electrolyte. This report provides a novel strategy for lattice strain engineering on advanced materials for sustainable applications.

Single-Atom Mo Anchored on a Poly(heptazine imide) Nanosheet as a Novel Electrocatalyst Showing Excellent Behavior toward Nitrogen Reduction Reaction

Converting nitrogen into ammonia relying on the electrochemical nitrogen reduction reaction (NRR) is of great significance for sustaining life, and the development and screening of efficient electrocatalysts increasingly represent a major chemistry challenge. Herein, from density functional theory simulations, a series of recently developed poly(heptazine imide) (PHI)-anchored single-atom catalysts were investigated as the potential electrocatalysts for NRR, based on thermodynamics and kinetics analysis. The results reveal that the Mo-PHI nanosheet can effectively activate the inert N2 and promote N2 reduction to NH3 via the distal mechanism, which shows much better electrocatalytic activity than those of most ever-reported single-atom electrocatalysts, as reflected by the significantly much lower overpotential (0.05 V) and activation barrier (1.15 eV). The extraordinary activity of the Mo-PHI single layer is closely related to the efficient redistribution of electron density upon the adsorption of N2 molecules, which can promote the electron transfer from the substrate to the electron acceptors, N2. Moreover, the down-shift of projected density of states and the appropriately large d-band center (εd) of the central Mo metal is beneficial to the N2 adsorption for further reduction to generate NH3. Our predictions hence suggest the as-designed Mo-PHI single layer as a superior promising catalyst for efficient dinitrogen fixation and reduction.

Nanoscale Double-Heterojunctional Electrocatalyst for Hydrogen Evolution.

The active sites and charge/mass transfer properties in electrocatalysts play vital roles in kinetics and thermodynamics of electrocatalysis, and impose direct impacts on electrocatalytic performance, which cannot be achieved by a simplex structure. As a prototype, the authors propose a double‐heterojunctional nanostructure of NiS2/Ni3C@C containing NiS2/Ni3C and Ni3C/C heterojunctions as a general model to optimize the above issues and boost electrocatalytic performance. During the thermal reorganization, the in situ reaction between NiS2 nanoparticles and carbon induces the formation of Ni3C between them and constructs tightly contacted two kinds of interfaces among the three components. The TEM and XPS reveal the intimately contacted three components and the as‐constructed interacted dual interfaces, further confirming the formation of a porous double‐heterojunctional nanostructure. Theoretical calculations uncover that the electron density redistribution occurs at Ni3C/C interface by spontaneous electron transfer from defected carbon to Ni3C and lower ΔGH* achieves at NiS2/Ni3C interface by the concentrated interfacial charge density, which favors the simultaneous realization of high catalytic activity and rapid charge/mass transfer. When applied for hydrogen evolution reaction (HER), the porous double‐heterojunctional NiS2/Ni3C@C exhibits excellent HER activity and durability among all pH values. Profoundly, this special double‐heterojunctional structure can provide a new model for high‐performance electrocatalysts and beyond.

MODELING OF MELATONIN ANTIOXIDANT ACTIVITY IN ASPECT OF CLINICAL APPLICATION IN COVID-19

The most important function of melatonin according to medical clinical trials is antioxidant activity (along with gerontoprotective, anti-stress, immunomodulatory, anti-inflammatory, etc.), which is found everywhere in the human body, as melatonin penetrates all organs and tissues. Therefore, it is important to study the effectiveness of endogenous antioxidants by modelling the mechanism of their interaction with free radicals by quantum chemistry in combination with experimental methods, including electrochemical that enables not only to justify the positive effect of antioxidants, but also to establish the potential significance of these substances as medicines. Electrochemical studies have confirmed the antioxidant properties of melatonin and at the macroscopic level the fundamental difference in the mechanisms of inhibition of antioxidant molecules of hydroxyl radicals and superoxide anion radicals under predominant antioxidant activity with melatonin has been proven. The antioxidant activity of melatonin in the aspect of its clinical application in COVID-19 was supported by comparing the results of quantum chemical studies obtained at the nano-scale (redistribution of electron density, orders of relations between atoms, energy characteristics) with changes in the macroscopic parameters of the process of electroreduction of reactive oxygen species in the presence of melatonin. The potential of applying quantum chemical calculations in combination with electrochemical studies has been demonstrated to substantiate and establish the characteristics and differences of antioxidant activity of melatonin when interacting with a superoxide anion radical and a hydroxyl radical in order to predict ways to create new medicines based on the pharmacological activity of melatonin for its clinical use in COVID-19.

High-entropy alloy stabilized active Ir for highly efficient acidic oxygen evolution

We proposed a conceptual and experimental breakthrough in serving the nanoscale high-entropy alloy as substrates to stabilize the active Ir with ultra-low loading by using Fe, Co, Ni and Ru as stabilizing structural elements, achieving efficient and acid-stable OER performance. • HEA were used as substrates to stabilize the active Ir with ultra-low loading. • Ultra-small FeCoNiIrRu HEA NPs were in situ synthesized in CNFs. • FeCoNiIrRu HEA NPs exhibited thermodynamic induced phase evolution. • FeCoNiIrRu/CNFs exhibit low overpotential of 241 mV (10 mA cm −2 ). • OER performances were optimized by changing the metal compositions and calcination temperatures. We reported a conceptual and experimental breakthrough in serving the nanoscale high-entropy alloy (HEA) as substrates to stabilize the active Ir with ultra-low loading by using Fe, Co, Ni and Ru as stabilizing structural elements. The ultra-small FeCoNiIrRu HEA nanoparticles were in situ synthesized in electrospun carbon nanofibers (CNFs), and it exhibited thermodynamic induced phase evolution, as revealed by in situ characterization. The FeCoNiIrRu/CNFs exhibit exciting oxygen evolution reaction (OER) activity with low overpotential of 241 mV at 10 mA cm −2 and high mass activity of 205 mA mg -1 Ir+Ru . The hysteretic diffusion effect of HEA strongly inhibits the metal leaching and dissolution, leading to the excellent durability. The OER performance can be optimized by changing the metal compositions and calcination temperatures. In situ Raman spectra reveal the formation of OH and superoxo (OO) intermediates on HEA NP surfaces. Theoretically calculation indicate that the electron density redistribution in FeCoNiIrRu NPs occurs from low electronegative elements (Fe, Co, and Ni) to high electronegative ones (Ir, Ru) and it make the Ir more active to simultaneously promote the conversion of *OOH and generation of O 2 .

Solvent dependence of ESIPT process in 2-(2-carbonmethoxy-3,4-dichloro-6-hydroxyphenyl) compounds

After the synthesis of 2-(2-carbonmethoxy-3, 4-dichloro-6-hydroxyphenyl) (Compound 1), Elena V. Vetrova et al. found that it has different photophysical phenomena in the different solvent environment [Dyes and Pigments 180 (2020) 108417]. However, there is still no detailed theoretical research for this phenomenon. Therefore, based on the density functional (DFT) and time-dependent density functional (TD-DFT) methods, under different solvent conditions, the excited state intramolecular proton transfer process (ESIPT) of Compound 1 is investigated in this work. For Compound 1, the bond parameter analysis of the optimized structure confirms that the excited state hydrogen bond interaction is enhanced. The photophysical properties show that the theoretically simulated vertical transition energy is in good agreement with the experimental spectral value. Based on the optimized geometric structure, the frontier molecular orbital isosurface is drawn, and the redistribution of electron density in different solvents is depicted, which intuitively explain the changes in the photophysical properties of Compound 1. Though the calculated potential energy curves, we further explain that ESIPT process are easier to occur from Heptane, Dioxane, Toluene to THF.

Fluctuation of Interfacial Electronic Properties Induces Friction Tuning under an Electric Field.

Mysteries about the origin of friction have remained for centuries. Especially, how friction is tuned by an electric field is still unclear. Present tuning mechanisms mainly focus on the atomic configurations and electrostatic force, yet the role of interfacial electronic properties is not fully understood. Here, we investigate a unique friction tuning effect induced by an electric current in a conductive atomic force microscopy experiment and uncover two main tuning mechanisms of friction by the fluctuation of electronic properties during sliding: (1) electric-field-induced electron density redistribution and (2) current-induced electron transfer. We put forward an electronic level friction model unraveling the relationship between the friction tuning and the electronic property fluctuation (EPF) under electric field/current, which is applicable to tribosystems ranging from conductors to semiconductors and insulators, including two-dimensional material interfaces. This model provides theoretical guidance for tribosystem design and friction control, proposing a new perspective in understanding the origin of friction.

Electronic modulation of Ni2P through anion and cation substitution toward highly efficient oxygen evolution

Rationally designed oxygen evolution reaction (OER) catalysts with structural and compositional superiorities are essential for energy-related electrocatalytic techniques. Transition-metal phosphides have been used as promising electrocatalysts for OER. Incorporating heteroatoms into the lattice can induce lattice distortion and redistribution of electron density, consequently modifying the electronic structure and improving catalytic performance. Herein, Fe- and S-substituted Ni2P uniformly dispersed throughout porous carbon substrate (Ni—Fe—P—S@C) was rationally designed through transformation from the pre-synthesized NiFe-metal organic frameworks (NiFe-MOFs) by partial sulfurization and subsequent phosphorization process. Experimental results and density functional theory calculations showed that Fe and S incorporation could modulate the electronic structure of Ni2P and alter the adsorption free energies of reaction intermediates, contributing to admirable electrocatalytic activity and stability toward OER. Notably, the in-situ formed partially oxidized surface was vital to further improve the local environment. This proposed cation- and anion-substitution strategy will bring new inspiration to boost the electrocatalytic performance of transition-metal-based electrocatalysts for energy conversion applications.

Automated iterative Csp3-C bond formation.

Fully automated synthetic chemistry would substantially change the field by providing broadon-demandaccess to small molecules. However, the reactions that can be run autonomously are still limited. Automating the stereospecific assembly of Csp3-C bonds would expand access to many important types offunctional organic molecules1. Previously, methyliminodiacetic acid (MIDA) boronates were used to orchestrate the formation of Csp2-Csp2 bonds and were effective building blocks for automating the synthesis of many small molecules2, but they are incompatible with stereospecific Csp3-Csp2 and Csp3-Csp3 bond-forming reactions3-10. Here we report that hyperconjugative and steric tuning provide a new class of tetramethyl N-methyliminodiacetic acid (TIDA) boronates that are stable to these conditions. Charge density analysis11-13 revealed that redistribution of electron density increases covalency of the N-B bond and thereby attenuates its hydrolysis. Complementary steric shielding of carbonyl π-faces decreases reactivity towards nucleophilic reagents. The unique features of the iminodiacetic acid cage2, which are essential for generalized automated synthesis, are retained by TIDA boronates. This enabled Csp3 boronate building blocks to be assembled using automated synthesis, including the preparation of natural products through automated stereospecific Csp3-Csp2 and Csp3-Csp3 bond formation. These findings will enable increasingly complex Csp3-rich small molecules to be accessed via automated assembly.

Redistribution of electronic density in channels of metal–Organic frameworks for high-performance quasi-solid lithium metal batteries

Metal-organic frameworks (MOFs) have attracted intensive interests as solid electrolytes (SEs) due to their talents in facilitating ion transport and chemical tunability. Developing functional MOFs-based conductors with better capacity for ion transport is greatly favored for solid-state batteries (SSBs). Inspired by the function of electron-withdrawing fluorine for both ion transport and regulating solid electrolyte interphase (SEI) formation, herein, we designed and synthesized two Ce-MOFs (Ce-UiO-66-4F and Ce-UiO-66-4Cl) constructed with halogen-decorated ligands. Both the simulated calculation and experimental results show that the exposed -F or -Cl functional groups in pores can regulate the electron-distribution property in channels and promote ions transport, achieving high ionic conductivity (2.16 × 10−4 S cm−1 at room temperature), wide electrochemical window (4.8 V) and lower interfacial impedance. Moreover, such halogen-decorated MOFs can participate the electrochemical formation of SEI and suppress the growth of lithium dendrites. Benefiting from these advantages, the assembled SSBs exhibit high performances even under high-voltage and high-loading conditions. This work thus provides a universal strategy for developing bifunctional MOFs for promoting ion-conductivity and regulating SEI formation.

A bonding evolution theory study of the reaction between methylidyne radical, CH(X2Π), and cyclopentadiene, C5H6

AbstractIn the present work, bonding evolution theory (BET) is applied to gain insight about the complex reaction between methylidyne radical, CH (X2Π) and cyclopentadiene, C5H6. The novelty of this work is that all reaction pathways take place in the doublet electronic state and an unpaired electron is always present. Therefore, taking the aforementioned reaction as explicative example, we have shown how to apply the BET tool to these kinds of open‐shell systems, by splitting the wavefunctions into the corresponding alpha and beta parts. As an added value, we have included a point‐by‐point description of the algorithm we use to make it available for the readers. Hence, a complete analysis of bond breaking/forming and charge redistribution along the multi‐channels connecting reactants to products via the transition states and intermediates is presented. We show how the BET brings about the representation of the electronic flow in complex molecular rearrangements like the one herein studied, yielding a transparent rationalization based on the electron density redistribution. The present study allows us to conclude that along the different processes giving rise to the benzene product, the breaking of a CC sigma bond initiates the electronic rearrangement in two cases, but not in the third one. The last step in these processes can be described as an initial weakening of the CH bond with a quasi‐hydride formation and a final retro‐transfer of electrons from the quasi‐hydride to the CH bond. On the other hand, in the way to the fulvene product, the breaking of the CC sigma bond takes place after previous electronic redistribution. Neither the last step of the fulvene formation process nor the interesting H transfer described in the second one, can be explained without the wavefunction splitting technique herein detailed and exemplified.

Discretization and Encapsulation of Palladium inside the Cavity of Crown Ether within the Interlayer of Layered Double Hydroxide for Enhanced Activity: A Case Study with Hydrogenation Reaction

AbstractThe activity of the noble metal‐based heterogeneous catalysts is limited by weak metal–support interactions, aggregation, and low surface to volume (S/V) ratio. The activity can be augmented in many ways. Among them, the discretization of the active sites and redistribution of electron density around the metal atom is an important one. In this work, these two phenomena are studied concerning a model reaction, hydrogenation of p‐nitrophenol (p‐NP). Herein, 1,4,7,10,13‐pentaoxacyclopentadecane ether is introduced in the basal space of layered double hydroxide (LDH) to encapsulate noble Pd0 atom inside the cavity of the crown molecule strategically. The modified LDH (Pda‐ECC‐L0.10@in situ CoAl LDH) augments the properties, like, high S/V ratio and nonaggregation of active sites by forming nonagglomerative discrete catalytic (DNSC) sites within the cavity of crown ether in the basal space. The developed catalyst exhibits higher turnover frequency demonstrating the improved activity due to the formed DNSC sites and redistributes electron density around the Pd atoms by LDH layers and crown molecules. Thus, the present material synthesis route can be considered as a stand‐alone method for preparation of the supported sub‐nanometer noble metal catalyst with higher activity and can be exploited for reactions where noble metal catalyst are used.

Hollow Covalent Organic Framework Cages with Zn Ion‐Implantation Promoting Photocatalytic H2 Evolution

AbstractAbstract: Covalent organic frameworks (COFs) are emerging as a class of photocatalyst for solar energy utilization. The separation of photogenerated excitons in COFs is crucial for their photocatalytic performance. Herein, we report a strategy to tune the electronic structure of COFs by implanting Zn ions within the framework to facilitate the separation and utilization of the photoinduced charges. Zn ions are incorporated within the shell of hollow COF cages (Zn@H‐TpPa) by a sacrificial template method with a formation of hollow cages. The implantation of Zn ions within the framework results in a redistribution of electron density and an increment of the polarity of the COF, as evidenced by experimental and computational analyses, and thus contributes to the separation and transport of charge carries. The Zn@H‐TpPa shows enhanced photocatalytic H2 production efficiency as compared to TpPa. The results demonstrate a new way to optimize the electronic structure of COFs for photocatalysis.

Copper(I) halide complexes with n,n’-diallylthiomorpholinium chloride: synthesis and crystal structure

By means of alternating current electrochemical technique, basing on ethanolic solutions of CuCl 2 ·2H 2 O or CuBr 2 and N,N’-diallylthiomorpholinium chloride, the two isostructural s-complexes of [C 4 H 8 NS(C 3 H 5 ) 2 Cu Hal 2 ] composition were obtained in a single crystal form and characterized by X-ray single crystal method: sp. gr. P 2 1 / c , Z = 4, Hal = Cl ( І ) – a = 7.7763(4), b = 13.1892(5), c = 13.1761(6) Å, β = 103.470(5)°, V = 1314.2(1) Å 3 , r calc. = 1.611 g/сm 3 , m (MoK a ) = 2.20 mm −1 , q max. = 28.8°, 10141 measured, 2659 used reflections, R ( F 2 ) = 0.032, S = 1.07; Hal = 1,04Br/0,96Cl ( ІІ ) – a = 7.9771(3), b = 13.2391(5), c = 13.1422(5) Å, β = 103.942(4), V = 1347.1(1) Å 3 , r calc. = 1.80 g/см 3 , m (MoK a ) = 5.02 mm −1 , q max. = 29.0°, 21269 measured, 2772 used reflections, R ( F 2 ) = 0.027, S = 1.08. In the crystal structure of the studied compounds, the trigonal-pyramidal coordination environment of Cu(I) includes sulfur atoms of the organic cation and three chloride anions (compound I ) or chloride/bromide mixture (compound II ). Atoms occupying position Hal (2) perform a bridging function and connect individual coordination polyhedrons into dimeric topological units {L 2 Cu 2 Hal 4 }. These dimers through hydrogen bonding are linked into a three-dimensional framework. None of the available allylic groups of the N,N’-diallylthiomorpholinium cation are coordinated to the copper(I) ion. In our opinion, this feature of the discussed crystal structure of [(C 4 H 8 NS(C 3 H 5 ) 2 )Cu Hal 2 ] compounds is explained by the influence of competition between the sulfur atom and the C=C bond of the allyl group of the cation during complexation in solution and the redistribution of electron density in the crystal structure of solid compounds due to hydrogen contacts C–H… Hal . Keywords : N,N’-diallylthiomorpholinium; copper(І); s-complexes; crystal structure.

Localized Electron Density Redistribution in Fluorophosphate Cathode: Dangling Anion Regulation and Enhanced Na‐Ion Diffusivity for Sodium‐Ion Batteries (Adv. Funct. Mater. 4/2022)

Anionic Doping In article number 2109694, Hong Yu, Cheng-Feng Du, Xing-Long Wu, and co-workers develop Cl-doped Na3V2(PO4)2O2F (NVPO2−xClxF) as superior cathode material for sodium-ion batteries. In NVPO2−xClxF, Cl doping tunes the electronic structure and causes the electron redistribution on vanadium center/dangling anions. As a result, a revised redox behavior of vanadium and increased Na+- diffusivity/electrochemical properties are achieved.

Tracing electron density changes in langbeinite under pressure.

Pressure is well known to dramatically alter physical properties and chemical behaviour of materials, much of which is due to the changes in chemical bonding that accompany compression. Though it is relatively easy to comprehend this correlation in the discontinuous compression regime, where phase transformations take place, understanding of the more subtle continuous compression effects is a far greater challenge, requiring insight into the finest details of electron density redistribution. In this study, a detailed examination of quantitative electron density redistribution in the mineral langbeinite was conducted at high pressure. Langbeinite is a potassium magnesium sulfate mineral with the chemical formula [K2Mg2(SO4)3], and crystallizes in the isometric tetartoidal (cubic) system. The mineral is an ore of potassium, occurs in marine evaporite deposits in association with carnallite, halite and sylvite, and gives its name to the langbeinites, a family of substances with the same cubic structure, a tetrahedral anion, and large and small cations. Single-crystal X-ray diffraction data for langbeinite have been collected at ambient pressure and at 1 GPa using a combination of in-house and synchrotron techniques. Experiments were complemented by theoretical calculations within the pressure range up to 40 GPa. On the basis of changes in structural and thermal parameters, all ions in the langbeinite structure can be grouped into 'soft' (potassium cations and oxygens) and 'hard' (sulfur and magnesium). This analysis emphasizes the importance of atomic basins as a convenient tool to analyse the redistribution of electron density under external stimuli such as pressure or temperature. Gradual reduction of completeness of experimental data accompanying compression did not significantly reduce the quality of structural, electronic and thermal parameters obtained in experimental quantitative charge density analysis.

Localized Electron Density Redistribution in Fluorophosphate Cathode: Dangling Anion Regulation and Enhanced Na‐Ion Diffusivity for Sodium‐Ion Batteries

AbstractPolyanionic transition metal polyphosphate (TMPO)‐type Na3V2(PO4)2O2F (NVPO2F) is promising as cathode for large‐scale sodium‐ion batteries (SIBs) on account of its considerable capacity and highly stable structure. However, the redox of transition metal and phase transitions along with the (de)intercalation of Na+ lead to its slow kinetics and inferior rate performance. Herein, chlorine (Cl) is applied as a heteropical dopant to obtain Cl‐doped NVPO2F (NVPO2−xClxF) cathode material for SIBs. Density functional theory investigation reveals that Cl doping tunes the localized electronic density and structure in NVPO2F lattice, causing the electron redistribution on vanadium center and dangling anions. Hence, the NVPO2−xClxF cathode exhibits a revised redox behavior of vanadium for Na+ extraction/insertion, increases Na+ diffusion rate, as well as lowers charge transfer resistance. A Na+ storage mechanism of reversible transformations between three phases and V4+/V5+ redox couple for NVPO2−xClxF cathode is verified. The NVPO2−xClxF cathode reveals a high rate capacity of ≈63 mAh g−1 at 30C and great cycle stability over 1000 cycles at 10C. More importantly, outstanding rate property (314 Wh kg−1 at 5850 W kg−1) and cycling capability are obtained for the NVPO2−xClxF//3DC@Se full cell. This study demonstrates a brand‐new strategy to prepare advanced cathode materials for superior SIBs.

Spectral profiling, structural, molecular docking and ELF elucidation of bioactive molecule Benzoguanamine

• Computational reports disclose the presence of H- bonding. • Binding affinity of BG with anti-canceral proteins upholds that activity. • Drug likeness achieved to endorses new anti-canceral drug activity. Optimized geometry and vibrational wave numbers of the normal modes of Benzoguanamine (BG) have been investigated using Gaussian’09 at B1B95/6–31 G (d) level. Present work elucidates structural and spectral analysis of the title compound. Redistribution of electron density (ED) in various bonding and antibonding orbitals along with E(2) energies have been calculated by natural bond orbital (NBO) analysis to give clear evidence of stabilization originating from the hyper conjugation of various intra-molecular interactions. HOMO-LUMO analysis has been performed to analyze charge transfer interactions within the molecule. The chemical implication of the molecule was explained using ELF, LOL with contour maps. Molecular docking was performed with various target proteins inorder to confirm the biological activity of compound and drug likeness influences were designed to realize the biological assets of BG.

Selective Enhancement of SERS Spectral Bands of Salicylic Acid Adsorbate on 2D Ti3C2Tx-Based MXene Film

In this research, we have demonstrated that 2D Ti3C2Xn-based MXene (MXene) films are suitable for the design of surface-enhanced Raman spectroscopy (SERS)-based sensors. The enhanced SERS signal was observed for a salicylic acid molecule on Ti3C2Tx-based MXene film. Confirmation of the adsorption of the salicylic acid molecule and the formation of a salicylic acid–MXene complex were determined by experimental SERS-based spectral observations such as greatly enhanced out-of-plane bending modes of salicylic acid at 896 cm−1 and a band doublet at 681 cm−1 and 654 cm−1. Additionally, some other spectral features indicate the adsorption of salicylic acid on the MXene surface, namely, a redshift of vibrational modes and the disappearance of the carboxyl deformation spectral band at 771 cm−1. The determined enhancement factor indicates the value that can be expected for the chemical enhancement mechanism in SERS of 220 for out-of-plane vibrational modes. Theoretical modeling based on density functional theory (DFT) calculations using B3LYP/6311G++ functional were performed to assess the formation of the salicylic acid/MXene complex. Based on the calculations, salicylic acid displays affinity of forming a chemical bond with titanium atom of Ti3C2(OH)2 crystal via oxygen atom in hydroxyl group of salicylic acid. The electron density redistribution of the salicylic acid–MXene complex leads to a charge transfer effect with 2.2 eV (428 nm) and 2.9 eV (564 nm) excitations. The experimentally evaluated enhancement factor can vary from 220 to 60 when different excitation wavelengths are applied.