Conceptual DFT Research Articles

Conceptual DFT study of antioxidant activity of carotenoids and its radicals

Conceptual DFT study of antioxidant activity of carotenoids and its radicals

Comparative Study of Docking Tools for Evaluation of Potential Copper Metallodrugs and Their Interaction with TMPRSS2

COVID-19 has caused over seven million deaths globally due to its high transmission rate. The virus responsible for the disease requires a transmembrane protease serine type II (TMPRSS2-7MEQ) to infiltrate host cells and has been linked to several cancers, particularly prostate cancer. To investigate COVID-19 potential therapies, a series of Casiopeina-like copper complexes containing 1,10-Phenanthroline and amino acids were investigated as TMPRSS2 inhibitors. The molecular structures of twelve Phenanthroline copper complexes were calculated, and their global reactivity indices were analyzed using DFT and conceptual DFT methods. Three molecular docking algorithms were employed to identify the most effective inhibitors by examining their interactions with amino acid residues in the target protein’s catalytic activity triad (Asp345, His296, and Ser441). All complexes are docked above the catalytic site, blocking the interaction with substrates. The Phenanthroline complexes showed better interactions than the Bipyridine complexes, likely due to increased hydrophobic contacts. Analogs’ cationic nature and amino acids’ basic side chains bring them near the active site by interacting with Asp435. The top complexes in this study contain Ornithine, Lysine, and Arginine, making them promising alternatives for researching new drugs for COVID-19 and cancers like prostate cancer.

Exploring chemical reactivity through a combined conceptual DFT and ELF topology approach.

In a proof-of-concept study, we explore how a combined approach using the topology of the electron localization function (ELF) and the condensed dual descriptor (DD) function can guide the optimal orientation between reactants and mimic the potential energy surfaces of molecular systems at the beginning of the chemical pathway. The DD has been chosen for its ability to evaluate the regioselectivity of neutral and soft species and to potentially mimic the interaction energy obtained from the mutual interactions between nucleophilic and electrophilic regions of the building blocks under perturbative theory. Our method has been illustrated with examples in which the optimal orientation of several systems can be successfully identified. The limitations of the presented model in predicting chemical reactivity are outlined in particular the influence of the selected condensation scheme.

IR spectra simulations by anharmonic DFT and CDFT-saturated and unsaturated fatty acids of Siberian sturgeon (Acipenser baerii Brandt,1869)

The Siberian sturgeon is one of the most remarkable species in the field of aquatic biology which also has ecological importance, commercial significance, and nutritional characteristics. The purpose of this study is to determine the fatty acid content of different organs of Siberian sturgeon through both theoretical and experimental techniques to compare oxidative stability of the samples in terms of fatty acid profile. For this purpose, the fatty acid content of flesh, brain, caviar and liver of sturgeon was determined by gas chromatography and the middle infrared spectra of tissues were collected by an infrared spectrofotometer. The fatty acid content of samples was also computed by anharmonic DFT and CDFT calculations using IR spectra. Oleic acid was the most abundant fatty acid in all tissues. All tissues accumulated by docosahexanoic, eicosapentanoic and linolenic acids. The PCA model was able to classified the tissues with respect to fatty acid contents. Comprehensive anharmonic DFT calculations were performed to better understand the fatty acid of samples at the atomistic level and to predict the spectra of more complex food samples with varying fatty acid compositions. Oxidative stabilities of fatty acids were also investigated through Conceptual DFT based computations. Maximum Hardness and Minimum Electrophilicity Principles accurately predicted saturated and unsaturated fatty acids of sturgeon as the experimental data revealed.

On the link between the reaction force constant and conceptual DFT.

The reaction force constant ( ), introduced by Professor Alejandro Toro-Labbé, plays a pivotal role in characterizing the reaction pathway by assessing the curvature of the potential energy profile along the intrinsic reaction coordinate. This study establishes a novel link between and the reactivity descriptors of conceptual density functional theory (c-DFT). Specifically, we derive expressions that relate the reaction force constant to nuclear softness and variations in chemical potential. Our findings indicate that regions of the reaction pathway where is negative match with significant electronic structure rearrangements, while positive regions match mostly with geometric rearrangements. This correlation between and c-DFT reactivity descriptors enhances our understanding of the underlying forces driving chemical reactions and offers new perspectives for analyzing reaction mechanisms. The internal reaction path for the proton transfer in SNOH, chemical potential, and nuclear softness were computed using DFT with B3LYP exchange-correlation functional and 6-311++G(d,2p) basis set.

Cycloadditions of 4-Alkenyl-2-aminothiazoles with Nitroalkenes in the Formal Synthesis of Pramipexole: An Experimental and Computational Study.

4-Alkenyl-2-dialkylaminothiazoles act as in-out dienes in [4 + 2] cycloaddition reactions with nitroalkenes, furnishing 2-amino-6-nitro-4,5,6,7-tetrahydrobenzothiazoles in moderate to good yields, accompanied by a subsequent 1,3-H migration. These transformations proceed with exquisite site-, regio-, and diastereoselectivity. This strategy is further enriched by revealing a novel route for pramipexole synthesis. The examination of the potential energy surfaces associated with the four possible reaction pathways for the Diels-Alder cycloaddition (relative approach of the diene-dienophile and endo/exo approach of the nitro group) not only aligns with experimental observations but also unveils key mechanistic insights. Specifically, computational analyses uncover the favored pathway yielding 6-nitro-4,5,6,7-tetrahydrobenzothiazoles, with some instances proceeding through a two-step mechanism involving a tandem sequence of chemical processes, and the influence of various factors such as dienophile structure and the approach mode of the nitro group. Additionally, the stabilization of the exo-transition states, particularly facilitated by phenyl substitution in the dienophile, is highlighted. Asynchronicity, dipole moment, and other parameters indicative of polar character further characterize these Diels-Alder reactions. Conceptual DFT calculations underscore the pivotal role of the 1,3-thiazole ring in enhancing dienic activation and dictating regioselectivity, emphasizing interactions between the C5 of the thiazole nucleus and the Cβ atom of the nitroalkenes.

Synthesis and antioxidant activity of gallic acid based fluorescent benzothiazole analogue: Photophysical, electrochemical, conceptual DFT, QTAIM and docking investigations

The present investigation reports on the synthesis of a novel 3,4,5-trihydroxy-N-(6‑methoxy benzo[d]thiazol-2-yl)benzamide (TMTB) molecule and employs elemental analysis, 1H NMR, 13C NMR, and mass spectrum methods to determine the structure of the desired product. The experimental and theoretical absorption and emission spectra of the molecules are used to study the photophysical properties of the TMTB molecule. We investigate the in vitro antioxidant activity of TMTB using DPPH and superoxide radical scavenging assays, as well as molecular docking experiments with the target NAD(P)H oxidase (PDB ID: 2CDU) protein. To ascertain the energies of the LUMO and HOMO levels, NLO behaviour, intermolecular charge transport facilitated by global chemical reactivity descriptors, molecular electrostatic potentials (MEP), and hyperpolarizability analyses, an investigation was carried out on their conceptual DFT and QTAIM analyses operating under B3LYP/6–31 G. The simulated DFT calculation shows that TMTB is highly polarizable in both the gas and solvent phases, with HOMO-LUMO energy gaps of 4.18 and 4.24 eV, respectively. Total first and second hyperpolarizability values for TMTB in the gas phase were determined to be 155.09 × 10–30 and 3611.59 × 10–36 esu, respectively, whereas in the DMSO phase the values were 556.15 × 10–30 and 6223.79 × 10–36 esu. Computational studies results corroborate the experimental findings. Based on the photophysical and computational findings, the newly reported TMTB molecule was determined to be a promising candidate for additional optimization and use in optoelectronic devices.

Unveiling the potency of tetrahydropalmitine as a green anticorrosion material for 2024 aluminum alloy in acid-chloride environments

2024 aluminum alloy has garnered attention from researchers because of its numerous applications in the oil and gas, aerospace, and marine sectors. However, its constituent high Cu content (the primary alloying element) poses a significant challenge to its use, particularly in applications that demand high corrosion resistance. This is particularly troubling in oxygen-containing chloride systems. Herein, we developed a protection strategy for 2024 Al alloy in an acid-chloride environment (composed of 0.5 M NaCl and 0.25 M H2SO4) using natural tetrahydropalmitine (THP) isolated from Corydalis yanhusuo. THP was effectively characterized from its 1H NMR, 13C NMR, and FTIR spectra, and its anticorrosion potentials were methodically investigated by electrochemical, gravimetry and theoretical experiments. Upon the addition of THP to the test system, EIS measurements revealed a steady increase in the Nyquist semicircles, as well as the Bode impedance and phase angle plots, attaining an optimum inhibition efficiency of 91.5 % at 2.0 g/L THP. Tafel plots manifested mixed-type anticorrosion effects with dominant cathodic properties, ascribed to the ordered shielding effect of both the hydrogen evolution reaction and the oxidation of oxide-free ions. According to gravimetric corrosion assessment, the 2024 Al alloy mainly retained its protection over time in the presence of THP, exhibiting only minor decline in its protectability. This is attributed to the combined effect of stable oxide film formation and the adsorbed THP on the alloy surface. SEM afforded the proof of THP adsorption on 2024 Al while XPS offered clarity into its anticorrosion mechanism. Conceptual DFT parameters, molecular electrostatic potential and molecular dynamics simulation were used to comprehend the inhibition process of THP on Al surface. Generally, THP was proven to be a viable and sustainable bio-based anticorrosion material for the protection of 2024 Al alloy.

Determining the binding mechanism of B12N12(Zn) with CH4, CO, CO2, H2O, N2, NH3, NO, NO2, O2, and SO2 gases

In this study, an exploration of molecular interactions between CH4, CO, CO2, H2O, N2, NH3, NO, NO2, O2, SO2 gas molecules and B12N12(Zn) nanocage is conducted using advanced computational techniques, ωB97XD/Def2tzvp, unraveling fundamental behaviors. Employing global optimization methods and sophisticated tools like the bee colony algorithm in ABCluster software, the research offers insights into energy adsorption processes, confirming molecular stability through DFT calculations. The determination of electrophilicity index values through conceptual DFT analysis sheds light on relative reactivity levels and charge transfer phenomena, emphasizing that in some cases the nanocage's role as a potential electron acceptor. Natural bond analysis of charge transfer direction and valence shell orbital interactions enriches understanding, supported by comprehensive parameter compilation and critical point visualization. Further confirmation of interaction types and strengths through G(r)/V(r) ratios and ELF values enhances comprehension through quantum theory of atoms in molecule analysis. Ultimately, this study contributes significantly to computational chemistry, laying foundations for molecular design and engineering advancements. It sets the stage for future progress in materials science and catalysis, promising innovation in sustainable energy solutions and technological development.

Understanding the coupling of non-metallic heteroatoms to CO2 from a Conceptual DFT perspective

ContextA Conceptual DFT (CDFT) study has been carry out to analyse the coupling reactions of the simplest amine (CH3NH2), alcohol (CH3OH), and thiol (CH3SH) compounds with CO2 to form the corresponding adducts CH3NHCO2H, CH3OCO2H, and CH3SCO2H. The reaction mechanism takes place in a single step comprising two chemical events: nucleophilic attack of the non-metallic heteroatoms to CO2 followed by hydrogen atom transfer (HAT). According to our calculations, the participation of an additional nucleophilic molecule as HAT assistant entails important decreases in activation electronic energies. In such cases, the formation of a six-membered ring in the transition state (TS) reduces the angular stress with respect to the non-assisted paths, characterised by four-membered ring TSs. Through the analysis of the energy and reaction force profiles along the intrinsic reaction coordinate (IRC), the ratio of structural reorganisation and electronic rearrangement for both activation and relaxation energies has been computed. In addition, the analysis of the electronic chemical potential and reaction electronic flux profiles confirms that the highest electronic activity as well as their changes take place in the TS region. Finally, the distortion/interaction model using an energy decomposition scheme based on the electron density along the reaction coordinate has been carried out and the relative energy gradient (REG) method has been applied to identify the most important components associated to the barriers.MethodsThe theoretical calculation were performed with Gaussian-16 scientific program. The B3LYP-D3(BJ)/aug-cc-pVDZ level was used for optimization of the minima and TSs. IRC calculations has also been carried out connecting the TS with the associated minima. Conceptual-DFT (CDFT) calculations have been carried out with the Eyringpy program and in-house code. The distortion/interaction model along the reaction coordinate have used the decomposition scheme of Mandado et al. and the analysis of the importance of each components have been done with the relative energy gradient (REG) method.

Spin-Polarized Conceptual Density Functional Theory from the Convex Hull.

We present a new, nonarbitrary, internally consistent, and unambiguous framework for spin-polarized conceptual density-functional theory (SP-DFT). We explicitly characterize the convex hull of energy, as a function of the number of electrons and their spin, as the only accessible ground states in spin-polarized density functional theory. Then, we construct continuous linear and quadratic models for the energy. The nondifferentiable linear model exactly captures the simplicial geometry of the complex hull about the point of interest and gives exact representations for the conceptual DFT reactivity indicators. The continuous quadratic energy model is the paraboloid of maximum curvature, which most tightly encloses the point of interest and neighboring vertices. The quadratic model is invariant to the choice of coordinate system (i.e., {N, S} vs {Nα, Nβ}) and reduces to a sensible formulation of spin-free conceptual DFT in the appropriate limit. Using the quadratic model, we generalize the Parr functions {P+(r), P-(r)} (and their derivatives with respect to number of electrons) to this new spin-polarized framework, integrating the Parr function concept into the context of (spin-polarized) conceptual DFT, and extending it to include higher-order effects.

Aromaticity of six-membered nitro energetic compounds through molecular electrostatic potential, magnetic, electronic delocalization and reactivity-based indices

The electron density depletion associated with π-hole at the ring center typical of energetic compounds was clearly revealed by the molecular electrostatic potential (ESP). In addition, the spatial arrangement of NO2 groups appears to affect the ESP value in the ring center, and therefore sensitivity to detonation. Indeed, for monocyclic nitrobenzene compounds with the same number of NO2 groups, the ESP value in the ring center decreases as the NO2 groups are more closely spaced. As expected, the central rings become less aromatic as NO2 groups are added. The MCI, PDI, PLR, NICSzz(1), FLU indices are all strongly correlated with the ESP values observed in the ring center of the set of nitrobenzenes. Aromaticity indices based on electron delocalization criteria appear to be very sensitive to small variations in aromaticity. Among magnetic-based indices, only NICSzz(1) is capable to predict small changes in aromaticity. The PLR index derived from conceptual DFT is quite relevant for predicting small variations in aromaticity. According to our results, the most suitable aromaticity index is not based on a single criterion, and that selecting it is more subtle. Therefore, it is important to combine information from several criteria to obtain a more complete description of the aromaticity of the studied compounds.

Exploring the Reactivity of Donor-Acceptor Systems through a Combined Conceptual and Constrained DFT Approach.

In the context of the conceptual density functional theory (cDFT) and based on the computational efficiency of the constrained DFT (CDFT), we demonstrate that chemical reactivity can be governed by the difference between the local interacting chemical potentials of the reactants (referred as Edual), in agreement with Sanderson's equalization principle. In a proof-of-concept study, we investigated illustrative examples involving typical non-covalent donor-acceptor systems and reactive systems are provided. For the selected systems, our approach reveals significant mimicking between Edual and the DFT-computed intermolecular interaction energy profiles. We further evaluate the influence of the Coulomb and exchange-correlation contributions in Edual. These latter results suggest that numerous potential energy surfaces of clusters can be explored using a Sanderson-like model only based on classical interactions between molecular orbitals domains. To conclude, this study achieved a deeper understanding of the principles of cDFT and assessed, in a wider context, its efficiency in predicting the chemical reactivity.

Unveiling the mechanism and regioselectivity of the [3 + 2] cycloaddition reaction between N-methylphenylnitrone and 1-sulphonyl-1-trifluoromethylallene. A MEDT study

The present study reports within the molecular electron density theory the mechanism and the selectivity of the [3 + 2] cycloaddition (32CA) reaction between an N-methyl-phenylnitrone (nitrone 5) toward the poorest electrophile1-sulphonyl-1-trifluoromethylallene (allene 6) using DFT method at the B3LYP/6-31G(d) theoretical level. Four reactive pathways associated with the ortho and meta regioselective channels and endo and exo stereoselective approaches modes have been explored and characterised. While the formation of the meta/exo cycloadduct as the major isomer proceeds via a stepwise mechanism with the participation of zwitterion intermediate. Whereas, the other three pathways follow a one-step mechanism, the conceptual DFT reactivity indices analysis explains correctly the polar character of this 32CA reaction, and the local Parr functions analysis enables us to explain the meta-regioselectivity observed experimentally. The presence of both trifluromethyl and sulphonyl as electron-withdrawing groups increase markedly the reactivity of the allene and produces the meta selectivity. The inclusion of the solvent effects does not modify the obtained gas-phase selectivities but slightly increases the activation energies as well as the meta-exo stereoselectivity. QTAIM analyse reveal that the presence of significant numbers of conventional and non-conventional interactions at both TSs of the most favourable meta channel is responsible for the complete regioselectivity observed experimentally at this 32CA reaction.

DFT and Molecular Docking Studies of Two Heterocyclic Chalcone Derivatives

AbstractThe newly synthesized heterocyclic chalcone derivatives 3‐(5‐methyl furan‐2‐yl)‐1‐phenyl prop‐2‐en‐1‐one (MFPP) and 1‐(4‐chlorophenyl)‐3‐(5‐methylfuran‐2‐yl) prop‐2‐en‐1‐one (CPMFP) are recently being recognized for their cytotoxicity and anti‐plant pathogenic fungi activities. The quantum chemical calculations for the above‐mentioned compounds have been performed using B3LYP/6‐311++G (d,p) level of theory to get perceptive information about the molecules. After verifying the drug‐likeness of the title compounds, chemical reactivity has been analyzed through frontier molecular orbital analysis. The quantitative and qualitative description of activity at various sites has been investigated through conceptual DFT approach and molecular electrostatic potential surface analyses, respectively. In‐silico bioactivity studies of these compounds with the main protease (6LU7) present in SARS‐CoV‐2 causing COVID‐19, human breast cancer cell line (6VJ3), plant pathogenic fungi R. Solani (4G9N), and G. Zeae (2L2F) have exposed a reasonable binding affinity and inhibition constant with all these targets.

Symmetry and reactivity of π-systems in electric and magnetic fields: a perspective from conceptual DFT.

The extension of conceptual density-functional theory (conceptual DFT) to include external electromagnetic fields in chemical systems is utilised to investigate the effects of strong magnetic fields on the electronic charge distribution and its consequences on the reactivity of π-systems. Formaldehyde, H2CO, is considered as a prototypical example and current-density-functional theory (current-DFT) calculations are used to evaluate the electric dipole moment together with two principal local conceptual DFT descriptors, the electron density and the Fukui functions, which provide insight into how H2CO behaves chemically in a magnetic field. In particular, the symmetry properties of these quantities are analysed on the basis of group, representation, and corepresentation theories using a recently developed automatic program for symbolic symmetry analysis, QSYM2. This allows us to leverage the simple symmetry constraints on the macroscopic electric dipole moment components to make profound predictions on the more nuanced symmetry transformation properties of the microscopic frontier molecular orbitals (MOs), electron densities, and Fukui functions. This is especially useful for complex-valued MOs in magnetic fields whose detailed symmetry analyses lead us to define the new concepts of modular and phasal symmetry breaking. Through these concepts, the deep connection between the vanishing constraints on the electric dipole moment components and the symmetry of electron densities and Fukui functions can be formalised, and the inability of the magnetic field in all three principal orientations considered to induce asymmetry with respect to the molecular plane of H2CO can be understood from a molecular perspective. Furthermore, the detailed forms of the Fukui functions reveal a remarkable reversal in the direction of the dipole moment along the CO bond in the presence of a parallel or perpendicular magnetic field, the origin of which can be attributed to the mixing between the frontier MOs due to their subduced symmetries in magnetic fields. The findings in this work are also discussed in the wider context of a long-standing debate on the possibility to create enantioselectivity by external fields.

DFT investigation of the mechanism and role of N-heterocyclic carbene (NHC) in constructing asymmetric organosilanes using NHC-catalyzed [4+2] cycloaddition reaction.

Herein, the mechanism and origin of stereoselectivity for the asymmetric [4+2] cycloaddition between (E)-3-(p-tolyl)acrylaldehyde (R1) and phenyl-3-(trimethylsilyl)prop-2-en-1-one (R2) in the presence of an N-heterocyclic carbene (NHC) were theoretically scrutinized. The desirable catalytic cycle is characterized by five steps: (1) the coupling reaction of the NHC catalyst with R1, the formation of the Breslow and enolate intermediates in the second and third steps, (4) the formal [4+2] cycloaddition reaction to form the stereoselective C-C bond, and (5) the regeneration of NHC to obtain asymmetric organosilanes. In the most energetically favorable pathway, the formation of the enolate intermediate exhibits the highest energy barrier of about 19.48 kcal mol-1 (Re-TS2BA) and is the rate-determining step. The [4+2] cycloaddition reaction is the stereoselectivity-determining step forming the chiral C-C bond with RR, RS, SR and SS configurations, among which RS is the most desirable configuration. The origin of stereoselectivity was investigated using distortion energy analysis. The first and fourth steps helped in investigating the effects of electron-donating (Me) and electron-withdrawing (Cl) groups on cinnamaldehyde. Conceptual DFT (CDFT) analysis was carried out to confirm the critical role of the NHC catalyst as a Lewis base during the reaction processes.

Temperature and external fields in conceptual density functional theory.

Until quite recently, Conceptual DFT (CDFT) was mainly based on the energy functional, E[N,v], where the number of electrons N and the external potential v are state variables. One of the strengths of CDFT, however, is the ease with which additional and/or different state variables can be incorporated. Here, the incorporation of new variables-namely temperature and external fields-is discussed, outlining the motivation for these extensions, sketching their theoretical/computational context, and presenting some elucidative examples. Using the Grand Canonical Ensemble, finite temperature can be introduced, ameliorating the N-differentiability problem and leading to new well-behaved chemical reactivity concepts. Incorporating temperature as an additional fundamental variable enables us to formulate a novel suite of "thermodynamic" reactivity descriptors, including important concepts like the heat capacity of electronic systems. The mathematical structure underpinning the set of (well-behaved) finite-temperature reactivity indices can guide the formulation of plausible definitions for local analogs of global descriptors. This endeavor is especially significant in the case of local hardness, a concept that has remained elusive since the inception of CDFT. The ever-increasing portfolio of experimental reaction conditions to creatively synthesize new molecules, needs the introduction of various external "fields" like electric and magnetic fields (ε and B), mechanical forces (F) and pressure (P) to describe the state of the chemical system. The conventional energy functional can be expressed in a general form, E[N,v,X], where X denotes the "field". Response functions to changes in the field can then be defined in analogy to classical thermodynamics. The electric field results display a case of a field-induced selectivity in a reaction channel of the Fukui function. Remarkably, atomic electronegativity and hardness in magnetic fields display a piecewise behavior in magnetic fields, associated to configurational jumps upon increasing field strength. The overall compression of their ranges for stronger fields may be insightful when investigating chemistry in extremely high fields. The electronegativity and hardness of diatomics under mechanical force can be traced back to changes in equilibrium distances in the neutral, cationic and anionic state, parallel with the evolution of an intrinsic atomic volume under pressure.

Wandering through quantum-mechanochemistry: from concepts to reactivity and switches.

Mechanochemistry has experienced a renaissance in recent years witnessing, at the molecular level, a remarkable interplay between theory and experiment. Molecular mechanochemistry has welcomed a broad spectrum of quantum-chemical methods to evaluate the influence of an external mechanical force on molecular properties. In this contribution, an overview is given on recent work on quantum mechanochemistry in the Brussels Quantum Chemistry group (ALGC). The effect of an external force was scrutinized both in fundamental topics, like reactivity descriptors in Conceptual DFT, and in applied topics, such as designing molecular force probes and tuning the stereoselectivity of certain types of reactions. In the conceptual part, a brief overview of the techniques introducing mechanical forces into a quantum-mechanical description of a molecule is followed by an introduction to conceptual DFT. The evolution of the electronic chemical potential (or electronegativity), chemical hardness and electrophilicity are investigated when a chemical bond in a series of diatomics is put under mechanical stress. Its counterpart, the influence of mechanical stress on bond angles, is analyzed by varying the strain present in alkyne triple bonds by applying a bending force, taking the strain promoted alkyne-azide coupling cycloaddition as an example. The increase of reactivity of the alkyne upon bending is probed by Fukui functions and the local softness. In the applied part, a new molecular force probe is presented based on an intramolecular 6π-electrocyclization in constrained polyenes operating under thermal conditions. A cyclic process is conceived where ring opening and closure are triggered by applying or removing an external pulling force. The efficiency of mechanical activation strongly depends on the magnitude of the applied force and the distance between the pulling points. The idea of pulling point distances as a tool to identify new mechanochemical processes is then tested in [28]hexaphyrins with an intricate equilibrium between Möbius aromatic and Hückel antiaromatic topologies. A mechanical force is shown to trigger the interconversion between the two topologies, using the distance matrix as a guide to select appropriate pulling points. In a final application, the Felkin-Anh model for the addition of nucleophiles to chiral carbonyls under the presence of an external mechanical force is scrutinized. By applying a force for restricting the conformational freedom of the chiral ketone, otherwise inaccessible reaction pathways are promoted on the force-modified potential energy surfaces resulting in a diastereoselectivity different from the force-free reaction.

Structural, electronic, magnetic, and thermoelectric properties of full-Heusler alloys A2CoS (A=Cu, Zn) for spintronic application via conceptual DFT study

Half metallic ferromagnets play a pivotal role in spintronic applications. Our study focuses on theoretically predicted half metallic ferromagnetic compounds, determined through density functional theory calculations utilizing a first principles approach. The calculations involved the use of Perdew-Burke-Ernzerhof (GGA) and GGA + U exchange correlation energies. Structural analysis revealed the ferromagnetic nature, while electronic properties confirmed the half metallic behavior of these compounds-specifically, Cu2CoS and Zn2CoS. Our findings suggest that within a certain lattice parameter range, both compounds exhibit ferromagnetic behavior. However, beyond this range, Cu2CoS and Zn2CoS do not demonstrate ferromagnetism. Furthermore, our interest lies in examining their thermoelectric behavior using semi-classical Boltzmann transport theory. These results offer valuable insights for leveraging these materials in spintronics applications.