Average Binding Energy Research Articles

Density Functional Theory Study of Structural Evolution, Relative Stability, and Electronic Properties of SnnAln (n = 2–12) Clusters

The ground‐state structure, average binding energy (Eb), fragmentation energies (ΔE), second‐order difference energy (Δ2E), gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital (HOMO‐LUMO), vertical ionization potential (VIP), vertical electron affinity (VEA), and charge transfer of SnnAln (n = 2–12) clusters are evaluated by density functional theory (DFT). With an increase in the cluster size n, Al atoms aggregate in the geometric center of the cluster, and Sn atoms encapsulate Al atoms in the periphery of the cluster. The variation of ΔE, Δ2E, the HOMO‐LUMO gap, VIP, and VEA of the SnnAln clusters follows similar trends, with certain odd–even oscillations. However, beyond the cluster size n ≥ 9, the HOMO‐LUMO gap decreases significantly, and the VIP and VEA fluctuate significantly, indicating a deterioration of the relative stability of the cluster. Charge transfer proceeds from the Sn atom to the Al atom. This study provides an analysis of the interaction between Sn and Al at the atomic level and explains the segregation phenomenon during the preparation of tin‐aluminum alloys.

Characterization of honey-like characteristic aroma compounds in Zunyi black tea and their molecular mechanisms of interaction with olfactory receptors using molecular docking

The important characteristics of honey-like aroma compounds in six Zunyi black tea were determined by gas chromatography-mass spectrometry-olfactometry (GC-MS-O), odor activity value (OAV), gas chromatography-ion mobility spectrometry (GC-IMS) and partial least squares-discriminant analysis (PLS-DA) methods, including geraniol, 2-phenylethyl alcohol, 2-phenyl-2-butenal, furaneol, cinnamaldehyde, ethyl cinnamate, benzoic acid, ethyl pentanoate-M. Furthermore, the molecular docking was used to study the region, site, binding energy, and force of the interaction between the honey-like aroma compounds (geraniol, 2-phenylethyl alcohol, furanol, cinnamaldehyde, and ethyl cinnamate) and olfactory receptors (OR1A1, OR1G1, OR2W1, OR1D2, and OR5M3). The average binding energies of these compounds on the five receptors were −4.34 kcal/mol, −4.14 kcal/mol, −4.24 kcal/mol, −5.08 kcal/mol, and −5.33 kcal/mol, respectively. The experiment indicated the interaction sites of five characteristic compounds and key residues of ORs, such as geraniol and Tyr252 (OR1D2), 2-phenylethyl alcohol and Thr219 (OR1G1), furaneol and Asn155/Ser109 (OR2W1), furaneol and Phe166/Leu164/Val7 (OR5M3), and ethyl cinnamate and Asn155/Asn109 (OR1A1). Further research has found that hydrogen bonding and hydrophobic interactions are important driving forces for the binding of aroma compounds to ORs. By systematically studying the material basis, formation mechanism of honey-like aroma, theoretical guidance can be provided for the regulation of honey-like aroma in Zunyi black tea.

Tuning the hydrogen storage capacity of MOF‐650 by Mg2+/Ca2+ substitution and B, N co‐doped atoms: Grand canonical Monte Carlo simulation and periodic density functional theory

AbstractThis study used periodic density functional theory and grand canonical Monte Carlo simulations to investigate the effects of the co‐doping of B and N atoms and substituting Zn2+ with Mg2+ or Ca2+ in the organic linker groups of MOF‐650. The functionalization increased the polarity of the organic groups, stabilizing the interaction between the MOF and hydrogen molecules. The highest average binding energy of the adsorbed hydrogen in MOF‐650 NB‐C7‐azulene‐Mg was calculated to be −4.75 to 5.40 kcal/mol for the α adsorption sites. Using the substitution of NB azulene and metal cations being Mg2+ or Ca2+, The hydrogen storage capacity of functionalized MOF‐650 was increased to 22 mg/g at 90 bar/298 K, implying the modification strategy of MOF‐650 would strengthen the interaction between MOF frameworks and hydrogen molecules.

Discovery of a series of silicon-based ferrimagnets in CrMnSin (n = 4-20) clusters.

Herein, the structural evolution, electronic and magnetic properties of silicon clusters with two different dopants, CrMnSin (n = 4-20) clusters were investigated at density functional theory (DFT) level. Small-sized CrMnSin (n = 4-9) clusters tend to adopt bipyramid-based geometries, while clusters with sizes n = 10 and 11 prefer to opening cage-like structures. For sizes n = 12 to 14, the half-encapsulated structures gradually transform into closed-cage Cr@Sin structures, with the Mn atom exposed outside. Starting from size 15, both the Cr and Mn atoms are completely encapsulated by silicon atoms. Meanwhile, the Cr and Mn atoms in smaller-sized CrMnSin (n = 4-7) clusters tend to be separated, while they prefer to stay together for larger sizes. Cr atom always acts as electron donor, but not for Mn atom. From the average binding energies, one can conclude that it is easier to form larger size clusters. Smaller and larger sized CrMnSin (n = 4-9 and 19-20) clusters prefer to exhibit ferromagnetic Cr-Mn coupling, while sizes n = 10-18 always exhibit ferrimagnetic state. To our knowledge, the CrMnSin clusters is the first kind of neutral transition-metal doped semiconductor clusters that show ferrimagnetic state within a wide size range.

Multi-targeting of virulence factors of P. aeruginosa by β-lactam antibiotics to combat antimicrobial resistance

Antimicrobial resistance poses a significant challenge to public health, especially in developing countries, due to a substantial rise in bacterial resistance. This situation has become so concerning that we are now at risk of losing the effectiveness of antibiotics altogether. Recent research has firmly established that bacteria engage in a process called quorum sensing (QS). QS regulates various functions, including nutrient scavenging, immune response suppression, increased virulence, biofilm formation and mobility. Pseudomonas aeruginosa, an opportunistic bacterial pathogen, plays a significant role in various medical conditions such as chronic wounds, corneal infections, burn wounds and cystic fibrosis. While antibiotics are effective in killing bacteria, only a few antibiotics, particularly those from the β-lactam group, have been studied for their impact on the quorum sensing of P. aeruginosa. Given the lack of concentrated efforts in this area, we have investigated the role of β-lactam antibiotics on various potential targets of P. aeruginosa. Based on their toxicological profiles and the average binding energy obtained through molecular docking, azlocillin and moxalactam have emerged as lead antibiotics. The binding energy for the docking of azlocillin and moxalactam with LasA was determined to be −8.2 and −8.6 kcal/mol, respectively. Molecular simulation analysis has confirmed the stable interaction of both these ligands with all three target proteins (LasI, LasA and PqsR) under physiological conditions. The results of this research underscore the effectiveness of azlocillin and moxalactam. These two antibiotics may be repurposed to target the quorum sensing of P. aeruginosa. Communicated by Ramaswamy H. Sarma

Novel conjugated microporous polymers for efficient tetracycline adsorption: insights from theoretical investigations

This paper presents a detailed theoretical understanding of the noncovalent interactions between antibiotics tetracycline and conjugated microporous polymer (CMP), which is important to understand the recent experimental finding of efficient removal of antibiotics by CMP materials. We show that the co-work of π-π and H-π interactions determines the final equilibrium structures, when a tetracycline molecule spontaneously adsorbs to the surface or within the pores of the CMP network at physisorption distances. The binding energies for tetracycline/CMP systems are calculated to be −0.31 ∼ −1.15 eV, demonstrating the reliability of the adsorption. The electronic structures of CMP nanostructures remain basically undamaged upon the tetracycline adsorption. The replacement of benzothiadiazole unit with S and N heteroatoms to the phenyl moiety in the linker effectively enhanced the molecular polarity of CMP molecule and increases the interaction area between tetracycline and CMP network, consequently enhancing the average binding energies notably. Our calculations provide useful theoretical guidance for design of novel carbon-based porous adsorbents with good adsorption performance to remove residual tetracycline and other antibiotics in water.

Theoretical Exploration of Properties of Iron-Silicon Interface Constructed by Depositing Fe on Si(111)-(7×7).

Exploring the properties of magnetic metal on the semiconductor surface is of great significance for the application of magnetic recording materials. Herein, DFT calculations are carried out to explore the properties of the iron-silicon interface structures (nFe/DASF) formed by depositing n Fe atoms on the reconstructed Si(111)-(7×7) surface (DASF). The stable nFe/DASF structures are studied in the cases of the adsorption and permeation of Fe atoms on the DASF. In both cases, Fe atoms are not very dispersed and prefer binding with Si atoms rather than the adsorbed Fe atoms, because the Fe-Si interaction is stronger than the Fe-Fe interaction. As the n value increases, the average binding energy (Eb_ave) of Fe generally firstly becomes more negative and then becomes less negative, with the presence of a 7Fe wheel as a stable geometry on the upmost surface. The presence of the 7Fe wheel is attributed to the enhanced Fe-Si interaction in this wheel compared to other geometries. CO adsorption occurs at the central Fe site of the 7Fe wheel which is greatly influenced by the surrounding Si atoms but is little influenced by the additional Fe atoms in the interlayer.

Modulating Wnt/β-Catenin Signaling Pathway on U251 and T98G Glioblastoma Cell Lines Using a Combination of Paclitaxel and Temozolomide, A Molecular Docking Simulations and Gene Expression Study.

One of the most lethal cancers, glioblastoma (GBM), affects 14.5% of all central nervous system (CNS) tumors. Patients diagnosed with GBM have a meager median overall survival (OS) of 15 months. Extensive genetic analysis has shown that many dysregulated pathways, including the Wnt/β-catenin signaling system, contribute to the pathogenicity of GBM. Paclitaxel (PTX) and temozolomide (TMZ) are recognized to have therapeutic potential in several types of cancer, including GBM. This work aimed to examine the impact of PTX and TMZ on the human glioma cell lines U251 and T98G using molecular docking simulations and gene expression profiles in the Wnt/β-catenin signaling pathway. Standard procedure for Molecular Docking simulation, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cytotoxicity assay, and Flow Cytometry assay was used. Genes implicated in the Wnt/β-catenin signaling pathway, including Dvl, Axin, APC, β-catenin, and glycogen synthase kinase3-β (GSK3β), were subjected to real-time PCR. The estimated parameters for targets revealed that the average binding energy and inhibition constant (Ki) for the DVL, β-Catenin, and GSK3β, when targeted by PTX, were - 5.01 kcal/mol, - 5.4 kcal/mol, and - 9.06 kcal/mol, respectively. This energy range was - 6.34 kcal/mol for DVL, - 5.52 kcal/mol for β-Catenin, and - 5.66 kcal/mol for GSK3β as a result of TMZ's inhibitory actions. Gene expression analyses indicated that PTX and PTX/TMZ suppressed GSK3β (p < 0.05). GSK3β from the Wnt/β-catenin signaling pathway was significantly targeted by PTX alone, and adding TMZ to PTX may improve the efficacy of glioblastoma treatment. In addition, the GSK3β gene may help GBM therapy strategies as a potential PTX target.

Hydrogen storage in Sc-decorated Ψ-graphene via density functional theory simulations

Efficient methods and materials to store hydrogen onboard in light-duty fuel cell vehicles is crucial to move away from fossil fuels in the transport sector. Metal-decorated carbon materials are considered as promising materials for hydrogen storage. In this regard, using density functional theory (DFT) simulations incorporating the generalized gradient approximation functional along with the DFT-D2 dispersion correction scheme, we predict that Sc-decorated Ψ-graphene is a promising hydrogen storage material. The Sc atom binds strongly to Ψ-graphene (binding energy ∼3.02 eV), and binds seven H2, with an average binding energy of −0.36 eV/H2 and desorption temperature of ∼400 K. The hydrogen storage capacity with five and seven H2 is 8.59 and 14.46 wt%, respectively, which achieves the requirements of the U. S. Department of Energy for an efficient, onboard and reversible hydrogen storage material in light fuel cell vehicles. The system is stable at room temperature, as verified by ab initio molecular dynamics simulations. The likelihood of Sc–Sc clustering is low due to the high diffusion energy barrier of Sc over the Ψ-graphene surface. Thus, we predict that Sc-doped Ψ-graphene is an excellent reversible hydrogen storage material.

Cheminformatics Strategies Unlock Marburg Virus VP35 Inhibitors from Natural Compound Library.

The Ebola virus and its close relative, the Marburg virus, both belong to the family Filoviridae and are highly hazardous and contagious viruses. With a mortality rate ranging from 23% to 90%, depending on the specific outbreak, the development of effective antiviral interventions is crucial for reducing fatalities and mitigating the impact of Marburg virus outbreaks. In this investigation, a virtual screening approach was employed to evaluate 2042 natural compounds for their potential interactions with the VP35 protein of the Marburg virus. Average and worst binding energies were calculated for all 20 poses, and compounds that exhibited binding energies <-6 kcal/mol in both criteria were selected for further analysis. Based on binding energies, only six compounds (Estradiol benzoate, INVEGA (paliperidone), Isosilybin, Protopanaxadiol, Permethrin, and Bufalin) were selected for subsequent investigations, focusing on interaction analysis. Among these selected compounds, Estradiol benzoate, INVEGA (paliperidone), and Isosilybin showed strong hydrogen bonds, while the others did not. In this study, the compounds Myricetin, Isosilybin, and Estradiol benzoate were subjected to a molecular dynamics (MD) simulation and free binding energy calculation using MM/GBSA analysis. The reference component Myricetin served as a control. Estradiol benzoate exhibited the most stable and consistent root-mean-square deviation (RMSD) values, whereas Isosilybin showed significant fluctuations in RMSD. The compound Estradiol benzoate exhibited the lowest ΔG binding free energy (-22.89 kcal/mol), surpassing the control compound's binding energy (-9.29 kcal/mol). Overall, this investigation suggested that Estradiol benzoate possesses favorable binding free energies, indicating a potential inhibitory mechanism against the VP35 protein of the Marburg virus. The study proposes that these natural compounds could serve as a therapeutic option for preventing Marburg virus infection. However, experimental validation is required to further corroborate these findings.

Spatial Heterogeneity of Biexcitons in Two-Dimensional Ruddlesden-Popper Lead Iodide Perovskites.

Quantum confinement in two-dimensional (2D) Ruddlesden-Popper (RP) perovskites leads to the formation of stable quasi-particles, including excitons and biexcitons, the latter of which may enable lasing in these materials. Due to their hybrid organic-inorganic structures and the solution phase synthesis, microcrystals of 2D RP perovskites can be quite heterogeneous, with variations in excitonic and biexcitonic properties between crystals from the same synthesis and even within individual crystals. Here, we employ one- and two-quantum two-dimensional white-light microscopy to systematically study the spatial variations of excitons and biexcitons in microcrystals of a series of 2D RP perovskites BA2MAn-1PbnI3n+1 (n = 2-4, BA= butylammonium, MA = methylammonium). We find that the average biexciton binding energy of around 60 meV is essentially independent of the perovskite layer thickness (n). We also resolve spatial variations of the exciton and biexciton energies on micron length scales within individual crystals. By comparing the one-quantum and two-quantum spectra at each pixel, we conclude that biexcitons are more sensitive to their environments than excitons. These results shed new light on the ways disorder can modify the energetic landscape of excitons and biexcitons in RP perovskites and how biexcitons can be used as a sensitive probe of the microscopic environment of a semiconductor.

Carbon doping of B6N6 monolayer can improve its hydrogen storage performance effectively: A theoretical study

In this paper, a new two-dimensional B6N6 monolayer is investigated as a type of promising material for hydrogen storage. The average binding energy between Lithium and BN monolayer will be significantly increased from 0.80 eV to 2.42 eV and the metal agglomeration is also effectively avoided by the substitution of one nitrogen atom with one carbon atom. We use Density functional computations to check the hydrogen adsorption properties and find up to ten hydrogen molecules will be adsorbed on the double side Lithium decorated BNC monolayer with the adsorption energy of per H2 from 0.19 eV to 0.27 eV. The maximum storage gravimetric capacity of hydrogen can reach to 11.1 wt%. Meanwhile, the molecular dynamics (MD) calculations confirm that the 10H2@Li-decorated BNC structure is still thermodynamic stable. In addition, the simulation results of Grand Canonical Monte Carlo (GCMC) further prove that the hydrogen gravimetric density (HGD) is expected to reach to 7.48 wt% at room temperature (298 K).

Structural Evolution and Electronic Properties of Two Sulfur Atom-Doped Boron Clusters.

We present a theoretical study of structural evolution, electronic properties, and photoelectron spectra of two sulfur atom-doped boron clusters S2Bn0/- (n = 2-13), which reveal that the global minima of the S2Bn0/- (n = 2-13) clusters show an evolution from a linear-chain structure to a planar or quasi-planar structure. Some S-doped boron clusters have the skeleton of corresponding pure boron clusters; however, the addition of two sulfur atoms modified and improved some of the pure boron cluster structures. Boron is electron-deficient and boron clusters do not form linear chains. Here, two sulfur atom doping can adjust the pure boron clusters to a linear-chain structure (S2B20/-, S2B30/-, and S2B4-), a quasi-linear-chain structure (S2B6-), single- and double-chain structures (S2B6 and S2B9-), and double-chain structures (S2B5, and S2B9). In particular, the smallest linear-chain boron clusters S2B20/- are shown with an S atom attached to each end of B2. The S2B2 cluster possesses the largest highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap of 5.57 eV and the S2B2- cluster possesses the largest average binding energy Eb of 5.63 eV, which shows the superior chemical stability and relative stability, respectively. Interestingly, two S-atom doping can adjust the quasi-planar pure boron clusters (B7-, B10-, and B120/-) to a perfect planar structure. AdNDP bonding analyses reveal that linear S2B3 and planar SeB11- have π aromaticity and σ antiaromaticity; however, S2B2, planar S2B6, and planar S2B7- clusters have π antiaromaticity and σ aromaticity. Furthermore, AdNDP bonding analyses reveal that planar S2B4, S2B10, and S2B12 clusters are doubly (π and σ) aromatic, whereas S2B5-, S2B8, S2B9-, and S2B13- clusters are doubly (π and σ) antiaromatic. The electron localization function (ELF) analysis shows that S2Bn0/- (n = 2-13) clusters have different electron delocalization characteristics, and the spin density analysis shows that the open-shell clusters have different characteristics of electron spin distribution. The calculated photoelectron spectra indicate that S2Bn- (n = 2-13) have different characteristic peaks that can be compared with future experimental values and provide a theoretical basis for the identification and confirmation of these doped boron clusters. Our work enriches the new database of geometrical structures of doped boron clusters, provides new examples of aromaticity for doped boron clusters, and is promising to offer new ideas for nanomaterials and nanodevices.

Adsorption of SO, CO, O2, and N2 on the most stable small Fe clusters

Electronic, structural, and magnetic properties of small Fen aggregates with n < 15 atoms were investigated in the framework of the density functional theory (DFT). Our results indicate that spin–orbit coupling has little effect on the structural properties. The magnetic moment of each atom in the cluster is greater than the magnetic moment of their bulk material and the average binding energy value rises monotonically with the size of the cluster and approaches the bulk value. As well as Fe7 and Fe13 are the two first magic numbers in good agreement with experimental reports. We studied the adsorption of diatomic SO, CO, O2, and N2 molecules on the Fe7 and Fe13 nanoclusters. The most stable adsorption sites, binding energies, and the effect of adsorption on the electronic properties of the Fe clusters were studied. The different aspects of the adsorption mechanism were also investigated. The interaction intensity order is SO, O2, CO, and N2, and the bond length of the molecules increased after adsorption. X@Fe13 (X = SO, O2, CO, and N2) systems represent higher magnetization compared to the X@Fe7 systems. The maximum effect of absorption on the magnetization of the Fe13 cluster was about 2.4% and on the Fe7 cluster was about 9.6%. These results provide insights into the application of iron-based catalysts and the understanding of the real reactions and experimental reports.

Hydrogen storage in Na decorated heteroborospherene Si4B32: Insights from density functional study

This article investigates the structural stability and hydrogen adsorption performance of Na-decorated heteroborospherene Si4B32 using density functional theory (DFT) methods. DFT calculations demonstrate that six sodium (Na) atoms can successfully and chemically bind to the surface of heteroborospherene Si4B32, exhibiting a substantial average binding energy of 2.465 eV without clustering. Moreover, the resulting Na6Si4B32 structure retains its integrity even after absorbing up to 30 hydrogen (H2) molecules, with an average adsorption energy of 0.251 eV/H2. Utilizing DFT analysis, the gravimetric density of Na6Si4B32·(H2)30 can reach 9.143 wt%. Additionally, employing ab initio molecular dynamics (AIMD) simulations, we find that a significant fraction of the H2 molecules desorb from Na6Si4B32 at 300K within 1000 fs. These findings establish the potential of Na-decorated heteroborospherene Si4B32 as a promising candidate for reversible hydrogen storage. The successful binding of Na atoms without clustering and the substantial H2 adsorption capacity, coupled with the structural stability and facile H2 desorption observed at moderate temperatures, highlight the viability of this material for practical hydrogen storage applications.

Structure and stability of Cu-doped Bn (n = 1–12) clusters: DFT calculations

The structural and stability properties of Cu-doped boron clusters (BnCu with n = 1–12) are investigated by the SCG (systematic growth algorithm) method in combination with density functional theory (DFT) calculations. The lowest-energy structures of BnCu clusters show similar arrangements with peripheral Cu-doping on preceding pure Bn clusters. Planar and quasi-planar structures are found for n = 3–6 and n = 10–12 while three-dimensional for n = 7–9. The relative stability of the clusters is further analyzed through the average binding energy, the first and second-order energy differences. The results show that B3Cu, B5Cu, B8Cu and B11Cu, are the most stable clusters. The electronic properties such as the ionization potential and electron affinity are calculated and compared with available experimental data. BnCu clusters with even number of boron atoms show higher electron affinities. The bonding character of the clusters is discussed.

Making Sense of the Growth Behavior of Ultra-High Magnetic Gd2-Doped Silicon Clusters

The growth behavior, stability, electronic and magnetic properties of the Gd2Sin− (n = 3–12) clusters are reported, which are investigated using density functional theory calculations combined with the Saunders ‘Kick’ and the Artificial Bee Colony algorithm. The lowest-lying structures of Gd2Sin− (n = 3–12) are all exohedral structures with two Gd atoms face-capping the Sin frameworks. Results show that the pentagonal bipyramid (PB) shape is the basic framework for the nascent growth process of the present clusters, and forming the PB structure begins with n = 5. The Gd2Si5− is the potential magic cluster due to significantly higher average binding energies and second order difference energies, which can also be further verified by localized orbital locator and adaptive natural density partitioning methods. Moreover, the localized f-electron can be observed by natural atomic orbital analysis, implying that these electrons are not affected by the pure silicon atoms and scarcely participate in bonding. Hence, the implantation of these elements into a silicon substrate could present a potential alternative strategy for designing and synthesizing rare earth magnetic silicon-based materials.

Geometries, Electronic Structures, and Energetic Parameters of the first-row transition metal doped aluminum clusters Al16M

A theoretical study of geometry, stability, electronic structure, and magnetic property of neutral Al16M clusters with M being a first-row 3d transition metal atom, including Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn, are investigated in this theoretical study using quantum chemical approaches. The neutral Al16M clusters favor three kind of structures based on pure Al17 framework, including two exohedral doped isomers and one endohedral doped structure. There is a competition between the endoheral and the exohedral structures of Al16M with M being Ni, Cu, and Zn. The thermodynamic stability of encapsulated structure Al16Ni is confirm by the calculated average binding energy and embedded energy values. DFT calculation, however, indicate that the transition metal doping reduces the ionization potential of the pure aluminum clusters. Based on NBO calculations, a comprehensive picture of magnetic behavior is shown for Al16M clusters. Remarkably, the magnetism of the encapsualated Ni dopant is quenched in Al16 cage. Moreover, NBO calculations found that the 50-electron shells are completely preserved in both clusters Al16Sc and Al­16Ti and the remaining unpaired electron(s) localize(s) mainly on 3d atomic orbitals of the transition metal dopant.

Structure and stability of Mo-doped Cun (n = 1–12) clusters: DFT calculations

The thermodynamic and chemical stability of CunMo (n = 1–12) clusters are evaluated by density functional theory (DFT) calculations. The most stable structures are obtained by using the SCG (systematic growth algorithm) and corroborated by simulated annealing. The lowest-energy structures of CunMo clusters are planar and quasiplanar for n = 3–7, while icosahedral-like structures for n = 8–12. The relative stability of the clusters is further analyzed through the average binding energy, the fragmentation energy and second-order energy differences. The results of EB shows that doping with Mo slightly reduces the stability of small clusters with n = 1–7, however, for n = 8 onward, the doped clusters become more stable due to the formation of the icosahedral structure at Cu12Mo. The results show that Cu4Mo, Cu7Mo, Cu9Mo and Cu12Mo, are more stable than the neighbor clusters. In addition, the doped clusters show higher HOMO–LUMO gaps and total spin magnetic moments compared to pure Cun clusters. The IR spectra of the clusters are provided.

Synthesis, characterization, crystal structure, in silico and computational studies on a novel Schiff base derived from α-chlorocinnamaldehyde and 4-aminoantipyrine

Schiff base, 4-(((1E,2Z)-2‑chloro-3-phenylallylidene)amino)-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one (1) was synthesized by condensation reaction of 4-aminoantipyrine and α-chlorocinnamaldehyde. The compound was characterized using Fourier-transform infrared spectroscopy (FT-IR), ultraviolet (UV)-visible spectroscopy, proton and carbon nuclear magnetic resonance spectroscopy (1H/13C NMR) and single-crystal X-ray diffraction analysis (SC-XRD). Density functional theory (DFT) was used to compute molecular parameters and also compared them with experimental data. The X-ray diffraction data revealed that the compound crystallizes as a monoclinic crystal system with a space group of C2/c and Z = 8, and is stabilized by C12–H12⋯O1, and C8–H8A⋯O1 intramolecular hydrogen bonds. The presence of a distinctive azomethine C = N bond length N3-C12 of 1.283(3) Å, and 1640 cm−1 stretching vibration in the FT-IR spectrum are evidence of the formation of a Schiff base. The computational result indicates that the ionization energy (IE), and electron affinity (EA) values for the molecule are 4.025 and 2.110 eV, respectively. The positive value of EA suggests that the addition of an electron to the molecule would be an exothermic process. The evaluated energy is relatively low and is an expression of the ease of electron transfer from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO). Hirsfeld surface map over dnorm and curvedness surface indicated the presence of π-π stacking while the shape factor index suggests donor and acceptor intermolecular CH—π. Analysis of Hirsfeld surfaces concerning the fingerprint indicated a minimal contribution from the de−di pair and reveals H—-H as a major contribution to the Hirsfeld surface. However, the molecular packing did not confirm H—-H as a significant contributor the packing. Docking calculations on the compound showed average theoretical binding energies toward aromatase (–5.99 ± 0.34 kcal/mol) and fibroblast growth factor receptor (FGFR) (–17.57 ± 6.85 kcal/mol), indicating binding interactions with both protein targets.