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Computations have been performed on V x O y clusters (with x  = 1–8, y  = 1–21) to explore their structure, stability, and reactivity based on local and global reactivity descriptors defined within the formalism of density functional theory (DFT). The vertical and adiabatic ionization energies and electron affinities are in accordance with Franck–Condon principle and suggest that the V x O y clusters are more likely to be electron acceptors than donors. The structure and reactivity of V x O y clusters delicately depend on their oxygen content and environment. Distinct active sites have been identified for each cluster species on the basis of coordination, symmetry, and charge distribution. The propensity of all the reactive sites towards an approaching electrophile and/or nucleophile has been studied using local reactivity descriptor. In oxygen-poor clusters, the vanadium atoms are more prone to nucleophilic attack. With an increase in oxygen concentration, the coordination number of vanadium increases and reaches four-fold, the site for nucleophilic attack shifts to terminal oxygens. We conclude that of all the stoichiometries, the stable V x O y clusters have the (VO 3 ) a (V 2 O 5 ) b formula unit . The localization of positive charge density in cubic cage structure of V 8 O 20 successfully traps halide ions (F − , Cl − , and Br − ). In view of increasing use of metal oxide clusters in heterogeneous catalysis, the understanding of structure-activity relationship in vanadium oxides’ clusters provided in the current study is highly desirable.

At present, alloys have broad application prospects in heterogeneous catalysis, due to their various catalytic active sites produced by their vast element combinations and complex geometric structures. However, it is the diverse variables of alloys that lead to the difficulty in understanding the structure‐property relationship for conventional experimental and theoretical methods. Fortunately, machine learning methods are helpful to address the issue. Machine learning can not only deal with a large number of data rapidly, but also help establish the physical picture of reactions in multidimensional heterogeneous catalysis. The key challenge in machine learning is the exploration of suitable general descriptors to accurately describe various types of alloy catalysts, which help reasonably design catalysts and efficiently screen candidates. In this review, several kinds of machine learning methods commonly used in the design of alloy catalysts is introduced, and the applications of various reactivity descriptors corresponding to different alloy systems is summarized. Importantly, this work clarifies the existing understanding of physical picture of heterogeneous catalysis, and emphasize the significance of rational selection of universal descriptors. Finally, the development of heterogeneous catalytic descriptors for machine learning are presented. This review briefly retrospects the applications of machine learning methods in various alloy catalyst systems, and summarizes several representative categories of descriptors for various alloy catalysts. Based on the machine learning scheme, not only the existing understanding of the physical picture in the study of heterogeneous catalysis is clarified, but also the significance of rational selection of descriptors is emphasized.

Due to its appealing qualities, such as its miniature size and the ability to modify physical properties through chemical synthesis and molecular design, polymer material offers considerable advantages over traditional inorganic material-based electronics. Conjugate polymers are particularly interesting because of their molecular design capabilities, which enable the synthesis of conducting polymers with a variety of ionization potentials and electron affinities (EA), and their ability to control the energy gap and electronegativity (χ). Accordingly, density functional theory (DFT) at the B3LYP/SDD model was used to present possible interactions between polyaniline (PANi) and both alkali and heavy metal oxides. Total dipole moment (TDM), HOMO–LUMO band gap energy (ΔE), ionization energy (IE), EA, chemical hardness (η), chemical potential (μ), electrophilicity index (ω), chemical softness (S), and χ are calculated. TDM of PANi increased while ΔE decreased due to functionalization. The distribution of electronic charge density in molecular electrostatic potential (MESP) maps together with the results of ω reflected the electrophilic nature. The obtained results confirmed that the addition of metal oxides significantly improves the TDM, ΔE, and reactivity descriptors. A strong correlation between the experimental and calculated IR spectra was observed. Additionally, PANi–2MgO and PANi–2MnO model molecules exhibited the highest reactivity. Accordingly, PANi functionalized with MgO and MnO are promising candidates for energy storage devices.

Modern laboratory medicine relies on analytical instruments for bacterial detection, focusing on biosensors and optical sensors for early disease diagnosis and treatment. Thus, Density Functional Theory (DFT) was utilized to study the reactivity of glycine interacted with metal oxides (ZnO, MgO, and CaO) for bacterial detection. Total dipole moment (TDM), frontier molecular orbitals (FMOs), FTIR spectroscopic data, electronic transition states, chemical reactivity descriptors, nonlinear optical (NLO) characteristics, and molecular electrostatic potential (MESP) were all investigated at the B3LYP/6–31G(d, p) level using DFT and Time-Dependent DFT (TD-DFT). The Coulomb-attenuating approach (CAM-B3LYP) was utilized to obtain theoretical electronic absorption spectra with the 6-31G(d, p) basis set to be more accurate than alternative quantum chemical calculation approaches, showing good agreement with the experimental data. The TDM and FMO investigation showed that glycine/CaO model has the highest TDM (10.129Debye) and lowest band gap (1.643 eV). The DFT computed IR and the experimental FTIR are consistent. The calculated UV-vis spectra showed a red shift with an increase in polarity following an increase in the absorption wavelength due to the interaction with ZnO, MgO, and CaO. Among the five solvents of water, methanol, ethanol, DMSO and acetone, the water and DMSO enhances the UV-Vis absorption. Glycine/CaO model showed high linear polarizability (14.629 × 10 −24 esu) and first hyperpolarizability (23.117 × 10 −30 esu), indicating its potential for nonlinear optical applications. The results showed that all model molecules, particularly glycine/CaO, contribute significantly to the development of materials with potential NLO features for sensor and optoelectronic applications. Additionally, MESP confirmed the increased electronegativity of the studied structures. Additionally, glycine/ZnO nanocomposite was synthesized and characterized using IR and UV-visible spectroscopy to determine their structural and spectroscopic features. It was discovered that there was good agreement between the DFT computed findings and the related experimental data. The antibacterial activity of glycine/ZnO nanocomposites against Staphylococcus aureus ( S. aureus) and Pseudomonas aeruginosa were studied in terms of concentration and time. The results showed that increasing the concentration of glycine/ZnO nanocomposite significantly enhanced its antibacterial efficacy by lowering optical density. Notably, Pseudomonas aeruginosa exhibited lower susceptibility to the nanocomposite compared to S. aureus , requiring higher concentrations for effective bactericidal action. In summary, this study contributes novel insights into the dual functionality of glycine-metal oxide complexes, with significant implications as optical biosensor for microbial detection.

In this study, we report the synthesis of a new organic–inorganic molecular salt of the clinically used antifungal drug fluconazole, (H2Fluconazole).SnCl6.2H2O. By detailed investigation and analysis of its structural properties, we show that the structure represents a 0D structure built of alternating organic and inorganic zig-zag layers along the crystallographic c-axis and the primary supramolecular synthons in this salt are hydrogen bonding, F···π and halogen bonding interactions. Magnetic measurements reveal the co-existence of weak ferromagnetic behavior at low magnetic field and large diamagnetic contributions, indicating that the synthesized material behaves mainly as a diamagnetic material, with very low magnetic susceptibility and with a band gap energy of 3.6 eV, and the salt is suitable for semiconducting applications. Extensive theoretical study is performed to explain the acceptor donor reactivity of this compound and to predict the Cl-substitution effect by F, Br and I. The energy gap, frontier molecular orbitals (FMOs) and the different chemical reactivity descriptors were evaluated at a high theoretical level. Calculations show that Cl substitution by Br and I generates compounds with more important antioxidant ability and the intramolecular charge transfer linked to the inorganic anion.

A methodology based on the concepts that arise from Density Functional Theory named Conceptual Density Functional Theory (CDFT) was chosen for the calculation of some global and local reactivity descriptors of the Discodermins A–H family of marine peptides through the consideration of the KID (Koopmans in DFT) technique that was successfully used in previous studies of this kind of molecular systems. The determination of active sites of the studied molecules for different kinds of reactivities was achieved by resorting to some CDFT-based descriptors like the Fukui functions as well as the Parr functions derived from Molecular Electron Density Theory (MEDT). A few properties identified with their ability to behave as a drug and the bioactivity of the peptides considered in this examination were acquired by depending on a homology model by studying the correlation with the known bioactivity of related molecules in their interaction with various biological receptors. With the further object of analyzing their bioactivity, some parameters of usefulness for future QSAR studies, their predicted biological targets, and the ADME (Absorption, Distribution, Metabolism, and Excretion) parameters related to the Discodermins A–H pharmacokinetics are also reported.

In this computational investigation, the effect of decoration of graphene oxide (GrO) with three different species FeO, SO, and NO modulates its electronic structure and reactivity for potential electrode and sensing applications. All model structures (pristine graphene, GrO, GrO/FeO, GrO/SO, and GrO/NO) were optimized at the B3LYP/LANL2MB level of theory. We analyzed total dipole moments (TDM), HOMO/LUMO energy gaps (ΔE), global reactivity descriptors (I, A, µ, η, S, ω), density of states (DOS and PDOS), molecular electrostatic potential (MESP), Quantum Theory of Atoms in Molecules (QTAIM) topologies, and noncovalent interaction (NCI) patterns. Oxidation from Gr to GrO created a modest dipole moment (3.06 Debye) and reduced ΔE from 4.483 eV to 3.226 eV. Decoration with FeO raised the TDM to 14.26 Debye and decreased ΔE to 1.625 eV, while SO decoration yielded the largest TDM (20.38 Debye) and the smallest gap (0.576 eV). In contrast, NO decoration produced intermediate values (TDM = 2.90 Debye, ΔE = 2.412 eV). Global reactivity descriptors confirm that GrO/FeO and GrO/SO acquire strong electrophilic character and high softness, and GrO/NO retains moderate reactivity. DOS/PDOS analysis shows that Fe, S, and N introduce new states near the Fermi level, facilitating charge transfer. MESP maps identify electron-rich and -poor regions at functional sites, while QTAIM indicates a covalent Fe–O bond in GrO/FeO and hydrogen-bonding interactions in GrO/SO and GrO/NO. NCI analysis further supports the presence of van der Waals interactions at the decoration interfaces. Taken together, our results demonstrate that choice of decorating species enables precise tuning of GrO’s electronic and reactive properties, highlighting GrO/FeO and especially GrO/SO as promising candidates for enhanced electrode performance and gas sensing.

The position of conceptual density functional theory (CDFT) in the history of density functional theory (DFT) is sketched followed by a chronological report on the introduction of the various DFT descriptors such as the electronegativity, hardness, softness, Fukui function, local version of softness and hardness, dual descriptor, linear response function, and softness kernel. Through a perturbational approach they can all be characterized as response functions, reflecting the intrinsic reactivity of an atom or molecule upon perturbation by a different system, including recent extensions by external fields. Derived descriptors such as the electrophilicity or generalized philicity, derived from the nature of the energy vs. N behavior, complete this picture. These descriptors can be used as such or in the context of principles such as Sanderson’s electronegativity equalization principle, Pearson’s hard and soft acids and bases principle, the maximum hardness, and more recently, the minimum electrophilicity principle. CDFT has known an ever-growing use in various subdisciplines of chemistry: from organic to inorganic chemistry, from polymer to materials chemistry, and from catalysis to nanotechnology. The increasing size of the systems under study has been coped with thanks to methodological evolutions but also through the impressive evolution in software and hardware. In this flow, biosystems entered the application portfolio in the past twenty years with studies varying (among others) from enzymatic catalysis to biological activity and/or the toxicity of organic molecules and to computational peptidology. On the basis of this evolution, one can expect that “the best is yet to come”.

The anticancer activity of 3′-deoxyadenosine (Cordycepin, or dCor) is known to be linked to the inhibition of the MAPK/ERK signalling and Hedgehog pathways, as well as the termination of primer elongation by primase in DNA lagging-strand synthesis. In this study, the electronic properties of dCor, 7,8-dihydro-8-oxo-3′-deoxyadenosine (OXOdCor), and 8-hydroxy-3′deoxyadenosie (HOdCor), together with their spin densities, charge distributions, and global reactive descriptors, have been taken into consideration at the M06-2x/6-31++G** level of theory in the aqueous phase. It was found that dCor predominantly adopts a 3′-endo,anti conformation, while OXOdCor and HOdCor adopt a 2′-endo,syn conformation. Also, the keto form of oxidised dCor was found to be energetically preferred to its enolic form. The adiabatic ionisation potentials (AIPs) were noted as follows (in eV): 6.29 for dCor, 6.21 for OXOdCor, and 6.17 for HOdCor. The lowest adiabatic electron affinity among all the discussed adenine nucleosides analogues was assigned for OXOdCor at 1.12 eV. A thorough analysis of the spin density distribution of the adiabatic radical cation reveals that it has a higher accumulation at N6 > C5 > C8 > 3 of dCor, C5 > N6 > N7 > O8 of OXOdCor, and N6 > C5 > C8 > C2 of HOdCor. The results suggest that Cordycepin is more easily converted to OXOdCor and HOdCor than canonical adenine nucleosides. Much like typical drugs, after its administration and release, Cordycepin is exposed to various physiological factors and can be exposed to ionisation radiation during combined therapy. These factors can influence the therapeutic potential of Cordycepin. Therefore, further studies on its stability are of utmost importance.

5-(4-bromophenyl)-4,6-dichloropyrimidine was arylated with several aryl/heteroaryl boronic acids via the Suzuki cross-coupling reaction by using Pd(0) catalyst to yield novel pyrimidine analogs (3a-h). It was optimized so that good yields were obtained when 5 mol % Pd(PPh3)4 was used along with K3PO4 and 1,4-Dioxane. Electron-rich boronic acids were succeeded to produce good yields of products. Density functional theory (DFT) calculations were also applied on these new compounds to analyze their reactivity descriptors and electronic and structural relationship. According to DFT studies, compound 3f is the most reactive one, while 3g is the most stable one. As per DFT studies, the hyperpolarizability (β) values of these compounds do not show them as very good non-linear optical (NLO) materials. Compound 3f has the highest β value among all the compounds under study but still it is not high enough to render it a potent NLO material.