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Vitamin K is one of the most important fat-soluble vitamins and while there are two main types of vitamin K in nature, known as K1 (phylloquinone) and K2 (menaquinones), there is also a synthetic type of vitamin K known as K3 (menadione). Recent studies have shown that it is crucial to know the non-covalent interactions, ADME and molecular docking of molecules in different solvent media. Therefore, we have performed some quantum chemical calculations, ADME and intra-and intermolecular interaction calculations of a number of K1, K2 and K3 such as K1-water (K1 + W), K1-methanol (K1 + M), K1-triacetin (K1 + T), K2-water (K2 + W), K2-methanol (K2 + M), K2-triacetin (K2 + T), K3-water (K3 + W), K3-methanol (K3 + M), K3-triacetin (K3 + T) performed by Density Functional Theory (DFT) and Multiwfn: A multifunctional wavefunction analyzer. Molecular structures, HOMO-LUMO energies, MEP and electronic properties have been calculated and described using DFT at the level of B3LYP/6-311G (d,p) level. The nature of the molecular interactions between vitamin K and solvents such as water, methanol and triacetin were also investigated using topological analyses such as atoms in molecule (AIM), non-covalent interaction index (NCI), reduced density gradient (RDG), Localized orbital locator (LOL) and electron localization function (ELF). In addition, FMO for electronic transitions, MEP for electrophilic and nucleophilic attack, ADME to investigate how a chemical is processed by a living organism, and Fukui functions to determine electron density are explained. Finally, molecular docking was used to determine the biological activity of the vitamin K., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The stability of gemcitabine anticancer drug on the functionalized (8,0) zigzag carbon nanotube as a drug delivery vehicle is studied within the formalism of the density functional theory calculations to understand the role of the pyrrolidine functional group in binding the adsorbed molecule to the drug delivery system as well as improving water solubility. The binding energies, natural bond orbital calculations, and the quantum theory of atoms in molecules results are obtained to provide more evidences related to the intermolecular interaction between gemcitabine drug and the functionalized nanotube. The negative binding energy corresponds to favorable binding of gemcitabine drug to the functionalized nanotube and presence of the active sites available for hydrogen bond formation facilitates better drug binding to the nanotube sidewall. The results presented in this article indicate that pyrrolidine functionalized carbon nanotube seems to be a novel material for drug delivery applications. Communicated by Heidar Moradnia.

The electronic structure, stability, acidity, topological properties and charge transfer of octahedral magnesium-carboxylate complexes have been investigated at M05-2X/6-311G** level of theory. The interaction energy studies confirm the stability of the pentahydrated magnesium compounds. The calculated pK a values using SMD solvation model through the deprotonation of metal-ion bound water molecule vary from 15.08 to 19.36, enunciate the role of Mg-O bonds on the acidity of the Mg +2 complexes. The closed shell ionic interactions of Mg-ligand bonds are assessed by the atoms in molecules (AIM) and the electron localization function (ELF) analyses. A reduced density gradient approach is utilized to explore the weak interactions including dihydrogen bonds., (Copyright © 2018 Elsevier Inc. All rights reserved.)

In the present work, we apply comprehensive theoretical calculations in order to study Tegafur drug adsorption on the nanostructured functionalized Graphene with hydroxyl, epoxide, carbonyl, and carboxyl groups in the water environment. The physical nature of Tegafur adsorption offers advantages in terms of easy desorption of anticancer molecule with no structural or electronic change of the adsorbed drug. By functionalization of Graphene nanosheet with a carbonyl group, a considerable increase on the binding energy between Tegafur drug and the nanosheet is noted. Diminish in energy gap with the adsorption of Tegafur drug on the functionalized nanosheets shows that the reactivity of functionalized complexes increases upon loading of the drug molecule. Besides, the adsorption process yields an increase of the polarity which causes the possibility of the solubility and dispersion of the considered complexes enhances. This result is indicative the suitability of the nanomaterials toward Tegafur drug delivery within the biological environments. The high solvation energy of Tegafur anticancer drug adsorbed functionalized Graphene models enforced their applicability as nanocarriers in the living system. These results are extremely relevant that the chemical modification of Graphene nanosheet using covalent functionalization scheme is an effectual approach for loading and delivery of Tegafur drug molecule within biological systems.

Abstract\nHIGHLIGHTSThis paper describes the synthesis, spectroscopic characterization, in-vitro activity on A549 cell line, density functional theory, structure-activity relationship, molecular docking and ADMET evaluation of 2H-pyrido[1,2-a] pyrimidine-2,4(3H)-dione (PY) and 4-hydroxy-1,8-naphthyridin-2(1H)-one (NI). It was discovered that PY and NI showed moderate cytotoxicity against A549 cell line. Both the compounds PY and NI shows a remarkable decrease in the % cell viability of approx. 23% and 22% respectively. The ADMET analysis predicted a stronger effect for the P-glycoprotein activity. The first hyperpolarizabilities (β0) were found to be 2.21*10−30 esu (PY) and 5.79*10−30 esu (NI) respectively and compared with the standard reference urea. It was observed that the chemical reactivity of NI was better as compared to PY and ultimately it may be regarded as a good synthetic intermediate for the synthesis of a number of bioactive heterocycles like Vosaroxin, Gemifloxacin, quinazolines and many more.The two isomeric pyridine derivatives (PY and NI) were synthesized.In-silico studies of PY and NI include DFT, Molecular dynamics, ADMET, etc.The experimental values of PY and NI were in agreement with the theoretical results.PY and NI were investigated on the basis of ADMET and docking score and compared with Gilotrif.Compound NI was found most potent against the cancer cell line (A549).The two isomeric pyridine derivatives (PY and NI) were synthesized.In-silico studies of PY and NI include DFT, Molecular dynamics, ADMET, etc.The experimental values of PY and NI were in agreement with the theoretical results.PY and NI were investigated on the basis of ADMET and docking score and compared with Gilotrif.Compound NI was found most potent against the cancer cell line (A549). [ABSTRACT FROM AUTHOR]

Context: The 2,4-dioxo-4-phenylbutanoic acid (DPBA) is a subject of interest in pharmaceutical research, particularly in developing new drugs targeting viral and bacterial infections. Complexation with metal ions can improve the stability and solubility of organic compounds. The present study uses quantum chemical calculations to explore the structural and electronic results arising from the interaction between the metal cation (Fe2+) and the π-system of DPBA in different solvents. For this purpose, the analyses of atoms in molecules (AIM) and natural bond orbital (NBO) are employed to comprehend the interaction features and the charge delocalization during the process of complexation. The results demonstrate that the strongest/weakest interactions are evident when the complex is situated in non-polar/polar solvents, respectively. In addition, the investigated complex exhibits two intramolecular hydrogen bonds (IMHBs) characterized by the O–H···O motif. The results indicate that the HBs present in the complex fall within the category of weak to medium HBs. Moreover, the O–H···O HBs are influenced by cation–π interactions, which can increase/decrease their strength in polar/non-polar solvents. To enhance understanding of the interactions above, an examination is conducted on various physical properties including the energy gap, electronic chemical potential, chemical hardness, softness, and electrophilicity power. Method: All calculations are conducted within the density functional theory (DFT) using the ωB97XD functional and 6–311 + + G(d,p) basis set. The computations are performed using the quantum chemistry package GAMESS, and the obtained results are visualized by employing the GaussView program. [ABSTRACT FROM AUTHOR]

Piperazin-1-ium 4-aminobenzoate monohydrate (PPAB) single crystals were grown by slow evaporation method. The grown crystal PPAB has been characterized by single-crystal X-ray diffraction, FTIR, FT-Raman, and UV-visible analysis. The B3LYP method and 6-311G (d, p) basis set were used to optimize the structure. The title compound was investigated theoretically and experimentally by FT-IR, FT-Raman, and UV-Vis spectral analysis. The presence of various functional groups in the structure was elucidated by FTIR and FT-Raman spectral studies. The intermolecular interactions within the crystal structure were investigated using Hirshfeld surface analysis. The crystal packing diagram reveals interesting non-covalent interactions involving C–H···O, N–H···O, and N–H···N hydrogen bonds, leading to the generation of 3D supramolecular architecture. The charge transfer within the molecule was deeply analyzed by using the NBO approach. The molecular electrostatic potential (MEP) and the local reactivity descriptors, such as Fukui function (fk+, fk−) analyses were performed to determine the reactive sites within the molecule. The HOMO and LUMO analysis was used to determine the chemical reactivity and bioactivity of the molecule. Hole-electron analysis was performed to analyze the charge transfer in an excited state. Based on the hole-electron analysis, the inter-fragment charge transfer (IFCT) analysis establishes the amount of charge transfer among different fragments. Topological analyses, such as AIM, RDG, and ELF were carried out to identify the non-covalent interaction within the molecule. The molecular docking studies of the molecule are performed to investigate the binding affinity of the ligand with the protein receptor. Drug-likeness properties, such as Lipinski's rule of five, adsorption, distribution, metabolism, excretion, and toxicity (ADMET) have been investigated by in silico web-based tools like SwissADME and ADMETlab. [ABSTRACT FROM AUTHOR]

The structural, vibrational, electronic, and nonlinear optical properties of 4-amino benzoic acid pyrazinoic acid were obtained using spectral methods and density functional theory calculation. The title compound was characterized by Fourier transform infrared, Fourier transform-Raman, UV-Vis spectral studies and single crystal x-ray diffraction technique. By using density functional theory (DFT) using B3LYP method with 6-31 G(d,p) basis sets. The molecular geometry and vibrational frequencies were calculated and compared with the experimental data. The intermolecular contact of title compound was studied by Hirshfeld surface analysis whereas an intra-molecular hydrogen bonding interaction was examined through reduced density gradient plot. Molecular electrostatic potential and Fukui functions were also performed. Wave functional study like electron localization functions were analyzed. Bader's theory of atoms-in-molecule conjointly with natural bond orbital have been analyzed. The natural bond orbital (NBO) analysis enabled in comprehending the stability and charge delocalization in the title molecule. The first hyperpolarizability which is an important parameter for future studies of nonlinear optics (NLO) was calculated to check the potential of the molecule to be an NLO material. [ABSTRACT FROM AUTHOR]

Using density functional theory, polyols were used as model ligands for Cu+/Cu2+ complexes to study the role of the hydrogen bond network on the metal binding affinity. In addition to the gas phase studies, the calculations were performed in 1‐decanol and DMSO solvents. The Cu2+ complexes were the most stable complexes with the highest bond dissociation energies (BDE). The presence of three H‐bonds in the first shell increased BDE values up to 17.99 and 57.07 kcal/mol for Cu+ and Cu2+ complexes in the gas phase, respectively, whereas the presence of another three H‐bonds in the second shell increased BDE values up to 7.27 and 24.35 kcal/mol for Cu+ and Cu2+ complexes in the gas phase, respectively. Therefore, this H‐bond network caused, for example, a more stable Cu+ complex with a formation constant of 1.4 × 1017 times. The natural bond orbital (NBO), atoms in molecules (AIM), and reduced density gradient (RDG) analyses showed that the intramolecular hydrogen bond network led to the enhancement of metal‐binding affinity. [ABSTRACT FROM AUTHOR]

The motivation of this study is to investigate the interaction of Si12C12, BSi11C12, NSi11C12, BSi12C11 and NSi12C11 nanocages with Glycine amino acid (Gly). The density functional theory (DFT) and time-dependent density functional theory (TD-DFT) at the cam-B3LYP/6-31G (p, d) level of theory by using Gaussian 09 software are utilized for this aim. The calculated results illuminate that the interaction of Gly with Si12C12, BSi11C12, NSi11C12, BSi12C11 and NSi12C11 nanocages is exothermic, and favorable in thermodynamic view. The adsorption of Gly from oxygen site (C=O) with NSi11C12 and BSi12C11 nanocage is more favorable than other complexes. The natural bonding orbital (NBO) results depicted that the electron charge transfer occur from Gly molecule toward SiC nanocage. The atom in molecule (AIM) and reduced density gradient (RDG) results confirm that the bonding between Gly and SiC nanocage is partially covalent or electrostatic type. The gap energy and global hardness of all studied complexes are lower than pure state, so the conductivity and reactivity of these complexes are more. The results of this study demonstrate that the Gly strong interact with BSi11C12, NSi11C12, BSi12C11 and NSi12C11 nanocages and the electrical structures of Gly alter significantly from pure state. These results can be considered in biological systems to investigate the effect of SiC nanocage in drug carriers and also provide information about the interaction of this nanocage with proteins in the body. [ABSTRACT FROM AUTHOR]

In this work, we have investigated the complex formation capability of gemcitabine drug with host cucurbit[n]urils, Q[n] (n = 6, 7, and 8) using density functional theory (DFT). The DFT studies demonstrate that the most stable configuration is a fully encapsulated complex. In the encapsulated gemcitabine@Q[6] and gemcitabine@Q[7] complexes, the gemcitabine amino -NH2 and the alcoholic groups bond with the carbonyl units of Q[n]. The addition of sodium ions leads to the partial exclusion of the gemcitabine molecule and the sodium atoms lie close to the carbonyl portal of Q[7]. Thermodynamic parameters computed for the complexation process exhibit high negative Gibbs free energy change, implying that the encapsulation process is spontaneous and is an enthalpy-driven process. Frontier molecular orbitals are located mainly on the gemcitabine uracil ring, before and after encapsulation, indicating that the encapsulation occurs by pure physical adsorption. Quantitative molecular electrostatic potentials demonstrate a shift in electron density during the complex formation and are more pronounced in gemcitabine@Q[7]. Atoms-in-molecule (AIM) topological analysis illustrate that these complexes are stabilized by various non-covalent interactions including hydrogen bonding (HBs) and C···F interactions. The reduced density gradient (RDG) graph exhibits the presence of strong HBs and weak van der Waals interactions and the presence of steric repulsion. The isosurface non-covalent interactions (NCI) diagram shows predominant steric interaction in the gemcitabine@Q[6] complex. The NCI isosurface for gemcitabine encapsulated complexes with Q[7] and Q[8] host displays that the green patches are uniformly distributed in all directions. Finally, EDA results demonstrate Pauling's repulsive energy is predominant in gemcitabine@Q[6] complex, while the orbital and dispersion energies stabilize the gemcitabine@Q[7] complex. [ABSTRACT FROM AUTHOR]

The density functional theory and vibrational spectroscopy investigation were carried out on 6-Fluoro-4-oxo-3,4-dihydro-2H-chromene-2-carboxylic acid (FODHCC). The optimized structure, vibrational frequencies, and other chemical parameters are obtained using the B3LYP method with a 6-311++G(d,p) basis set. FT-IR studies are used to identify the various functional groups, which are then compared with simulated spectra. Atoms In Molecules (AIM) studies are carried out to know the bonding nature. NBO analysis is used to investigate the interactions between donors and acceptors. The stability, hardness, and softness are studied by Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO). The molecular electrostatic potential (MEP) is used to determine the molecule's reactive regions. The maximum absorption wavelength is determined using the UV-Vis spectrum and compared with the simulated spectrum created using TD-DFT/CAM technique with various solvents. The NLO studies were carried out on the molecule to know the dipole moment and other NLO parameters. The molecule is utilized in biological studies such as molecular docking and drug similarity. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) and the Møller–Plesset expansion (MP2) calculations were benchmarked to characterize the structure of novel derivatives of carbene hydroxymethylene. In this regard, eleven numbers of primary aldehydes including formaldehyde, acetaldehyde, formyl chloride, 2-chloroacetaldehyde, formyl fluoride, 2-fluoroacetaldehyde, formic acid, propionaldehyde, glyoxal, methyl formate, and formyl bromide (1H–11Br) were scrutinized, at the B3LYP/6-311++G(3d,3p) level of theory. Thereafter, the process of keto-enol tautomerism via a [1,2]-H-shift of 1H–11Br was monitored to reach their corresponding enol forms (1P–11P). For all species (except for one structure), the TS involves a triangle structure of C–O–H and yields cis or trans isomers of a singlet ground-state (S) carbene that contrasts the multiplicity of ordinary carbenes. The bond dissociation energy (BDE) calculations were carried out for the homolytic cleavage of C–H bonds of 1H–11Br. The AIM, as a promising analysis that definitely reveals the nature of the bond, was conducted to characterize the eigenvalues at the bond critical points (BCPs). In addition, the relation between the Hammett equation and thermodynamic parameters was obtained. Our investigation suggests new stable S derivatives of carbene hydroxymethylene that can be isolated. [ABSTRACT FROM AUTHOR]

In this study, 4-(5-methyl-[1,2,4]triazolo[1,5-a]pyrimidine-7-yloxy) phthalonitrile (coded as MTPPN) was chosen as the phthalonitrile compound and the quantum chemical and in-silico studies have been done. First, the basis set of the time dependent density functional theory (TD-DFT) method was used and the boundary orbital energies and band gap calculations of the molecule were performed. Analysis of atoms in molecules (AIM) theoretical calculations is presented to learn about electron density and bond critical point. In addition, absorption, distribution, metabolism, and excretion analyzes (ADME) were performed for the drug potential of the compound. On some enzymes effect of MTPPN compound was examined. The docking score was obtained for AChE, BChE, α-GLY proteins -7.864, -6.848, and -5.511 kcal/mol, respectively. MTPPN gave a good inhibitory performance in an in-silico study as a drug candidate. [ABSTRACT FROM AUTHOR]

Gallic acid is the major constituent in fruits Phyllanthusemblica (amla), of the family phyllanthaceae. Gallic acid was first methylated to 3,4,5 trimethoxygallic acid, which upon esterification using steglich method with cholesterol resulted in the product (3S,8S,10R,13R,17R)-10,13-dimethyl-17-((R)-6-methylheptan-2-yl)-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-3-yl 3,4,5-trimethoxybenzoate. The synthesized compound has been characterized by ¹H NMR, 13C NMR, UV, FT-IR and mass spectroscopy. Density functional theory (B3YLP) using a 6-31G (d,p) basis set has been used for quantum chemical calculations. The reactive site and reactivity within the molecule are rendered by global and local reactivity descriptors, whereas AIM (Atom in a molecule) approach illustrated weak molecular interactions within the molecule. The energies of HOMO and LUMO and frontier orbital energy gap are calculated by time dependent DFT approach using the IEFPCM model. A small value for the HOMO-LUMO energy gap indicates easier charge transfer within the synthesized compound. The nucleophilic and electrophilic reactivity is determined by MEP (molecular electrostatic potential) studies. The values calculated for polarizability, dipole moment, and first hyperpolarizability are used to depict the NLO (nonlinear optical) property of the synthesized compound. [ABSTRACT FROM AUTHOR]

• Investigated SA-drug interactions with C 24 , H+C 24 , and 2H+C 24 nanocages. • B-a and C-b models showed the smallest SA-drug and C 24 distance, with high adsorption. • C-b model favored for adsorption on 2H+C 24 with most negative E ads and ∆G. • Bonding interactions mainly van der Waals and hydrogen bonding, enhancing optics. • NLO and UV–visible spectra showed significant optical property improvements. In the realm of drug design, achieving precise and effective drug delivery poses a significant challenge. In this computational study, we explore the capacity of pristine C 24 nanocages and those modified with 1H+ and 2H+ ions to serve as carriers for the sulfacetamide (SA) drug, employing density functional theory (DFT) calculations. Geometry optimizations of the SA&C 24 , SA&H+C 24 , and SA&2H+C 24 complexes were conducted at the cam-B3LYP/6–31+ G (d, p) level of theory. The optimized structures of all complexes exhibit local minima on the potential energy surface, indicated by the absence of imaginary frequencies, which confirms their thermodynamic stability. The negative values of adsorption energy (E ads) denote an exothermic and favorable adsorption process, with H + ion functionalization enhancing the drug's binding affinity to the nanocages. Further analysis of the structural properties of the complexes was conducted through natural bond orbital (NBO) charge distribution, dipole moment calculations, and frontier molecular orbital analysis. Additionally, Atoms in Molecules (AIM), reduced density gradient (RDG), and electron localization function (ELF) analyses were employed to elucidate the nature of intermolecular interactions governing the drug-nanocage binding. UV-visible and nonlinear optical (NLO) response calculations reveal the potential of both pristine and functionalized C 24 nanocages as optical sensors for SA drug detection. Our findings suggest that these nanocages hold promise for the development of sensitive drug delivery vehicles and targeted therapeutic agents. [ABSTRACT FROM AUTHOR]

A detailed study on mesalazine⋯Fe2+ complex is performed using density functional theory calculations to show the interplay effects of cation–π and intramolecular hydrogen bond (IMHB) interactions in the presence of the different solvents. To achieve better insight on the mentioned interactions, the complex of benzene and the mesalazine analogue is chosen as a set of reference points. For this purpose, the analyses of atoms in molecules and natural bond orbital are applied to study the nature of the bonding. The results exhibit that the coexistence of IMHB and cation–π interactions decreases the IMHB strength and increases the cation–π interactions. The electronic properties, stability and reactivity of the studied complex in the various solvents are also evaluated by frontier molecular orbitals, chemical hardness as well as electronic chemical potential. [ABSTRACT FROM AUTHOR]

Quantum chemical density functional theory (DFT) calculations were performed to investigate the adsorption of arsine (AsH3) gaseous substance at the surface of representative models of boron nitride (B16N16), aluminum nitride (Al16N16), and silicon carbide (Si16C16) fullerene-like nanocages. The results indicated that the adsorption processes of AsH3 could be taken place by each of B16N16, Al16N16, and Si16C16 nanocages. Moreover, the electronic molecular orbital properties indicated that the electrical conductivity of nanocages were changed after the adsorption processes enabling them to be used for sensor applications. To analyze the strength of interacting models, the quantum theory of atoms in molecules (QTAIM) was employed. As a typical achievement of this work, it could be mentioned that the investigated Si16C16 fullerene-like nanocage could work as a suitable adsorbent for the AsH3 gaseous substance proposing gas-sensor role for the Si16C16 fullerene-like nanocage. [ABSTRACT FROM AUTHOR]

The intra- and intermolecular interactions of selected quinolone carboxylic acid derivatives were studied in monomers, dimers and crystals. The investigated compounds are well-recognized as medicines or as bases for further studies in drug design. We employed density functional theory (DFT) in its classical formulation to develop gas-phase and solvent reaction field (PCM) models describing geometric, energetic and electronic structure parameters for monomers and dimers. The electronic structure was investigated based on the atoms in molecules (AIM) and natural bond orbital (NBO) theories. Special attention was devoted to the intramolecular hydrogen bonds (HB) present in the investigated compounds. The characterization of energy components was performed using symmetry-adapted perturbation theory (SAPT). Finally, the time-evolution methods of Car–Parrinello molecular dynamics (CPMD) and path integral molecular dynamics (PIMD) were employed to describe the hydrogen bond dynamics as well as the spectroscopic signatures. The vibrational features of the O-H stretching were studied using Fourier transformation of the autocorrelation function of atomic velocity. The inclusion of quantum nuclear effects provided an accurate depiction of the bridged proton delocalization. The CPMD and PIMD simulations were carried out in the gas and crystalline phases. It was found that the polar environment enhances the strength of the intramolecular hydrogen bonds. The SAPT analysis revealed that the dispersive forces are decisive factors in the intermolecular interactions. In the electronic ground state, the proton-transfer phenomena are not favourable. The CPMD results showed generally that the bridged proton is localized at the donor side, with possible proton-sharing events in the solid-phase simulation of stronger hydrogen bridges. However, the PIMD enabled the quantitative estimation of the quantum effects inclusion—the proton position was moved towards the bridge midpoint, but no qualitative changes were detected. It was found that the interatomic distance between the donor and acceptor atoms was shortened and that the bridged proton was strongly delocalized. [ABSTRACT FROM AUTHOR]

Investigation of complexes of nanostructured materials and biomolecules has attracted much attention by various researchers as it can contribute to coherent growth and extended application of nanostructures in different technologies. In this research, following a comprehensive approach, we examined the interaction between different amino acids and metal–organic frameworks (MOFs) at atomic scale using computational chemistry. For this purpose, we employed the density functional theory (DFT-D2) calculations to afford a molecular description of the interaction properties of the amino acids and MOF-5 by examining the interaction energy and the electronic structure of the amino acid/MOF complexes. We found strong interactions between the amino acids and MOF through their polar groups as well as aromatic rings in the gas phase. However, our findings were significantly different in solvent media, where water molecules prevent the amino acids from approaching the active sites of MOF, causing weak attractions between them. The evaluation of nature of interaction between the amino acids and MOF by the atoms-in-molecules (AIM) theory shows that the electrostatic attractions are the main force contributing to bond formation between the interacting entities. Furthermore, our DFT-PBE model of theory was validated against the comprehensive MP2 quantum level of theory. [ABSTRACT FROM AUTHOR]

In this paper, the substitution effects of titanium heteroatom(s) on aromaticity, the average isotropic polarizability (< α >), the atomic polar tensor (APT) charge, the electrostatic potential (ESP) map, and the atoms in molecule (AIM) analysis along with infrared (IR) spectroscopy of C20 fullerene and its C20-nTin derivatives (n = 1–5) are probed via density functional theory (DFT). The nucleus-independent chemical shifts (NICS) specify that substitution effect causes more aromaticity character of the optimized heterofullerenes than benzene molecule and higher APT charge distribution upon surfaces of them than pure cage. The highest negative and positive APT charge distribution on carbons of C15Ti5 and titanium substitutions of C16Ti4-2 implies that these sites can be attacked more readily by electrophilic and nucleophilic regents, respectively. We are very pleased to state that isolating the Ti–Ti single bonds by intermediacy of one or two C atoms is an applicable strategy for attaining the highest APT charge distribution on Ti atoms of C16Ti4-2 as suitable hydrogen storage. AIM analysis of the studied C20-nAln derivatives signifies the highest electron density (ρ (r)) of 0.294 a.u. and the highest positive Laplacian of electron density (∇2ρ (r)) of 0.190 a.u., at bond critical points (BCPs) of C–Ti bond in the most stable C19Ti1 species. This heterofullerene shows the lowest < α > between the studied structures. IR spectroscopy shows that exclusive of C16Ti4-1 (as transition state), the other optimized hollow cages (as global minima) have no imaginary frequency. [ABSTRACT FROM AUTHOR]

• Compound is analyzed by quantum computational method (DFT) and spectroscopic methods. • NBO analysis and topological studies(AIM,NCI,ELF,LOL) are conducted. • Electron excitation studies are done by analyzing HOMO-LUMO and electron-hole excitation. • Experimental UV-visible spectrum with Tauc's plot satisfied the theoretical energy gap. • Molecular docking, drug likeness and ADMET of the molecule discussed. This study presents a comprehensive investigation into Prednisolone, a glucocorticosteroid drug, through vibrational analysis and DFT based quantum chemical calculations. Utilizing the DFT-B3LYP functional at the basis set 6-311++G(d,p), the research explores conformational and geometric aspects, harmonic vibrational wavenumbers, and FMO analysis. The phase angle of pseudo rotation is measured to predict the molecule's conformation. FT-IR and Raman spectra were analyzed and found that the lowering of symmetric stretching vibrations of O25-H53 and O24-H52 to 3470 and 3362 cm−1 respectively, is due to the presence of intra/intermolecular hydrogen bonding. Topology analysis (AIM, NCI,ELF, LOL) global chemical reactivity descriptor study, Hirshfeld surface analysis and electron excitation studies provide a detailed understanding of Prednisolone's molecular properties. AIM analysis proved the possibility of a strong hydrogen bond H53.......O24, because it has the minimum bond length of 1.9645 Å, accompanied by a maximum ρ value of 0.0255 a.u. The hydrogen bond O24.......H53 —– O25, indicated by blue RDG isosurfaces in NCI, with value of sign (λ2) ρ between -0.02 to -0.05 a.u, is predicted to be strong. Bandgap energy of the molecule calculated from HOMO-LUMO is 4.7105. This is well agreement with the results obtained from experimental UV-visible spectra. Molecular docking study, Drug likeness parameter analysis and ADMET properties helps in predicting the anti-inflammatory activity of the molecule. [Display omitted] [ABSTRACT FROM AUTHOR]

This study thoroughly investigated the potential of using 3,3-dimethyl-2,6-di- p -tolylpiperidin-4-one, (DMeTP) as an anti-Parkinson medicine against Parkinson's disease. To accomplish this, DMeTP was synthesized and characterized by various spectral techniques such as FT-IR, NMR, and Mass. The Hirshfeld analysis and finger plot were used in this study to reveal important insights about the intermolecular relations of the compounds. The theoretical analyses of the compound was carried out using Density Functional Theory (DFT) at the level of theory B3LYP/6–311++G (**). The frontier orbital and the molecular electrostatic potential studies proved the chemical stability of the DMeTP structure. Then, weak interactions like hydrogen and Vdw interactions were investigated throughout the topological study (AIM and RDG). The alpha-synuclein protein was used in a molecular docking analysis to uncover inhibitory properties against Parkinson's disease. Additionally, the pharmacokinetic and physicochemical characteristics of the DMeTP molecule were examined using the SwissADME online program. [Display omitted] • DMeTP compound synthesized and characterized by FT-IR, 1H NMR, 13C NMR, Mass spectra, and X-ray crystallography analysis. • Optimized structure was done DFT/ B3LYP/6-311++G (**) level of theory. • Hirshfeld surface analysis of the DMeTP compound has been reported. • Molecular docking analysis of DMeTP shows potent activity against Parkinson's disease. • Pharmacokinetics and physicochemical characteristics of the DMeTP molecule were reported. [ABSTRACT FROM AUTHOR]

Density functional theory method and B3LYP/6‐311++G(d,p) level of theory were used to determine the acidity of α‐carbon in the hydroxyl derivatives of beta diketones in the gas phase. An investigation of acidity strength in the gas phase indicates that α‐carbon of hydroxyl derivatives of beta diketones become stronger acids than the α‐carbon of beta diketone itself as their conjugate bases gain more stability via both enolate and hydrogen bond formation. Natural bond orbital and quantum theory of atoms in molecules analyses also confirm the role of hydrogen bond interactions on increasing the acidity of α‐carbon of hydroxyl derivatives of beta diketones. [ABSTRACT FROM AUTHOR]

In this study, the density functional theory computational method is used to investigate the encapsulation process of metformin into three types of the cyclic peptides composed of eight serine (CP1), eight glycine (CP2), and four serine‐glycine (CP3) cyclic peptides as a new model in the process of drug delivery in the gas phase. The obtained results using the B3LYP/6‐31++G (d,p) method indicate that the complexes formed are energetically favored. Furthermore, results reveal that the drug encapsulation process is typically chemisorption. The natural bonding orbital analysis shows that the intermolecular interaction of the C2 complex (metformin/CP2) is stronger than the C1 (Metformin/CP1) and C3 (Metformin/CP3) complexes due to greater total charge transfer energy, and the C1 complex is found to be the most favored complex. The theory of atoms in molecule (AIM) method is used to analyze the nature of interactions in different molecular systems. The results show the investigated cyclic peptides as effective carriers of metformin in the nanomedicine field. [ABSTRACT FROM AUTHOR]

It was studied some physical and chemical properties of 2,4-dihydroxy quinoline derivative diazo dyes by theoretical methods. Six different solvents were used to determine the solvatochromic behavior and absorption of the compounds, and the experimental results were compared with the theoretical data obtained from quantum chemical calculations. DFT calculations were carried out to obtain the geometric, electronic and some chemical reactivity parameters of the compounds. The atom in molecule, natural bond orbital, density of state, noncovalent interaction, Fukui function, electron localization function, and electron delocalization range analyzes of the compounds were performed to determine the relationship between the electronic properties and the DNA binding capacity and the cytotoxicity against HeLa and PC3 cancer cell lines. It was observed that the compounds substituted with -Cl and -NO2 had higher DNA binding and higher anticancer effect. Besides the positions of the substituents, the electron density in the bonds, the delocalization index values and the distribution of the nucleophilic and electrophilic attack sites are among the important factors determining the reactivity of the compounds. In addition, the HOMO energies of the compounds with better DNA binding properties were calculated higher than the other compounds. [ABSTRACT FROM AUTHOR]

Herein, (E)-4-{[(2-amino-5-chlorophenyl)imino]methyl}-5-(hydroxymethyl)- 2-methylpyridin-3-ol [HL] Schiff base and its [Cu(L)Cl] complex were newly synthesized and characterized by several spectroscopic methods. In addition, density functional theory (DFT) methods were used for investigation of the tautomerization of the HL Schiff base, structural parameters of HL and [Cu(L)Cl] species, assignment of the IR vibrational bands and the NMR chemical shifts as well as natural bond orbital (NBO) analyses. The most stable tautomer of the HL Schiff base is the enol form of the meta isomer. The optimized geometry of the free HL Schiff base is not planar. The L- acts as a N2O tridentate ligand, which is bonded to Cu2+ via the deprotonated phenolic oxygen, and the amine and azomethine nitrogens. The [Cu(L)Cl] has a square planar geometry in which the chloro ligand occupies the fourth coordination position. The DFT-computed values are in good consistency with the corresponding experimental values, confirming the suitability of the optimized geometries for HL and [Cu(L)Cl] species. According to the high-energy gaps, these compounds are stable. The atoms in molecule (AIM) analysis was used to evaluate strength of the bonding interactions and electron densities in structure of the compounds. [ABSTRACT FROM AUTHOR]

The present work utilizes density functional theory (DFT) calculations to study the influence of cation–π interactions on the electronic properties of the complexes formed by Altretamine [2,4,6‐tris(dimethylamino)‐1,3,5‐triazine], an anticancer drug, with mono‐ and divalent (Li+, Na+, K+, Be2+, Mg2+ and Ca2+) metal cations. The structures were optimized with the M06‐2X method and the 6‐311++G(d,p) basis set in the gas phase and in solution. The theory of 'Atoms in Molecules' (AIM) was applied to study the nature of the interactions by calculating the electron density ρ(r) and its Laplacian at the bond critical points. The charge‐transfer process during complexation was evaluated using natural bond orbital (NBO) analysis. The results of DFT calculations demonstrate that the strongest/weakest interactions belong to Be2+/K+ complexes. There are good correlations between the achieved densities and the amounts of charge transfer with the interaction energies. Finally, the stability and reactivity of the cation–π interactions can be determined by quantum chemical computation based on the molecular orbital (MO) theory. [ABSTRACT FROM AUTHOR]

Density functional theory calculations were performed to explore four octahedral energetic complexes including [CoCl2 (ANQ)2], [Co (ANQ)2(H2O)2]2+, [CuCl2 (ANQ)2], and [Cu(NO3)2 (ANQ)2], (ANQ = amino nitroguanidine). In this work, an attempt has been made to present useful structural data in order to investigate and predict the explosive properties of these complexes. In this regard, interaction energy (IE), natural bond orbital (NBO), atoms in a molecule (AIM) as well as the three-dimensional Hirshfeld surface analysis and the two-dimensional fingerprint plots, charge transfers, HUMO-LUMO gap, oxygen balance (%OB) amounts, and molecular electrostatic potential (MEP) maps were utilized to assign intermolecular interactions, bond lengths, the nature of metal-ligand bonds, and energies in subject compounds. The results reveal that among the five applied levels of theory, interaction energies obtaining from M06-2X/Def2TZVP were in excellent compliance with the experiments. Additionally, the N⋯O interaction, oxygen balance, density, and HOMO–LUMO gap were the most contributing factors in assigning sensitivity and detonation properties. In general, the sensitivity and detonation properties are increased in the following order: ANQ < complex1 < complex3 < complex2 < complex4. [ABSTRACT FROM AUTHOR]

• diaqua-bis(indazole-κN2)bis(nitrato-κO)zinc(II) complex was synthesized and characterized. • Intermolecular interactions were explored using Hirshfeld surface analysis and AIM, NCI-RDG approach. • DFT calculations were compatible with experimental findings. • Important findings on the complex properties were obtained using MEP, NBO and FMO analyses In this study, the diaqua-bis(indazole-κN2)bis(nitrato-κO)zinc(II) complex has been examined by using single-crystal X-ray diffraction (XRD) and spectroscopic analysis methods (FT-IR, UV-Vis). The Zn(II) ion is hexa-coordinated, and the coordination environment around Zn(II) is best considered as a slightly distorted octahedral geometry. The theoretical calculations were carried out using the density functional theory (DFT) method. Hydrogen bonding in particular has been assessed through topological analysis using methods like electron localization function (ELF), localized orbital locator (LOL), natural bond orbital analysis (NBO), and the atoms in molecules method (AIM). Also, the reduced density gradient approach (RDG) has been used to determine the strong and weak attractive, repulsive, and van der Waals interactions in the title complex. The Hirsfeld surface analysis was used to investigate the nature of the crystal structure's intermolecular interactions. The reactivity of the complex was investigated through the use of MEP and HOMO-LUMO studies. The molar conductivity values of the compounds provided evidence of their non-electrolytic nature, while thermal data indicated that the complexes decompose into metal oxide residue in five stages. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Interaction of amiloride with (Be/Ca-O) 12 and Ag doped nanocages. • High adsorption energy of −36.98 eV in CaO nanocage. • Enhancement of different modes in the AM-nanocage's Raman spectra. • Steric effect is brilliantly reddened in CaOAg-AM. Amiloride is a drug used in the management and treatment of hypertension and heart failure and in the present work, the interaction of amiloride (AM) with (Be/Ca-O) 12 and Ag doped nanocages were studied, based on the density functional theory (DFT) in a B3LYP/def2-TZVPPD level of theory. The drug's adsorption was confirmed by the measurement of the adsorption energy of AM on the BeO, CaO, BeOAg and CaOAg surface, which were found to be around −6.05, −36.98, −13.11 and −8.79 eV respectively. There is an enhancement of different modes in the AM-nanocage's Raman spectra in comparison with that of pristine AM. In CaOAg-AM, the steric effect is brilliantly reddened by the ring of aromatics' center. The present work can be extended to investigate the effect of other various types of nanorings and nanocages to study doping effects and drug delivery carrier properties. [ABSTRACT FROM AUTHOR]

Two vanadyl complexes of the pyridoxal Schiff bases have been newly synthesized and characterized by several experimental methods, where the 4,4'-[1,4-butanediylbis-[(E)-nitrilomethylidyne])bis[5-hydroxy-6-methyl- -3-pyridinemethanol] and trans-4,4'-[1,2-cyclohexanediylbis-[(E)-nitrilo-methylidyne]] bis[5-hydroxy-6-methyl-3-pyridinemethanol] Schiff base were used. Geometry optimization, assignment of the IR vibrational frequencies and the natural bond orbital (NBO) analysis of the complexes have been calculated by employing the density functional theory (DFT) approaches. Deprotonated form of the Schiff bases (L2-) acts as a tetradentate N2O2 ligand, which coordinates to the V(IV) via two phenolate oxygens and two imine nitrogens. In the square-pyramidal geometry of the [VO(L)], the apical position is occupied by an oxo ligand. The DFT-calculated vibrational frequencies show a good consistency with the corresponding experimental values, confirming suitability of the optimized geometries for the complexes. Characteristics of the bonding interactions have been explored using the quantum theory of atoms in molecule (QTAIM) analysis. The complex formation results in decrease in strength of the C-N bond of the azomethine group and increase in the strength of the C-O bonds of the phenolate group. High-energy gaps approve stability of the complexes. Both of the complexes show significant radical scavenging activities against the ABTS and DPPH radicals, even higher than the BHA. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) calculations at B3LYP/6-31+G(d) level were employed to investigate the influence of the non-metal encapsulation of the second row of the periodic table of elements on the optoelectronic response properties. Besides, the adsorption of amphetamine (AMP) on the surface of B12N12 nano-cage quantum theory of atoms in molecules (QTAIM) was employed to analyze the topology of electron density and bonding properties of the studied systems. It is demonstrated that the energy gap of the encapsulated nano-cages reduces significantly as compared to pristine B12N12 leading to an increase in the electrical conductance of the nano-cage. Aside from that, encapsulation drastically enhances the interaction of AMP with B12N12 nano-cage. Among non-metals of the second row of the periodic table, fluorine has the highest influence on the adsorption energy of the AMP and also on the surface of B12N12 nano-cage. However, carbon in triplet-state encapsulation greatly enhances the sensitivity of the B12N12 nano-cage to AMP. Finally, QTAIM results indicated that encapsulation increases the covalent character of N–B bonding. [ABSTRACT FROM AUTHOR]

Interaction of small neutral coinage metal clusters (M 19 = Ag 19 /Au 19) with thiol/alkoxy radical (E = -SCH 3 , -OCH 3 , and -OCH 2 CH 3) has been investigated to understand the bonding mechanism in the coinage metal−molecule junctions, which would allow to design biocompatible materials. In this study, structure, reactivity, and energy decomposition analysis (EDA) of M 19 −E complexes have been unravelled using density functional theory (DFT) based Perdew, Burke and Ernzerhof (PBE) method. In addition, the theory of "atoms in molecules" (AIM) has also been used characterize the nature of interaction. The calculated reactivity descriptors predict that the vertex atoms (Ag/Au) are the most reactive site for nucleophilic attack. The atoms lying at the center of each face are favourable for an electrophilic attack in both the cases. Geometrical parameters illustrate that the structure of the molecules change significantly before and after interactions. The signatures of ∇2ρ(r) and H c for the anchoring bonds are respectively positive and negative, revealing that these bonds are partially electrostatic and covalent in nature. EDA calculation indicates that the largest contribution to the M−X (X = O/S) bond arise from Δ E orb and Δ E elstat contributions. Specifically, contribution from the orbital interaction is higher than the electrostatic contribution, which further confirms the covalent nature of the interaction. Unlabelled Image • The nucleophilic/electrophilic attacks are feasible at the vertex/atop site. • The atoms lying at the center of M 19 clusters are favourable sites for electrophilic attack. • The strength of M−S bond can induce large deformation leading to the surface reconstruction and eventually pull out a metal atom from the surface. • M-X interaction is partially electrostatic and covalent in nature. [ABSTRACT FROM AUTHOR]

The possible involvement of chemical compounds in atmospheric new particle formation has received increased attention in recent years. Extensive density functional theory calculations were performed to characterize the effects of the inter- and intra-molecular hydrogen bonding interactions in forming atmospheric malonic acid (MOA)-containing clusters. Methanol, water, formaldehyde, and acetone are common atmospheric nucleation precursors, and they were chosen as the counterpart to interact with MOA. There are two types of hydrogen bonds: addition and insertion. When MOA behaves as the donor of a hydrogen bond, the formation of an inter-molecular hydrogen bond lightly increases the strength of the intra-molecular hydrogen bonds. Strong hydrogen bonds were formed when MOA executes as a hydrogen bond donor. The strength of the insertion conformer depends on the inserting molecule. The IR frequencies of the hydrogen bonded system were investigated. Furthermore, geometrically identified inter- and intra-molecular hydrogen bonds were provided by atoms in molecules approach. [ABSTRACT FROM AUTHOR]

A Cu(II) complex of the N,N′-dipyridoxyl(1,2-diaminobenzene) [=H2L] Schiff base is newly synthesized. The complex is characterized experimentally and theoretically. The density functional theory methods are employed to calculate the optimized geometry along with the natural bond orbital analysis and the vibrational frequency analysis of the complex. The computed IR frequencies are in agreement with the experimental one, confirming the validity of the proposed geometry for the complex. In the optimized geometry of the octahedral complex, dianionic L2– acts as a tetradentate ligand. Two azomethine nitrogen atoms and two phenolate oxygen atoms of the L2– ligand occupy four square positions of the complex. Also, two methanol ligands are perpendicular to the square plane. The large energy gap between the frontier orbitals demonstrates the stability of the complex. The properties of the Cu–N and Cu–O bonds are investigated by the Atoms In Molecules analysis, too. [ABSTRACT FROM AUTHOR]

The interactions of ascorbic acid (AA) with urea were investigated by using the cyclic voltammetry, density functional theory, atoms in molecules and natural bond orbital analyses. The experimental and theoretical results show that the hydrogen bonds are formed between AA and urea, wherein the mainly interaction sites are the hydrogen atoms on enediol of AA and the oxygen atom on carbonyl of urea. The electrochemical behavior of AA was significantly affected by above interactions. [ABSTRACT FROM AUTHOR]

• MASA was grown by solution growth method and it belongs to triclinic system. • All theoretical calculations were made using DFT/B3LYP/6-31+G(D) method. • NBO explains the intermolecular charge transfer interactions within the molecule. • Spectral analysis of MASA has been performed by FT-IR and FT-Raman techniques. • Z-Scan analysis was performed to show the NLO activity of the MASA crystal. Semi-organic nonlinear optical (NLO) melaminium sulfamate (MASA) single crystals were synthesized by slow evaporation method and analyzed by using X-ray diffraction, UV–vis, FT-IR and FT-Raman experiments. Single crystal X-ray diffraction (SXRD) analysis confirms that MASA crystal belongs to triclinic system with centrosymmetric space group P-1. The quantum chemical calculation were carried out using density functional theory (DFT) with B3LYP/6-31+G(d) basis set. The intermolecular interactions were deeply analyzed by NBO analysis. The molecule with intermolecular N-H⋯N and N-H⋯O hydrogen bonds show notable vibrational effect. The optical property of MASA was evaluated by UV–vis optical transmittance spectrum. Thermal stability of the grown crystal was performed by using TG-DTA analysis. The frontier molecular orbital analysis illustrates the charge transferred from sulfamate anion to melaminium cation. Hirshfeld and 2D fingerprint plot reveals the intermolecular N-H⋯O and N-H⋯N contacts of MASA molecule. The existence of various functional groups and vibrational modes are affirmed by Fourier transform infrared (FT-IR) and FT-Raman spectral analysis. Additionally, the molecular electrostatic potential (MESP) and topological analysis such as electron localization function (ELF), reduced density gradient(RDG), localized orbital locator(LOL) and atoms in molecule(AIM) have been used to predict the intermolecular interaction, especially the hydrogen bonds. The hydrogen atom from sulphamic acid was transferred to the melamine molecule giving the singly protonated melaminium cation. The outcome of SXRD, UV–visible, TG/DTA, HOMO–LUMO, NLO and Z-Scan values were compared with earlier reported compounds and amongst the analyzed compound MASA shows good NLO activity. The NLO activity of MASA was analyzed theoretically and experimentally by DFT and Z-scan method. [ABSTRACT FROM AUTHOR]

The 5-methoxy-1H-benzo[ d ]imidazole and the its silver(I) complex were characterized using elemental analysis and spectroscopic methods (1H NMR, FT-IR, and UV–Vis). To compare the spectroscopic results and establish the molecular structures of the free ligand and its metal complex, density functional theory (DFT) computations were performed. Quantum chemical properties were theoretically calculated. Finally, In vitro antimicrobial activity and molecular docking studies were performed. [Display omitted] The 5-methoxy-1H-benzo[ d ]imidazole (5MeOBM) and the synthesized new silver(I) complex were characterized using elemental analysis and spectroscopic methods such as 1H NMR, FT-IR, UV–Vis and mass spectrometry. To compare the spectroscopic results and establish the molecular structures of the free ligand and its metal complex, density functional theory (DFT) computations were performed. UV–Vis spectrum analysis was performed to better understand the optical properties, and quantum chemical properties were computed theoretically utilizing HOMO and LUMO energy levels. Topological analyses were carried out using Multiwfn to identify the complex's primary binding areas and weak interactions. NBO analyses were performed in order to predict potential reactivity features and critical intramolecular interactions. Biological study of the ligand and its Ag(I) complex were tested for their in vitro antimicrobial activities. The molecular docking investigations were performed to explore the possible interaction of each compound with an antimicrobial agent. Also, molecular docking studies were carried out to learn how these compounds interact with biomolecules. [ABSTRACT FROM AUTHOR]

[Display omitted] • Study of the interacting mechanism of curcumin in the NADES comprising Menthol, Myristic acid using DFT method. • Validation of the data using experimental techniques (FTIR, Raman and SERS) • and computational methods. • UV–vis spectral analysis is performed to assess the stability of the NADES complex. • Slow degradation of the curcumin is observed in Men-Myr-Cur solvent. • Men-Myr-Cur solvent can extract more curcumin from the raw turmeric rhizome. The present work is aimed at analyzing the structural and chemical properties of Natural Deep Eutectic Solvent (NADES) comprising Menthol, Myristic Acid, and Curcumin, employing both computational and experimental methods. The enchanting pursuit of this theoretical study is to unravel the amicable interacting sites of these compounds using Density Functional Theory (DFT) at B3-LYP/6–31 + G (d,p) basis set. The intramolecular and intermolecular charge transfer between the hydrogen bond acceptors (HBAs) and hydrogen bond donors (HBDs) are affirmed by the NBO (natural bond orbital) study and AIM (atoms in molecules) analysis of the titled compounds. Through first-order hyperpolarizability parameters, the application of NLO onto the molecules supports the enhancement of the electron transfer. This paper also accounts for the interacting nature of C O, O–H, and C–H vibrational modes of the Men-Myr-Cur compound (Menthol + MyristicAcid + Curcumin) using Raman Spectroscopic and Infrared techniques. The theoretically computed Raman and IR vibrational wavenumbers are found to be in good agreement with the experimentally obtained values of the Raman, SERS, and FTIR. Moreover, the molecular docking analysis against the 7U5B receptor yields a remarkable binding energy of −6.15 kcal/mol, indicating the significant bioactive nature of the complex. Solubility and stability of Curcumin, both extract and standard samples in NADES are tested. [ABSTRACT FROM AUTHOR]

[Display omitted] • Interaction of adenine (HPA) on pristine and doped coronene were studied theoretically using Density Functional Theory. • The adsorption strength and charge transfers in doped coronene are larger than that in the pristine coronene. • The change in electrical conductivity of coronene after the adsorption suggests its sensitivity towards DNA bases. • The predicted energy gap and the very long recovery time for adenine-coronene configurations indicate that pristine/doped coronenes has a potential application in DNA detection. Nucleobase detection is crucial for the exploration of specific nucleotide sequences. Inspired by the recent realization of two dimensional nanomaterials as DNA detectors as well as sensors, the interactions of pristine and B/N/O/P-doped coronenes with adenine nucleobase have been studied on the basis of Density Functional Theory. Optimal configurations, the corresponding adsorption energies, charge transfer and electrical properties have been calculated for each complex. The adsorption strength and charge transfer in doped coronene have been found larger than that in the pristine coronene. AIM-RDG study suggests that non-covalent interactions existing in the associated interactive region are responsible for the stability of the complexes. The change in electrical conductivity of coronenes after the adsorption indicates its sensitivity towards DNA bases. The predicted energy gap and the prolonged recovery time for adenine-coronene configurations imply that pristine/doped coronene has potential applications in DNA detection. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mercaptans were removed from fuels through Mg 12 O 12 nanotube using DFT quantum chemical calculations. • Mg 12 O 12 nanotube shows higher affinity for mercaptans adsorption with larger adsorption energy values. • The adsorption process is chemisorption, spontaneous and exothermic. • The atom in molecule analysis verified the existence of van der Waals and stronger intermolecular interactions. In the present study we used Mg 12 O 12 nanotube as adsorbent for the removal of sulfur containing compounds (Thiophene, Thiolane, etc) from fuel using DFT approach. Two different positions of nanotube were considered for adsorption of these compounds i.e. top and edge. The bond lengths and energetic analysis revealed that the edge position for adsorption is more preferred as compared to the top position. The shorter S Mg bond length was found for thiolane and sulfide adsorption which is equivalent to 2.5 Å (edge position) and 2.6 Å (top position). The higher negative adsorption energy −25.7 kcal/mol (edge position) and –22.98 and kcal/mol (top position) were noticed for thiolane adsorption. The NBO, RDG-NCI and AIM analysis was performed to find the strength and nature of intermolecular bonding between the adsorbent and adsorbate. The negative values of Δ H and Δ G suggests the exothermic, chemisorbed and spontaneous nature of adsorption process. [ABSTRACT FROM AUTHOR]

Abstract Intermolecular interactions of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf 2 N]) as an imidazolium-based ionic liquid, with three molecular liquids (MLs) including dimethyl sulfoxide (DMSO), methanol (MeOH) and acetonitrile (AN) had been examined by density functional theory (DFT) methods. All possible configurations of both cationic ([emim]⋯ML) and anionic ([Tf 2 N]⋯ML) complexes were considered and investigated. It was found that configuration No. 5 was the most stable configuration of [emim][Tf 2 N] in all environments while the minimum configurational relative energy of cationic complexes was observed for configuration No. 1. In anionic complexes, it shifted between configuration No.1 and No.3 for different complexes in different environments. Calculated interaction energies showed that replacement any of the [emim][Tf 2 N] parts with a ML molecule decreased the intermolecular interactions. Among molecular liquids, stronger intermolecular interactions were observed for DMSO which was consistent with experimental results. It was shown that electrostatic interactions, charge transfer energies and hydrogen bond power are responsible for interaction energy changes. In both [emim]⋯ML and [Tf 2 N]⋯ML complexes, some intermolecular hydrogen bonds were detected using AIM results. Among them, DMSO formed stronger hydrogen bonds than MeOH and AN with both cationic and anionic portions, which was compatible with experimental results about hydrogen bonding power. Our results quantitatively showed, why mixing ionic liquids with molecular liquids is one of the ways to modulate their viscosity. Graphical abstract Unlabelled Image Highlights • All possible interactions between an IL and three MLs were evaluated theoretically. • Geometrical, energetical and topological analysis were done. • Configurational effect on these interactions was determined. • Effective factors on configurational interaction energies were determined. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Isoniazid (INH) drug adsorption on pristine magnesium oxide nanocage (MgONC) investigated by DFT, AIM, and NBO calculations. • To improve the detection of INH on the pristine MgONC, we investigated pristine MgONC by doping with Al atoms. • The (INH) drug shows strong interactions with the Al-doped MgONC, which may Al-doped MgONC used as a bio-sensor for the detection of INH drug. Abstract Density functional theory (DFT), quantum theory of atom in molecule (QTAIM), and natural bond orbital (NBO) have been performed for geometry optimization, binding energy, electronic properties, and adsorption of drug isoniazid (INH) on the pristine and Al-doped Mg 12 O 12 nanocage (MgONC). This drug has tendency to attach via its nitrogen and oxygen atoms to the Mg atoms of the nanocage with adsorption energy in range of −0.96 to −2.58 eV based on the dispersion corrected M062X level of theory. Isoniazid was found to be properly adsorbed on the MgONC while the electronic properties of the MgONC was not significantly changed. But, Al-doped MgONC presents high sensitivity to isoniazid, compared with the pristine nanocage structure, particularly the Al doped one was changed dramatically. The Al-doped MgONC can adsorb isoniazid more strongly with adsorption energy (E ads) equal to −2.58 eV, corresponding to the stable configurations. The QTAIM analysis was investigated for both type's of structural aspects and electronic properties associated with adsorption processes on the MgO nanocage. Furthermore, NBO analysis indicated a stronger donor–acceptor interactions with INH drug and MgONC. Our calculations showed that the HOMO/LUMO gap of the Al-doped MgONC is significantly changed after the adsorption of INH molecule corresponding to the most stable configuration that gives rise enhance the electrical conductivity of the MgONC. In conclusion, the electronic properties of Al-doped MgONC are strongly sensitive to the presence of INH molecule and therefore it can be used in (bio) sensor devices and can be used to trace the drug via spectrophotometric techniques in the body. [ABSTRACT FROM AUTHOR]

Abstract In the present work, we apply density functional theory (DFT) calculations to investigate the drug delivery performance of the boron nitride nanotube (BNNT) having hydroxyl functional groups (-OH) for Carmustine (BCNU) agent in the gas phase and water environment. Based on the DFT results, it is found that the interaction between BCNU molecule and functionalized boron nitride nanotube (f-BNNT) is weak; so that, the adsorption of the BCNU drug on the nanotube surface is typically physisorption. Based on the structural characteristics, the stability of the BCNU/f-BNNT complexes contributed to the formation of the intermolecular hydrogen bonds (HBs) between the BCNU drug and hydroxyl groups of BNNT which confirmed by Bader theory of atoms in molecules (QTAIM) results. Our theoretical results show that the structural properties of BCNU molecule doesn't significantly change upon adsorption of drug molecule on f-BNNT. Moreover, the natural bond orbital (NBO) analysis show in BCNU/f-BNNT complexes, the charge transfers from f-BNNT to Carmustine drug and the electronic properties of BCNU drug are not affected during the adsorption process on the nanotube surface. Finally, the effects of drug concentration and temperature on the adsorption mechanism of BCNU molecules are investigated by molecular dynamics (MD) simulation. Such results provide valuable information on the potential applications of functionalized boron nitride nanotubes in the fields of drug delivery within biological systems. Highlights • The physical nature of drug adsorption on the f-BNNT. • BCNU can be formed intermolecular HBs with hydroxyl groups of BNNT. • By increasing drug concentration, the stabilities of complexes increase. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The structural and vibrational analyses of the compound under investigation are reported. • The DFT method was used to obtain the vibrational wavenumber, chemical shifts and electronic absorption wavelengths. • Molecular docking studies suggest that the compound exhibit antifungal property. Abstract Dithiocarbamate coumarin derivative (5, 7-Dimethyl-2-oxo-2H-chromen-4-yl)-methyl diethyldithiocarbamate (DCMDC) was synthesized and chemical structure was resolved using spectroscopic techniques such as GC-MS, 1H NMR, 13C NMR and FT-IR. Quantum mechanical calculations of energies, geometries and vibrational parameters of DCMDC were done for the first time using density functional theory (DFT) applying B3LYP method with 6-311++G(d,p) basis set of Gaussian'09 package. Natural bond orbital (NBO) calculation and AIM analyses were performed to elucidate intra-molecular interactions and delocalisation of electron density within the molecule. Molecular docking studies were carried out using Schrodinger software to find the anti- microbial activity and revealed that DCMDC has potential antifungal activity. [ABSTRACT FROM AUTHOR]

B3LYP and MP2 methods with the most popular basis set, 6-311++G(d,p) are applied to optimize the equilibrium conformers of 4-amino-3-pentene-2-thial. Furthermore, to have more reliable energies, the total electron energies of all forms are recomputed at the CBS-4M level of theory. A theoretical investigation of the equilibrium conformers clearly shows that various intramolecular hydrogen bonds (IHBs) such as N-H...S, S-H...N, S-H...π, C-H...N, and C-H...S are the most effective factors in the conformational preference of thialamine, thiolimine, and thialimine groups. Hence, the IHB strengths are evaluated in various resonance-assisted hydrogen bond systems by geometrical factors, topological parameters, and charge transfers corresponding to orbital interactions. Also, the solvent effect on the IHB strength is considered using Tomasi′s PCM. Our results in the gas phase reveal that the thialamine group has extra stability with respect to thiolimine and thialimine ones. The population analyses of all the possible conformers by the NBO method predict that the origin of this tautomeric preference is mainly due to more significant π electron delocalization in the framework of thialamine forms, especially πC=C → π C = S* and Lp(N) → π C = C* charge transfers. Moreover, the excited state properties of IHBs in these systems are investigated theoretically using the time-dependent DFT method. [ABSTRACT FROM AUTHOR]

Abstract The [Ag(Menic) 2 (ClO 4)] 2 , (1) and [Ag(NA) 2 ]ClO 4 , (2) complexes, where Menic; methylnicotinate and NA; nicotinamide, were synthesized and characterized using elemental analysis, FTIR, NMR and single crystal X-ray diffraction combined with DFT calculations. The Ag(I) is coordinated with two organic ligand molecules in both complexes. In 1 , the coordination sphere is completed by one ClO 4 ¯ anion as a monodentate ligand while in 2 , the ClO 4 ¯ anion is in the outer sphere. Both complexes showed some argentophilic interactions where the Ag Ag distance is shorter in 1 (3.152(6) Å) than 2 (3.303(9) Å). The organic ligands showed no antimicrobial activity up to 15 mmole/L while both silver(I) complexes are biologically active against different bacterial strains and the fungus Candida albicans. The minimal inhibition concentrations (MICs) of the Ag(I) complexes are in the range of 4–8 mmol/L depending on the nature of microorganism. Complex 2 showed slightly better antifungal action than 1. In contrast, complex 1 showed higher antibacterial potency against P. aeruginosa, C. perfringens, Sh. sonnei and Str. pneumonia compared to 2. The antibacterial action of 2 is slightly higher or equal against the rest of microorganisms compared to 1. The strength and nature of the Ag Ag, Ag N and Ag…O interactions were analyzed using atoms in molecules and natural bond orbital calculations. Graphical Abstract Unlabelled Image Highlights • Two Ag(I) complexes with nicotinic acid derivative as ligands were synthesized. • Their structures were determined using FTIR, NMR, XRD and DFT studies. • Ag O interactions are weak while Ag N bonds are significantly strong. • Both complexes have potent antimicrobial activities while the ligands are inactive. [ABSTRACT FROM AUTHOR]

Self assembly of Mn(II) perchlorate and bis(pyrazolo)- s -triazine pincer ligand ( L ) in methanol-water mixture afforded the homoleptic [MnL 2 ](ClO 4 ) 2 complex ( 1) as plate colorless crystals. Following the crystallization process till the near dryness of the solution, we noted few needle like crystals of the heteroleptic [MnL(H 2 O) 3 ](ClO 4 ) 2 ·H 2 O complex ( 2 ). Their molecular and supramolecular structures were analyzed using single crystal structure combined with Hirshfeld analysis. The packing of complexes 1 and 2 is dominated by weak C H⋯O and strong O H⋯O hydrogen bonds, respectively, as well as anion-π stacking interactions. Using Hirshfeld analysis, the percentages of the O⋯H intermolecular contacts are 32.7% and 36.8% for 1 and 2 , respectively. The Mn N distances correlated well with the atoms in molecules (AIM) topological parameters. The amount of electron density transferred from the ligand units to the manganese centre are nearly the same (0.9 e) in both complexes. [ABSTRACT FROM AUTHOR]