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A comprehensive approach encompassing a blend of spectral techniques and Density Functional Theory (DFT) was employed to elucidate the electronic, vibrational, structural, and nonlinear optical properties of 2,3-dimethyl-N[2-(Hydroxy)benzylidene] aniline (DNHBA). The investigation of this chemical compound involved a meticulous examination using spectroscopic techniques (FTIR, FT-Raman). The DFT calculations utilized the B3LYP method in conjunction with 6-311G (d, p) basis sets. The findings were substantiated by comparing the estimated vibrational frequencies and molecule geometry with experimental data. Using the Time Dependent −Density Functional Theory (TD-DFT) method to calculate the energy band gap of the compound at different solvents. We looked into frontier molecular orbitals (FMO) Molecular electrostatic potential (MEP) and natural bond analysis (NBO) to determine the compound’s kinetic stability and chemical reactivity. Hirshfeld surface (HS) analysis calculated the O–H..O, H-H and intermolecular interaction energy of the compound. The electron density distribution, interactions, and excitation within the title molecule are illustrated by performing topological analyses (RDG, ELF and LOL) using the Multiwfn software. In addition to these assessments, molecular dynamics provides an understanding of the system's dynamic development over a predefined duration during which atoms and molecules are permitted to interact. Utilizing the molecular docking approach allows us to energize the atomic-level interplay between small molecules and proteins within the binding sites of target proteins. This approach enhances our comprehension of vital biochemical processes associated with the behavior of small molecule. The intricacy and hazards associated with drug discovery and development processes have increased dramatically, leading to higher drug research costs.

In this study, the optimal geometry and vibrational assignments of 2-methyl-4-hydro-1,3,4-triazol-thione-5, one of the triazole derivatives, were analysed by the DFT approach and vibrational spectroscopy. PED values were calculated, and vibrational assignments were determined. Experimental results showed that interactions between 2-methyl-4-hydro-1,3,4-triazol-thione-5 and solvent (acetone, acetonitrile, dioxane, and DMF) molecules lead to a red shift of the N-H stretching vibrational band. The computations were performed at the B3LYP/6-311++G(d,p) functional set. The molecular electrostatic potential surface was used to distinguish between electrophilic and nucleophilic regions. The reactivity of the molecular complexes was determined by examining their frontier molecular orbitals. Topological investigations revealed the existence of N-H…N and N-H…O-type hydrogen bonds between 2-methyl-4-hydro-1,3,4-triazole-thiol-5 and solvent molecules. The red-shift of the N-H stretching band and H-bond strength between solute–solvent molecules are in the order of acetonitrile, acetone, dioxane, and DMF.

In this research paper, (C6H9N2)2[CdCl4], was effectively synthesized using the slow solvent evaporation procedure. Single crystal X-ray diffraction (scXRD) analysis revealed that the compound crystallizes in the triclinic system, specifically in the space group P 1¯. Powder XRD (PXRD) of the bulk material showed some minor impurities. The atomic arrangement of the title structure comprises discrete tetrahedral groups [CdCl4]2− linked to the organic entities through weak N(C)H…Cl hydrogen bonds. Solid-state contacts were further studied through Hirshfeld surface analyses, complemented by 2D fingerprint plots. Computational results, obtained using the B3LYP tool with 6-311++G(d,p) + LANL2DZ mixed basis set, demonstrated consistent geometrical, vibrational, and electronic features to the experimental data. Non-covalent interactions were explored in depth using Atoms-In-Molecule (AIM) and Reduced Density Gradient (RDG) analyses. Thermogravimetry (TG) and Differential Scanning Calorimetry (DSC) analyses showed melting at 378 K and decomposition at around 540 K. Furthermore, the inhibition activity of the examined compound was explored in-silico through molecular docking studies targeting the inducible Nitric Oxide Synthase (iNOS) enzymes.

An Fe(III)-carbonato six-coordinate picket fence porphyrin complex with the formula [K(2,2,2-crypt)][FeIII(TpivPP)(CO3)]·C6H5Cl·3H2O (I) has been synthesized and characterized by UV-Vis and FT-IR spectra. The structure of (carbonato)(α,α,α,α-tetrakis(o-pivalamidophenyl)porphinato)ferrate(III) was also established by XRD. The iron atom is hexa-coordinated by the four nitrogen atoms of the pyrrol rings and the two oxygen atoms of the CO32− group. Complex I, characterized as a ferric high-spin complex (S = 5/2), presented higher Fe-Np (2.105(6) Å) and Fe-PC (0.654(2) Å) distances. Both X-ray molecular structure and Hirshfeld surface analysis results show that the crystal packing of I is made by C-H⋯O and C-H⋯Cg weak intermolecular hydrogen interactions involving neighboring [FeIII(TpivPP)(CO3)]− ion complexes. Computational studies were carried out at DFT/B3LYP-D3/LanL2DZ to investigate the HOMO and LUMO molecular frontier orbitals and the reactivity within the studied compound. The stability of compound I was investigated by analyzing both intra- and inter-molecular interactions using the 2D and 3DHirshfeld surface (HS) analyses. Additionally, the frontier molecular orbital (FMO) calculations and the molecular electronic potential (MEP) analyses were conducted to determine the electron localizations, electrophilic, and nucleophilic regions, as well as charge transfer (ECT) within the studied system.

The inclusion of the majority of heterocycle fragments in the pharmaceutical arena currently on drug discovery, combined with their inherent adaptability and distinctive physicochemical features, has established them as true pillars of therapeutic/medicinal chemistry. Besides from the medications, numerous others are being researched for their potential anti-carcinogenic behavior. In this current study, a newly synthesized TTCPE molecular structure from carbinol extract of Aeglemarmelos leaves has been confirmed by GC–MS results, and structural characteristics are reported. The quantum chemical simulated calculations were employed using a versatile basis set -B3LYP/6-311++G(d,p) approach. The optimized structure with the minimum energy confirmation was carried out using Potential scan energy (PES) analysis and the optimized with atom numbering scheme of TTCPE discovered strength of the bond parameters and compared with XRD data. Experimental and theoretical spectral characterizations were accomplished and the vibrational wavenumbers provide an affordable correlation with the experimental value. The UV–vis electronic spectra associated with the gas phase and various solvent-liquid phases were obtained by TD-SCF methods. The high stabilization energy E(2) value is 128.06 kcal/mol executed by the NBO method along with the lone pair of interaction types in the header composite. The MEP map, HOMO-LUMO- intermolecular charge transfer (ICT) was completed by gas and different solvents and their corresponding energy parameters were evaluated. Fukui function describes reactive sites on TTCPE that were investigated. The topological analysis of LOL, ELF, and RDG was performed. The five principles of Lipinski are used to perform drug-likeness qualities. Furthermore, a molecular docking technique was used to compare ligand to several protein inhibitor targets (1H8X, 6R7T, and 6DX5) and the corresponding parameters were calculated. As a result, the header composite identifies an alternative anticancer treatment agent.

The chemical structure of 2-Bromo-6-nitrotoluene was optimized using the B3LYP/6–311++G (d, p) basis set and density functional theory. Calculations were made on the molecules of the substance 2-Bromo-6-nitrotoluene's geometrical-parameters. A variety of DFT techniques, including border atomic orbitals, essential binding orbitals, local reaction descriptors, and molecular electrostatic potentials, are worn to test the reactivity of molecules. Several solvents (water, benzene and DMSO) were examined by UV–vis spectroscopy and vapor phase electronic transition. Estimated efficiency for the most heavily inhabited molecular orbital and even the least vacant molecular orbital describes electron excitation properties. Environmental toxicity, pharmacological similarity, localized orbital location, and electron localized function were assessed. To evaluate the material's metabolic processes, chemical interaction modelling was used. In conclusion, this paper offers a thorough investigation combining spectroscopic and quantum computational methods to evaluate the metabolic function and solvation impact of selected therapeutic substances. The information gathered is therefore very useful in planning for future study.

In this investigation a single crystal of (4-oxo-piperidinium ethylene acetal) trioxonitrate (4-OPEAN) was synthesized by modifying the mechanism of gradual evaporation at ambient temperature. The operational groupings are found in the complex material in the elaborate substance, according to the infrared spectrum. Single crystal X-ray diffraction suggests, (4-OPEAN) with the chemical formula (C7H12NO2)NO3 belongs to the orthorhombic space group Pnma and is centrosymmetric in three dimensions with the aforementioned network configurations, a = 11.7185(8) Å, b = 7.2729(6) Å, c = 11.0163(8) Å, Z = 4, V = 938.89(12) Å3, R = 0.0725 and wR = 0.1762. Many NH…O and CH…O hydrogen bridges, both bifurcated and non-bifurcated, link the 4-oxo-piperidinium ethylene acetal cations to the trigonal (NO3−) anions. Molecular geometry and optimal parameters of (4-OPEAN) have been determined via DFT computations at the theory-level B3LYP/6-311 ++ G(d, p), these have been contrasted with the X-ray data already available. Hirshfeld surface analysis has made it possible for the visualization and quantification of relationships between molecules in the crystal composition. Quantum theory atoms in molecules, electron location function, decreased density gradient, and localized orbital locator research have all been used to explore non-covalent interactions in crystal structure. In order to pinpoint both the nucleophilic and electrophilic locations that support hydrogen bond formation, the molecule electrostatic potential was determined. The greatest and lowest energies of occupied and unfilled molecular orbitals, together with additional derived atomic characteristics, show the material to be extremely stable and hard. According to a molecular docking study, 4-OPEAN may exhibit inhibiting effects on the 6Y84 and 7EJY virus proteins from corona (COVID-19).

The thermophysical properties of 1A2P (1-amino-2-propanol) (1) with AAc (methyl acetate (MAc) or ethyl acetate (EAc) or propyl acetate (PAc) or butyl acetate (BAc)) (2) were examined for understanding the molecular interactions between given binary liquid mixtures. Viscosity (η) was measured for 1A2P, AAc (alkyl acetate) and their binary mixture at five different temperatures (T = 298.15 to 318.15 K) and at 0.1 MPa pressure. From η data, the deviation in viscosity, Δη, and excess Gibbs free energy of activation, G∗E, were calculated. The Δη values were more positive for the 1A2P (1) + MAc (2) binary mixture at equimolar composition which indicate that there is strong intermolecular interaction between 1A2P and MAc molecules. Further, Δη values were also analyzed by Graph theoretical approach (GTA) and predicted that CO-----H-O interactions are stronger than OH----O-C interactions between 1A2P and AAc molecules in the liquid mixture which is also recognized by FTIR spectroscopic studies. Density functional theory (DFT) studies were employed to investigate the strength of molecular interactions.

An advanced organic–inorganic hybrid compound 1,1,4,7,7-pentamethyldiethylenetriammonium trinitrate (PMDT) has been synthesized and characterized by X-ray diffractometry. The title molecule is abbreviated as PMDT has been investigated using experimental and computational techniques. The quantum chemical study was carried out using DFT calculation with B3LYP/6–31++G(d, p) basis set. Different methods have been performed to quantify the non covalent interactions within the title molecule. Atoms In Molecules (AIM) approach at bond critical points BCP's of the hydrogen bonds (C–H…O and N–H…O) in PMDT have been applied. Electron localization Function (ELF) and Local Orbital Locator (LOL) methods were studied in order to detect the electron density at bonding and anti-bonding sites of the title compound. The Hirshfeld surface analysis exposes important information on the inter and intramolecular interactions present in the crystal structure. Further characterization of the non covalent interactions has been shown by reduced Density of Gradient (RDG) and Independent Gradient Model (IGM). In addition, to map and analyze the weak-interaction regions, the interaction region indicators (IRI) have been used. The effect of polar solvents for the electrophilic and nucleophilic sites has been investigated. The ChELPG and Mulliken population analyses have been carried out. Frontier molecular orbital's (HOMO-LUMO) was discussed to afford the information about the reactivity of the PMDT molecule in gas, water and DMSO solvation. The temperature behavior and conductivity of the title molecule have been analyzed. Finally, in order to estimate the antibacterial mechanism of the PMDT compound action, molecular docking calculations were carried out on the active sites of various proteins.

Using the methods of IR-spectroscopy and quantum chemical calculations, we determined the formation of an H-bond between the 1,2,3-benzotriazole molecule and the molecules of acetone, dioxane, DMF, and DMSO. Quantum chemistry methods have been used to calculate the sums of charge changes in the atoms of the 1,2,3-benzotriazole molecule and of proton acceptor molecules (acetone, dioxane, DMF, and DMSO) due to the formation of their complexes with an H-bond (H-complexes NH…O). The sum of charge changes was taken as a contribution of a covalent component to H-bond formation. It has been established that as the sum of charge changes in N, H, and O or H and O, forming the H-complex, increases, the enthalpy of H-complex formation (EF) decreases. On the contrary, the EO of H-complexes increases when the product of the initial charges on the H and O atoms increases. In the absence of H-complexes, the product of charges was considered the electrostatic component of H-bond formation. The criterion of the value of H-bond EF was the value of a low-frequency shift of the initial position of the maximum IR absorption band of the NH vibration of the 1,2,3-benzotriazole molecule relative to its position in a neutral CCl4 solvent. The results of QTAIM, NCI, and RDG analyses showed that the values of energy densities in BCPs have a positive value in the complexes formed by 1,2,3-benzotriazole with acetone, dioxane, and DMFA, and such hydrogen bonds are electrostatic in nature. In the complex formed by 1,2,3-benzotriazole and DMSO, it has a negative value and a covalent character. The data obtained have allowed for two main conclusions: (i) In the formation of the H-complexes of the 1,2,3-benzotriazole molecule with proton-acceptor molecules containing oxygen atoms, the main contribution to H-bond formation is made by the electrostatic component. (ii) The contribution of the covalent component increases with increasing enthalpy of H-bond formation.

A series of novel 3-alkylated indoles were synthesized in good yields under mild reaction conditions using inexpensive, readily available, and environmentally benign glycolic acid catalyst. This new catalytic multicomponent reaction is attractive for diversity-oriented synthesis involving C–C bond formation. This strategy has a number of advantages, such as a simple work-up procedure, and short reaction time. Antimicrobial studies were carried out and the para-nitro-substituted compounds were found to be good inhibitors of Aspergillus niger. This activity explained by interacting with active site residues such as MET816, PHE786, and PHE820 of the target fungal protein, phosphodiesterase-5 (PDE5) (PDB:2H44). Furthermore, the SwissADME online application was used to analyses the physicochemical and pharmacokinetic features of the compounds (6–10).

In this work, we studied intermolecular aqueous clusters of biuret, an important urea derivative. FTIR showed an increase in the intensity of absorption bands when water molecules are introduced into the biuret. X-ray diffraction analysis showed that the introduction of water molecules into the biuret structure significantly increases the intensity of the bands on the diffraction patterns in the range from 14 to 65 2˚⊖. Aqueous biuret clusters have also been studied in the gas phase by theoretical methods: density functional theory and Atoms in Molecules (AIM) using the DFT level B3LYP/6–31 + G (d, p). The nature of molecular interactions between water and biuret through hydrogen bonds was also investigated using the electron localization function (ELF) and non-covalent reduced density gradient (NC-RDG). The thermodynamic and Non-linear optical properties of biuret-water clusters were performed also.

Isopropyl 1-benzoyl-4-(benzoyloxy)-2,6-diphenyl-1,2,5,6-tetrahydropyridine-3-carboxylate (IDPC) was synthesized and characterized via spectroscopic (FT-IR and NMR) techniques. Hirshfeld surface and topological analyses were conducted to study structural and molecular properties. The energy gap (Eg), frontier orbital energies (EHOMO, ELUMO) and reactivity parameters (like chemical hardness and global hardness) were calculated using density functional theory with B3LYP/6–311++G (d,p) level of theory. Molecular docking of IDPC at the active sites of SARS-COVID receptors was investigated. IDPC molecule crystallized in the centrosymmetric triclinic (P1¯) space group. The topological and Hirshfeld surface analysis revealed that covalent, non-covalent and intermolecular H-bonding interactions, and electron delocalization exist in the molecular framework. Higher binding score (-6.966 kcal/mol) of IDPC at the active site of SARS-COVID main protease compared to other proteases suggests that IDPC has the potential of blocking polyprotein maturation. H-bonding and π-cationic and interactions of the phenyl ring and carbonyl oxygen of the ligand indicate the effective inhibiting potential of the compound against the virus.

The stoichiometric ratio 2:1 mix of 1-phenylpiperazine and oxalic acid dihydrate followed by slow evaporation results in a new material, bis(4-phenylpiperazin-1-ium) oxalate dihydrate, with the general chemical formula (C10H15N2)2(C2O4).2H2O, indicated by PPOXH. The title compound’s asymmetric unit and three-dimensional network have been determined by single crystal X-ray diffraction. Intermolecular O-H…O, N-H…O and C-H…O hydrogen bonding assist in maintaining and stabilization of the crystal structure of this new compound. Hirshfeld surface analysis and two-dimensional fingerprints have been performed to quantify the non-covalent interactions in the PPOXH structure. The vibrational modes of the different characteristic groups of the title chemical were identified using infrared spectrum analysis. The thermal characterization of this product was studied by a coupled TG/DTA analysis. The ultraviolet-visible absorption spectrum has been used to study the optical properties and the energy gap of this compound. DFT calculations were employed to evaluate the composition and properties of PPOXH. The analysis of HOMO-LUMO frontier orbitals analysis allows us to understand the chemical reactivity of this supramolecular compound and to determine the electrophilic and nucleophilic sites responsible for electron transfer. Topological analysis (AIM), reduced density gradient (RDG), molecular electrostatic potential surface (MEPS) and Mulliken population were analyzed to evaluate the types of non-covalent interactions, localization of electrons in space, atomic charges and molecular polarity in depth.

The molecular geometries of the possible conformations of pyruvic acid–water complexes (PA-(H2O)n = 1–4) have been fully optimized at DFT/B3LYP/6-311G++ (d, p) levels of calculation. Among several optimized molecular clusters, we present here the most stable molecular arrangements obtained when one, two, three, and four water molecules are hydrogen-bonded to a central pyruvic acid molecule. Appropriate topological and geometrical parameters are considered primary indicators of H-bond strength. Atoms in molecules analysis shows that pyruvic acid can form a ring structure with water, and the molecular structures are stabilized by both strong O–H⋅⋅⋅O and C–H⋅⋅⋅O hydrogen bonds. In large clusters, classical O–H⋅⋅⋅O hydrogen bonds still exist between water molecules, and a cage-like structure is built around some parts of the central molecule of pyruvic acid.

This study reported the combination of advanced statistical physics modeling and density functional theory (DFT) investigation for the interpretation of the adsorption of Paprika dye on TiO2 surface for dye sensitized solar cells. By using a statistical physics modeling method, an adequate monolayer model with four energies was successfully used to interpret the adsorption process at a macroscopic level. The DFT simulation has been used to study the interaction of the Paprika dye on TiO2 surface to understand some of the atomistic details that are crucial to the dye/semiconductor interaction. We pay particular attention to the adsorption modes, geometries and energies between the paprika dye and TiO2. The DFT simulation determined different binding modes which participated in the adsorption of Paprika dye on TiO2 surface: monodentate coordination via hydrogen atom bond, monodentate coordination via oxygen atom bond and bidentate coordination via two oxygen atoms bond. In particular, calculations showed that the interaction between the paprika dye and TiO2 is strengthened with the bidentate coordination mode via the two hydroxyl and ether functionalities groups involved in the adsorption process. Keywords: Paprika oleoresin dye, Statistical physics modeling, DFT simulation, Adsorption isotherms, Dye sensitized solar cells

The structure, spectroscopic features, and pharmaceutical effect of N′-(4-Methoxybenzylidene)-5-phenyl-1H-pyrazole-3-carbohydrazide (MBPPC) has been studied by DFT modeling, X-ray diffraction, FT-IR, 1H and 13C NMR, and molecular docking investigation. Molecular structure analysis was carried out using DFT calculation. Then, the low RMSD value indicates the good agreement between calculated and observed data. In order to understand the electronic charge transition, the electron difference density technical was performed. 1H and 13C NMR spectra were recorded in the region of 0–15 and 5–225 ppm, respectively, and FT-IR spectrum of MBPPC was obtained from 4000 to 500 cm−1. Electronic structure characteristics were achieved at the level of B3LYP/6-311+G(2d,p). Inter and intramolecular interactions are discussed by topological (AIM, RDG) and Hirshfeld surface analyses. TD-DFT calculations were conducted to reveal molecular orbital based reactivity characteristics and nonlinear optical features up to third order. In addition, thanks to the broad biological field of compounds based on pyrazole and hydrazone groups, molecular docking of the title compound was carried out to study their clinical activities. Docking simulation shows the potential of MBPPC against Vibrio cholera, Mycobacterium tuberculosis, and estrogen receptor.

The aim of this work is the preparation and the crystallization of new organic–inorganic hybrid compound including cyclohexylamine and [CoCl4]2−, (C6H14N2)3[CoCl4]Cl. Our compound has been studied by single-crystal X-ray diffraction (XRD), IR and TG-DTA examination. The XRD investigation allows to structurally distinguish our material by its monoclinic system and P21/n space group through the lattice parameters a = 15.2645 (12) Å, b = 10.0843 (7) Å, c = 17.4450 (13) Å, β = 95.957 (3)° and Z = 4. The crystal arrangement shows inorganic entities of [CoCl4]2− and chloride spreading in (10 1-) plane which are connected to cyclohexylammonium cations via N(C)–H…Cl H-bonds. The experimental studies on the compound have been accompanied computationally by DFT calculations via the B3LYP functional. The intermolecular interactions using were quantitatively studied by 3D-HS coupled with two dimensional fingerprint (2D-FP) plots and analyzed by the RDG and AIM approaches. The electron localization function (ELF) investigation was performed to explain the chemical structure of (C6H14N2)3[CoCl4]Cl.

In this paper, both methods (DFT and HF) were used in a theoretical investigation of 3-bromo-2-Hydroxypyridine (3-Br-2HyP) molecules where the molecular structures of the title compound have been optimized. Molecular electrostatic potential (MEP) was computed using the B3LYP/6-311++G(d,p) level of theory. The time-dependent density functional theory (TD-DFT) approach was used to simulate the HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) on the one hand to achieve the frontier orbital gap and on the other hand to calculate the UV–visible spectrum of the compound in gas phase and for different solvents. In addition, electronic localization function and Fukui functions were carried out. Intermolecular interactions were discussed by the topological AIM (atoms in molecules) approach. The thermodynamic functions have been reported with the help of spectroscopic data using statistical methods revealing the correlations between these functions and temperature. To describe the non-covalent interactions, the reduced density gradient (RDG) analysis is performed. To study the biological activity of the compound of the molecule, molecular docking studies were executed on the active sites of BRD2 inhibitors and to explore the hydrogen bond interaction, minimum binding energies with targeted receptors such as PDB ID: 5IBN, 3U5K, 6CD5 were calculated.

Essential oils are volatile oil-like liquids with a characteristic strong smell and taste. They are formed in plants and are then extracted. Essential oils have extremely strong physiological and pharmacological properties, which are used in the medicine, cosmetics, and food industries. In this study, the molecules caryophyllene oxide, β-pinene, 1,8-cineol, α-cubebene, and β-caryophyllene, which are the molecules with the highest contents in the essential oil of the plant mentioned in the title, were selected and theoretical calculations describing their interactions with water were performed. Because oil–water mixtures are very important in biology and industry and are ubiquitous in nature, quantum chemical calculations for binary mixtures of water with caryophyllene oxide, β-pinene, 1,8-cineol, α-cubebene, and β-caryophyllene were performed using the density functional theory (DFT)/B3LYP method with a basis of 6–31 G (d, p). Molecular structures, HOMO–LUMO energies, electronic properties, reactivity (ELF, LOL, and Fukui), and NCI-RDG and molecular electrostatic potential (MEP) on surfaces of the main components of Phlomis bruguieri Desf. essential oil were calculated and described.

In this paper, a novel hybrid material, entitled histaminium bis(trioxonitrate), with the general chemical formula (C5H11N3)(NO3)2, denoted by HTN was presented. Single-crystal X-ray diffraction was used to determine the structural characteristics of this compound after it was made using a slow evaporation method at room temperature. This compound was elaborated and crystallized to the monoclinic system with space group P21/c, and the lattice parameters obtained were: a = 10.4807 (16)Å, b = 11.8747 (15)Å, c = 16.194 (2)Å, β = 95.095 (6)°, V = 2007.4 (5)Å3 and Z = 8. The title compound’s atomic structure couldbe modeled as a three-dimensional network. Organic cations and nitrate anions were connected via N–H...O and C–H...O hydrogen bonds in the HTN structure. The intermolecular interactions responsible for the formation of crystal packing were evaluated using Hirshfeld surfaces and two-dimensional fingerprint plots. The compound’s infrared spectrum, which ranged from 4000 to 400 cm−1, confirmed the presence of the principal bands attributed to the internal modes of the organic cation and nitrate anions. Additionally, spectrofluorimetry and the ultraviolet–visible spectrum was used to investigate this compound. DFT calculations were used to evaluate the composition and properties of HTN. The energy gap, chemical reactivity and crystal stability of HTN were quantified by performing HOMO-LUMO frontier orbitals analysis. Topological analysis (AIM), Reduced Density Gradient (RDG), molecular electrostatic potential surface (MEPS) and Mulliken population were processed to determine the types of non-covalent interactions, atomic charges and molecular polarity in detail.

The (5α,6α)-7,8-didehydro-4,5-epoxy-17-methylmorphinan-3,6-diol (morphine)molecule has been studied using the density functional theory and molecular docking methods and non covalent interactions. The conformational analysis of the molecule at the B3LYP/6−311++G** and HF/6−311++G** levels has been made. The comparison of the structural parameters computed using the B3LYP function with the experimental data has revealed their good agreement. The weak intermolecular interactions in the morphine structure have been analyzed using several techniques. The Hirshfeld surface study has been carried out to identify the diverse intermolecular interactions (mainly hydrogen bonds) and the … π stacking interactions. The analysis of the topological (AIM, ELF, LOL) and non covalent (RDG, IRI, DORI) interactions has revealed different categories of inter- and intramolecular contacts on the basis of the electron localization density and color scale indicator, respectively. The molecular docking study has been carried out to examine the possibility of biological application of the title conformer using the 1DLO (cancerous), 2BK3 (Parkinson), 3LN1 (inflammatory), 4HOE (microbial), and 5 K95 (schizophrenia) enzymes. The analysis has shown that the morphine structure can be used not only in analgesia, but also in the treatment of diseases. The investigated compound has shown good results with monoamine oxidase B (MOAB) at a score of −105.04 kcal/mol.

In this paper, experimental and theoretical results of 2-(3, 4-dihydroxyphenyl) ethanaminium nitrate (2DOPN) have been investigated. From DFT calculations, molecular geometry and optimized parameters of 2-(3, 4-dihydroxyphenyl) ethanaminium nitrate have been obtained at B3LYP/ 6–311 ++ G(d, p) level of theory and compared with the available X-ray data. The non covalent interactions of the crystal structure were investigated by QTAIM analysis, ELF, LOL and Hirsfeld surfaces. In addition to study the weak interaction, a visualized approach known as RDG has been carried out. Mulliken atomic charge has been used to describe the process of electronegativity equalization and charge transfer in chemical reactions. NBO analysis was also performed to find the charge transfer within the molecule and their stabilization energy. Electronic proprieties such as MEP, ESP and the frontier molecular orbital analysis HOMO-LUMO of molecule were studied. The dipole moment (µ) and the first hyperpolarisability (β0) have been calculated and found that our compound is a potential NLO material. Thermal behavior (TGA and DTA) of C8H12NO2 (NO3) have also been undertaken and reported. The biological activity of 2DOPN through ligand and proteins interactions has been confirmed theoretically for the treatment of Parkinson disease with respect to chosen proteins. The activities of our molecule with divers proteins were studied in accordance with literature survey and the results were presented here.

In this work, experimental spectroscopic and theoretical methods as quantum chemical calculation were performed for 3-chloro-r(2),c(6)-bis(4-fluorophenyl)-3-methylpiperidin-4-one (abbreviated as CFMP). The CFMP was synthesized and analysed using FT-IR, 1H NMR, 13C NMR, and UV–Vis spectroscopy. Standard functional B3LYP/6–311++G(d,p) density functional theory (DFT) calculations were utilized for the CFMP compound. Molecular electrostatic potential, non-linear optical, and natural bond orbital studies were performed. The charge transfer inside the molecule was demonstrated using HOMO-LUMO energy calculations and Mulliken atomic charges. The vibrational frequency was computed using the DFT/B3LYP/6–311++G(d,p) method. The non-covalent interactions were investigated using the Hirshfeld surface analysis. Furthermore, molecular docking was studied to discover novel inhibitors and drugs in treating Alzheimer's diseases. Further, docking studies were performed to predict and describe the interactions of four proteins with the ligand. This result demonstrates that the CFMP has an inhibitor effect against Alzheimer's diseases.

The physicochemical properties of binary systems are of great importance for the application of the latter. We report on the investigation of an ammonium sulfamate–urea binary system with different component ratios using a combination of experimental (FTIR, XRD, TGA/DSC, and melting point) and theoretical (DFT, QTAIM, ELF, RDG, ADMP, etc.) techniques. It is shown that, at a temperature of 100 °C, the system under study remains thermally and chemically stable for up to 30 min. It was established using X-ray diffraction analysis that the heating time barely affects the X-ray characteristics of the system. Data on the aggregate states in specified temperature ranges were obtained with thermal analysis and determination of the melting point. The structures of the ammonium sulfamate–urea system with different component ratios were optimized within the density functional theory. The atom-centered density matrix propagation calculation of the ammonium sulfamate–urea system with different component ratios was performed at temperatures of 100, 300, and 500 K. Regardless of the component ratio, a regular increase in the potential energy variation (curve amplitude) with an increase in temperature from 100 to 500 K was found.

Imidazole derivatives have found wide application in organic and medicinal chemistry. In particular, benzimidazoles have proven biological activity as antiviral, antimicrobial, and antitumor agents. In this work, we experimentally and theoretically investigated N-Butyl-1H-benzimidazole. It has been shown that the presence of a butyl substituent in the N position does not significantly affect the conjugation and structural organization of benzimidazole. The optimized molecular parameters were performed by the DFT/B3LYP method with 6-311++G(d,p) basis set. This level of theory shows excellent concurrence with the experimental data. The non-covalent interactions that existed within our compound N-Butyl-1H-benzimidazole were also analyzed by the AIM, RDG, ELF, and LOL topological methods. The color shades of the ELF and LOL maps confirm the presence of bonding and non-bonding electrons in N-Butyl-1H-benzimidazole. From DFT calculations, various methods such as molecular electrostatic potential (MEP), Fukui functions, Mulliken atomic charges, and frontier molecular orbital (HOMO-LUMO) were characterized. Furthermore, UV-Vis absorption and natural bond orbital (NBO) analysis were calculated. It is shown that the experimental and theoretical spectra of N-Butyl-1H-benzimidazole have a peak at 248 nm; in addition, the experimental spectrum has a peak near 295 nm. The NBO method shows that the delocalization of the aσ-electron from σ (C1–C2) is distributed into antibonding σ* (C1–C6), σ* (C1–N26), and σ* (C6–H11), which leads to stabilization energies of 4.63, 0.86, and 2.42 KJ/mol, respectively. Spectroscopic investigations of N-Butyl-1H-benzimidazole were carried out experimentally and theoretically to find FTIR vibrational spectra.

In this research, the impact of non-covalent interactions on the FT-IR spectrum and structural, electronic, topological and vibrational properties of hybrid 4-methylbenzylammonium nitrate (4MBN) have been studied combining B3LYP/CC-PVTZ calculations with molecular docking. 4MBN was synthesized and characterized by using the FT-IR spectrum while the optimized structures in gas phase and in ethanol and aqueous solutions have evidenced monodentate coordination between the nitrate and methylbenzylammonium groups, in agreement with that experimental determined for this species by X-ray diffraction. Here, non-covalent interactions were deeply analyzed in terms of topological parameters (AIM), electron localization function (ELF), localized orbital locator (LOL), Hirshfeld surface and reduced density gradient (RDG) method. Weak interactions such as H-bonds, VDW and steric effect in 4MBN were visualized and quantified by the independent gradient density (IGM) based on the promolecular density. The hyper-conjugative and the delocalization of charge in 4MBN have been elucidated by natural bonding orbital (NBO) while its chemical reactivity was studied and discussed by using molecular electrostatic potential surface (MESP), frontier molecular orbital (FMOs), density of state (DOS) and partial density of state (PDOS). The complete vibrational assignments of 69 vibration modes expected for 4MBN are reported together with the scaled force constants while the electronic transitions were evaluated by TD-DFT calculations in ethanol solution. Thermal analysis (DTA and DSC) was also determined. Molecular docking calculations have suggested that 4MBN presents biological activity and could act as a good inhibitor against schizophrenia disease.

Piperidine pharmacophore-containing compounds have demonstrated therapeutic efficacy against a range of diseases and are now being investigated in cancer. A series of 3-chloro-3-methyl-2,6-diarylpiperidin-4-ones, compounds (I–V) were designed and synthesized for their evaluation as a potential anti-cancer agent. Compounds II and IV reduced the growth of numerous hematological cancer cell lines while simultaneously increasing the mRNA expression of apoptosis-promoting genes, p53 and Bax. Molecular docking analyses confirmed that compounds can bind to 6FS1, 6FSO (myeloma), 6TJU (leukemia), 5N21, and 1OLL (NKTL). Computational ADMET research confirmed the essential physicochemical, pharmacokinetic, and drug-like characteristics of compounds (I–V). The results revealed that these compounds interact efficiently with active site residues and that compounds (II) and (V) can be further evaluated as potential therapeutic candidates.

Structure−activity relationships for hydroxychloroquine compound and its derivatives resulted in a potent antiviral activity. Where hydroxychloroquine derivatives showed an apparent efficacy against coronavirus related pneumonia. For this reason, the current study is focused on the structural properties of hydroxychloroquine and hydroxychloroquine sulfate. Optimized structures of these molecules have been reported by using DFT method at B3LYP/6-31G* level of theory. The geometric were determined and compared with the experimental crystal structure. The intra and intermolecular interactions which exist within these compounds are analyzed by different methods namely the topological analysis AIM, ELF and the reduced gradient of the density. These approaches make it possible in particular to study the properties of hydrogen bonds. The highest occupied molecular orbital and the lowest unoccupied molecular orbital energy levels are constructed and the corresponding frontier energy gaps are determined to realize the charge transfer within the molecule. The densities of state diagrams were determined to calculate contributions to the molecular orbitals. The molecular electrostatic potential surfaces are determined to give a visual representation of charge distribution of these ligands and to provide information linked to electrophilic and nucleophilic sites localization. Finally, these derivatives were evaluated for the inhibition of COVID-19 activity by using the molecular docking method.

This work is devoted to investigating the molecular geometry, biological activities, electronic and vibrational characteristics of 1-phenylpiperazin-1,4-diium nitrate monohydrate (1PPNO3) by combining quantum chemical calculations with molecular docking. The geometric structure has been optimized with the Density functional theory (DFT) method using B3LYP-D and WB97XD functional. By referring to the values of the RMSD, the DFT calculation reproduces well the bonds lengths and the angles. Atoms-in-molecules, reduced density gradient and electron localization function analyses have been carried out to study the intra and intermolecular interactions within molecule, in particular to study the properties of hydrogen bonds. NBO orbital analysis has been reported to study electronic exchanges and transfer reactions between donor and acceptor compounds. In addition, Hirshfeld Surface Analysis (HS) was evaluated in order to discern the interactions in the crystal structure. The molecular electrostatic potential was calculated to identify the electrophilic and nucleophilic sites which favor the formation of hydrogen bonds. Inhibitor characteristics of 1PPNO3 on Kalirin-7 and monoamine oxidase B enzymes with several selective inhibitors were examined by molecular docking. Finally, thermal (DTA) and thermogravimetric (TG) analyses for the title compound have been conducted and the thermodynamic properties were determined via model chemistry.

The recently emerged COVID-19 virus caused hundreds of thousands of deaths and instigated a widespread fear, threatening the world’s most advanced health security. In 2020, chloroquine derivatives are among the drugs tested against the coronavirus pandemic and showed an apparent efficacy. In the present work, the chloroquine and the chloroquine phosphate molecules have been proposed as potential antiviral for the treatment of COVID-19 diseases combining DFT and molecular docking calculations. Molecular geometries, electronic properties and molecular electrostatic potential were investigated using density functional theory (DFT) at the B3LYP/6-31G* method. As results, we found a good agreement between the theoretical and the experimental geometrical parameters (bond lengths and bond angles). The frontier orbitals analysis has been calculated at the same level of theory to determine the charge transfer within the molecule. In order to perform a better description of the FMOs, the density of states was determined. The molecular electrostatic potential maps were calculated to provide information on the chemical reactivity of molecule and also to describe the intermolecular interactions. All these studies help us a lot in determining the reactivity of the mentioned compounds. Finally, docking calculations were carried out to determine the pharmaceutical activities of the chloroquine derivatives against coronavirus diseases. The choice of these ligands was based on their antiviral activities.

In the present work, the succinic acid (SA), L-pyroglutamic acid (L-PGA), N-phenyl-thioacetamide (N-NPTA), 2-amino-5-chloropyridine hydrogen succinate (ACPS), epigallocatechine Gallate (EGCG) or KDH and, selenomethionine (SeM) compounds have been proposed as potential antiviral candidates to treatment of COVID-19 based on B3LYP/6-311++G∗∗ calculations and molecular docking. Solvation energies, stabilization energies, topological properties have been evaluated as function of acceptors and donors groups present in their structures. ACPS presents the higher reactivity in solution possibly because has the higher nucleophilicity and elecrophilicity indexes while KDH evidence the higher solvation energy probably due to the higher quantity of donors and acceptors groups. NBO studies show that KDH is the most stable in solution. Mapped MEP surfaces have evidenced stronger nucleophilic and electrophilic sites in ACPS, in agreement with the three C=O and two N–H and O–H groups present in this species while KDH has only a C=O group but a total of 19 acceptors and donors groups. From the above studies for six species we can propose that the better potential antiviral candidate to treatment of COVID-19 is ACPS and then, KDH. For a better prediction of the antiviral and anti-inflammatory properties of the proposed compounds, molecular docking calculations were performed by using four structures of COVID-19. Docking results were discussed basing on binding affinities and the interaction types among ligands and different amino acid residues, indicating the powerful ability of KDH and then ACPS ligands on front of the novel coronavirus disease especially for the first and the fourth species (6LU7, 7BTF).

Spruce (Piceaabies) wood hemicelluloses have been obtained by the noncatalytic and catalytic oxidative delignification in the acetic acid-water-hydrogen peroxide medium in a processing time of 3–4 h and temperatures of 90–100 °C. In the catalytic process, the H2SO4, MnSO4, TiO2, and (NH4)6Mo7O24 catalysts have been used. A polysaccharide yield of up to 11.7 wt% has been found. The hemicellulose composition and structure have been studied by a complex of physicochemical methods, including gas and gel permeation chromatography, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. The galactose:mannose:glucose:arabinose:xylose monomeric units in a ratio of 5:3:2:1:1 have been identified in the hemicelluloses by gas chromatography. Using gel permeation chromatography, the weight average molar mass Mw of hemicelluloses has been found to attain 47,654 g/mol in noncatalytic delignification and up to 42,793 g/mol in catalytic delignification. Based on the same technique, a method for determining the α and k parameters of the Mark–Kuhn–Houwink equation for hemicelluloses has been developed; it has been established that these parameters change between 0.33–1.01 and 1.57–472.17, respectively, depending on the catalyst concentration and process temperature and time. Moreover, the FTIR spectra of the hemicellulose samples contain all the bands characteristic of heteropolysaccharides, specifically, 1069 cm−1 (C–O–C and C–O–H), 1738 cm−1 (ester C=O), 1375 cm−1 (–C–CH3), 1243 cm−1 (–C–O–), etc. It has been determined by the thermogravimetric analysis that the hemicelluloses isolated from spruce wood are resistant to heating to temperatures of up to ~100 °C and, upon further heating, start destructing at an increasing rate. The antioxidant activity of the hemicelluloses has been examined using the compounds simulating the 2,2-diphenyl-2-picrylhydrazyl free radicals.

Xanthan is an important polysaccharide with many beneficial properties. Sulfated xanthan derivatives have anticoagulant and antithrombotic activity. This work proposes a new method for the synthesis of xanthan sulfates using sulfamic acid. Various N-substituted ureas have been investigated as process activators. It was found that urea has the greatest activating ability. BBD of xanthan sulfation process with sulfamic acid in 1,4-dioxane has been carried out. It was shown that the optimal conditions for the sulfation of xanthan (13.1 wt% sulfur content) are: the amount of sulfating complex per 1 g of xanthan is 3.5 mmol, temperature 90 °C, duration 2.3 h. Sulfated xanthan with the maximum sulfur content was analyzed by physicochemical methods. Thus, in the FTIR spectrum of xanthan sulfate, in comparison with the initial xanthanum, absorption bands appear at 1247 cm−1, which corresponds to the vibrations of the sulfate group. It was shown by GPC chromatography that the starting xanthan gum has a bimodal molecular weight distribution of particles, including a high molecular weight fraction with Mw > 1000 kDa and an LMW fraction with Mw < 600 kDa. It was found that the Mw of sulfated xanthan gum has a lower value (~612 kDa) in comparison with the original xanthan gum, and a narrower molecular weight distribution and is characterized by lower PD values. It was shown by thermal analysis that the main decomposition of xanthan sulfate, in contrast to the initial xanthan, occurs in two stages. The DTG curve has two pronounced peaks, with maxima at 226 and 286 °C.

The process of sulfation of arabinogalactan—a natural polysaccharide from Larix sibirica Ledeb.—with sulfamic acid in 1,4-dioxane using different activators has been studied for the first time. The dynamics of the molecular weight of sulfated arabinogalactan upon variation in the temperature and time of sulfation of arabinogalactan with sulfamic acid in 1,4-dioxane has been investigated. It has been found that, as the sulfation time increases from 10 to 90 min, the molecular weights of the reaction products grow due to the introduction of sulfate groups without significant destruction of the initial polymer and sulfation products. Sulfation at 95 °C for 20 min yields the products with a higher molecular weight than in the case of sulfation at 85 °C, which is related to an increase in the sulfation rate; however, during the further process occurring under these conditions, sulfation is accompanied by the destruction and the molecular weight of the sulfated polymer decreases. The numerical optimization of arabinogalactan sulfation process has been performed. It has been shown that the optimal parameters for obtaining a product with a high sulfur content are a sulfamic acid amount of 20 mmol per 1 g of arabinogalactan, a process temperature of 85 °C, and a process time of 2.5 h.

A quantum theoretical approach, within the adiabatic approximation and taking into account a strong non-adiabatic correction via the resonant exchange between the fast mode excited states of the two moieties of the dimer. The intrinsic anharmonicity of the low-frequency mode through a Morse potential, direct and indirect damping, and a selection rule breaking mechanism for forbidden transitions, is applied to reproduce the υX-H IR line shape of cyclic dimers of moderately H-bonded species in the crystalline phase. The results are used to gain an insight into the experimental spectral line shapes obtained by the transmission method. This approach fits satisfactorily the experimental line shape of 2-thiopheneacetic acid and predicts their evolution with isotopic substitution. Numerical calculations show that mixing of all these effects allows one to reproduce the main features of the experimental IR line shapes.