Combined experimental and theoretical studies on the molecular structures, spectroscopy, and inhibitor activity of 3-(2-thienyl)acrylic acid through AIM, NBO,FT-IR, FT-Raman, UV and HOMO-LUMO analyses, and molecular docking

Synthesis, growth, optical, mechanical, thermal, dielectric, and SHG properties of Triethylaminium picrate (TEAP) single crystal for nonlinear optical applications

Triethylaminium picrate (TEAP) crystals were grown using the slow evaporation solution growth method at ambient (35 °C) temperature. Salt was synthesized from Picric acid, and Triethylamine and methanol was used as solvents. The solution was mixed at a 1:1 ratio and evaporated slowly, produced yellow colour single crystal of TEAP with an average dimension of 19 × 8 × 5 mm3. The structure of the compound was determined by single-crystal X-ray diffraction (SCXRD) study, which confirms that the crystal is belongs to Orthorhombic crystal system, and its crystallinity was confirmed by the Bragg peak in the powder X-ray diffraction pattern. The superamolecular characteristic of the TEAP was confirmed by the Hirshfield analysis. CHN elemental analysis confirmed the stoichiometry and chemical composition of the synthesized complex salts. FT-IR and Polarized Raman spectral analyses confirmed the presence of different functional groups in the complex. UV-vis-NIR study identified the optical transmission window and the lower (TEAP) cut-off wavelength. Vickers' microhardness analysis determined the mechanical stability of the grown crystal. Studies of dielectric and AC conductivity were analyzed as a function of frequency. The thermogravimetry (TG) and differential thermal analysis (DTA) techniques were used to investigate the thermal behaviour of the material. The Kurtz-Perry powder technique was used to analyze the crystal's nonlinear optical properties (NLO) and found that its SHG efficiency was 1.5 times higher than that of potassium dihydrogen phosphate (KDP). The results from the obtained characterizations conclude that the TEAP crystal could be useful for NLO applications.

Designing of bis-organosilanes as dual chemosensor for Sn(II) and Al(III) ions: Antibacterial activity and in silico molecular docking study

Here, in this article, we present the design and synthesis of 1,2,3-triazole allied Schiff base functionalized organosilanes 6(a-e) utilising single step approach. These compounds were further characterised using NMR (1H, 13C) and mass spectrometry. Furthermore, UV-Visible and fluorescence spectroscopy showed that compound 6a had a high selectivityto Sn(II) and Al(III) metal ions compared to other relevant metal ions with lowlimit of detection (LOD) values. Suppression of -C=N isomerization, constrained intramolecular charge transfer (ICT), and complexation with Sn(II)/Al(III) ions (Chelation Enhanced Fluorescence (CHEF)) results in probe 6a's enhanced turn on fluorescence toward the detection of Sn(II) and Al(III) ions. Probe 6a was a strong candidate for the detection of Sn(II) and Al(III) ions due to its selectivity, reversibility, and competitiveness. Since the detecting phenomenon can be reversed, the sensor 6a perfectly mimics the INHIBIT molecular logic gate. Also, computational study utilising DFT technique was used to shed light on the complexation mode of 6a with Sn(II) and Al(III) metal ions. The compound 6a's antibacterial activity has also been successfully tested against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. Additionally, the compound 6a was docked to the E. coli and S. aureus proteins, which exhibited excellent results with binding energies of -7.18 Kcal mol-1 and -7.05 Kcal mol-1, respectively. As both in-vitro and docking studies demonstrated anti-bacterial activity of the probe 6a, it may be anticipated that the probe has potential to serve as anti-bacterial drug in nearly future.

A three orders of magnitude increase in nonlinear optical response by external electric field on Cryptand[2.2.2] (C222) based alkaline earthides

A new series of alkaline earthides based on Cryptand [2.2.2] (C222) containing nine complexes is designed by carefully placing alkali metals and alkaline earth metals inside and outside the C222 complexant, respectively i.e., M1(C222)M2 (M1 = Li, Na, K; M2 = Be, Mg, Ca). The designed complexes are reasonably stable both electronically and thermodynamically, as revealed through their vertical ionization potentials (VIPs) and interaction energies, respectively. Moreover, the true alkaline earthide nature of the complexes is confirmed through NBO and FMO analyses showing the negative charges and HOMOs over the alkaline earth metals, respectively. The further validity of true earthide characteristic is represented graphically by the spectra of partial density of states (PDOS). HOMO-LUMO gaps of the compounds are also very small (from 2.23 to 2.83 eV) when compared with pure cage's (C222) H-L gap i.e., 5.63 eV. All these features award these complexes with very small values of transition energies (ΔE) ranging from 0.68 to 2.06 eV ultimately resulting in remarkably high hyperpolarizability values up to 2.7 × 10⁵ au (for Na⁺(C222)Mg^-). Furthermore, applying external electric field (EEF) on the complexes enhances hyperpolarizability further. A remarkable increase of 1000 folds has been seen when hyperpolarizability of K⁺(C222)Ca^- is calculated after EEF application i.e., from 8.79 × 10⁴ au to 2.48 × 10⁷ au; when subjected to 0.001 au external electric field.

Synthesis, characterization, and molecular modeling of phenylenediamine-phenylhydrazine-formaldehyde terpolymer (PPHF) as potent anti-inflammatory agent

Inflammation, a characteristic physiological response to infections and tissue damage, commences with processes involving tissue repair and pathogen elimination, contributing to the restoration of homeostasis at affected sites. Hence, this study presents a comprehensive analysis addressing diverse aspects associated with this phenomenon. The investigation encompasses the synthesis, spectral characterizations (FT-IR, ¹H NMR, and ¹³C NMR), and molecular modeling of p-phenylenediamine-phenylhydrazine-formaldehyde terpolymer (PPHF), a potent agent in promoting inflammation. To explore the reactivity, bonding nature, and spectroscopy, as well as perform molecular docking for in-silico biological evaluation, density functional theory (DFT) utilizing the def2svp/B3LYP-D3BJ method was employed. The results reveal significant biological activity of the tested compound in relation to anti-inflammatory proteins, specifically 6JD8, 5TKB, and 4CYF. Notably, upon interaction between PPHF and 6JD8, a binding affinity of -4.5 kcal/mol was observed. Likewise, the interaction with 5TKB demonstrated an affinity of -7.8 kcal/mol. Furthermore, a bonding affinity of -8.1 kcal/mol was observed for the interaction with 4CYF. Importantly, these values closely correspond to those obtained from the interaction between the proteins and the standard drug ibuprofen (IBF), which exhibited binding affinities of -5.9 kcal/mol, -7.0 kcal/mol, and -6.1 kcal/mol, respectively. Thus, these results provide compelling evidence affirming the tremendous potential of p-phenylenediamine-phenylhydrazine-formaldehyde (PPHF) as a highly promising anti-inflammatory agent, owing to the presence of nitrogen-a heteroatom within the compound.

Computational modeling of imines based anti-oxidant and anti-esterases compounds: Synthesis, single crystal and In-vitro assessment

Molecular modeling strategy was adopted to check the biological potential of the imine based molecules against free radical, acetylcholine esterase and butyrylcholine esterase. Three Schiff based compounds as (E)-2-(((4-bromophenyl)imino)methyl)-4-methylphenol (1), (E)-2-(((3-fluorophenyl)imino)methyl)-4-methylphenol (2) and (2E,2E)-2-(2-(2-hydroxy-5-methylbenzylidene)hydrazono)-1,2-diphenylethanone (3) were synthesized with high yield. The synthesized compounds were characterized with the help of modern techniques such as UV, FTIR and NMR while exact structure was depicted with Single Crystal X-Ray diffraction technique which disclosed that compound 1 is orthorhombic, while 2 and 3 are monoclinic. A hybrid functional (B3LYP) method with general basis set of 6-31 G(d,p) were applied to optimize synthesized Schiff bases. The contribution of in-between molecular contacts within a crystalline assembly of compounds were studied using Hirshfeld surface analysis (HS). In order to check the ability of the synthesized compounds toward free radical and enzyme inhibition, in vitro models were used to assess the radical scavenging and enzyme inhibition potential which depicted that compound 3 showed highest potential (57.43 ± 1.0%; DPPH, 75.09 ± 1.0%; AChE and 64.47 ± 1.0%; BChE). The ADMET assessments suggested the drug like properties of the synthesized compounds. It was concluded from results (in vitro and in silico) that synthesized compound have ability to cure the disorder related to free radical and enzyme inhibition. Compound 3 was shown to be the most active compared to other compounds.

DFT and molecular docking study of chloroquine derivatives as antiviral to coronavirus COVID-19

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.

Molecular structure, IR, Raman and UV-VIS spectra of 2-cyanothiophene and 3-cyanothiophene: A comparative quantum chemical investigation

Spectroscopic data which are needed for detection of new species in the interstellar medium (ISM) are missing for five- and six-membered ring substituted derivatives. In order to supplement the existing literature information, quantum chemical calculations, including geometrical optimizations, simulated IR, Raman and UV-VIS spectra were carried out for 2-cyanothiophene (2CNT) and 3-cyanothiophene (3CNT). Structures for these molecular species were calculated from M06-2X/6-31G(d,p) computed results in conjunction with corrections for systematic deficiencies of basis sets and empirical adjustments for some geometrical parameters. A complete description of IR and Raman spectra including IR frequency assignment and potential energy distribution (PED) analysis is provided. IR and Raman spectra for deuterated species and UV-VIS spectra for thiophene, 2CNT and 3CNT were analyzed. The present computed molecular data are expected to assist astro-scientists in the search of these species in the ISM.

Molecular docking studies, structural and spectroscopic properties of monomeric and dimeric species of benzofuran-carboxylic acids derivatives: DFT calculations and biological activities

Structural optimization, molecular docking analysis, electronic and vibrational properties have been investigated for the 1-benzofuran-2-carboxylic acid (2BF) and 1-benzofuran-3-carboxylic acid (3BF) using DFT/B3LYP/6-311++G(d,p) level of theory. The theoretical parameters have a very good consistency with the experimental ones. The weak intermolecular interactions were analyzed by different tool such as: Hirshfeld surfaces, topological analysis and natural bond orbital studies. The nonlinear optical properties have been investigated. Molecular electrostatic potential and frontier molecular orbitals (FMOs) analysis have been carried out to understand the reactivity of the molecule. In addition, TD-DFT calculation is initiated to simulate the UV-vis absorption spectrum and to determine several important electronic properties like HOMO-LUMO gap energy and electronic transitions. The complete vibrational assignments and the force constants were reported for monomer and dimers of both acids. The biological activities of the tow acids have been studied via molecular docking analysis. The later calculations prove that the studied acids have an inhibitor effect against cancer and microbial diseases.

Computational study of 3-thiophene acetic acid: Molecular docking, electronic and intermolecular interactions investigations

The present work undertakes the structural and electronic properties of 3-thiophene acetic acid (abbreviated as 3-TAA) monomer and dimer. DFT calculations were performed using B3LYP functional in combination with the aug-cc-pVTZ basis set. The optimized structural parameters were found to be in a good agreement with experimental molecular geometry. The stability of the crystal packing was ensured by OH⋯O, C-H⋯O and CH⋯S intermolecular interactions. All the Non covalent interactions were deeply studied in terms of their topological parameters, Hirshfeld surface (HS) analysis and reduced density gradient (RDG) analysis. The electronic properties of the investigated compound have been performed using time dependent density functional theory (TD-DFT) and discussed through its correspondant HOMO, LUMO and excitation energy values. Likewise, the reactivity of 3-TAA was discussed in terms of several thermodynamic parameters. In addition, the molecular electrostatic potential (MEP) surface has been performed and discussed in terms of color distribution. In addition, the natural bond orbital (NBO) analysis was used to investigate the electronic charge transfer into the molecule. Harmine, Clorgyline, Isatin, zonisamide and our title compound including are known with their competitive inhibitory activity on Human monoamine oxidase, commonly named MAO A and B. This enzyme is a critical enzyme in the degradative deamination of biogenic amines throughout the body. Thus, molecular docking behaviors of 3-TAA are computed and compared to the results found for Harmine, Clorgyline, Isatin, zonisamide ligands.