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Interaction of an oxadiazole derivative with Ag/Au/Cu and graphene quantum dots with different solvents is reported theoretically. The adsorption energy is maximum for Cu6 cluster and minimum for Ag6 cluster. The asymmetric charge redistribution between DPMO and M6s produces an improvement in dipole moment values. The decrease in energy gaps of complexes increased conductivity and metal clusters can be used as a drug sensor. The solvation energies are higher negative in solvent media than in the gaseous media, indicating an enhancement in solvent medium’s stability. Wavefunction studies show that there exist significant noncovalent interactions between metal clusters and oxadiazole that facilitates cluster formation. DPMO is found to form stable clusters with graphene which is evident from the enhancement of Raman activity of the system through SERS also enabling it for sensing DPMO in a mixture.

The recent COVID-19 virus caused hundreds of thousands of deaths and a widespread fear that threatened the health security in the world. Chloroquine derivatives are among the drugs tested against corona virus pandemic in 2020 and have shown an apparent effectiveness. In this work, tryptamine derivatives have been identified as antiviral for treatment of COVID-19 diseases combining DFT and molecular docking and their activity is compared with the 7-chloro-4-hydrazinoquinoline drug. Using density functional theory, molecular geometries and electronic properties have been investigated. The frontier orbitals analysis has been predicted to determine charge transfer within molecules. The density of states was determined to perform a better description of the FMOs. The molecular electrostatic potential maps have been calculated to provide details about the molecule’s chemical reactivity and also to explain intermolecular interactions. All these studies help us a great in determining biological activities of the compounds described. Finally docking calculations were performed using AutoDock and Patchdock servers to assess the tryptamine derivative’s therapeutic activities against corona virus diseases. [ FROM AUTHOR] Copyright of Polycyclic Aromatic Compounds is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all Abstracts.)

Future diagnostics and therapy applications are in part riding on the discovery and implementation of new optical techniques and strategies (which often derive from dyads) for example, prediction of features in surface-enhanced Raman spectroscopy requires the study of chromophore-chromophore interactions involve intermolecular forces, drug delivery, and photo mechanisms which are of great interest. New matches between chromophore systems (i.e. FRET), and π-delocalized surfaces are important to study. We explore low-molecular weight drug molecules and their interaction with the reporter material/surface of graphene. Bonding, charge transfer and orbital interactions for 2-amino-5-(1-methyl-5-nitro-2-imidazolyl)-1,3,4-thiadiazole (megazol or AMIT) on graphene were carried out. The graphene model substrate was monotonically/monatomically substituted (doped) with one neutral heteroatom (N/O/S/B) in place of one carbon center; chemical adsorption of AMIT is due to charge transfer from doped graphene to AMIT (DFT). Our AMIT-nanocluster studies show that the nanoclusters will act as a sensor component for the detection of drugs due to SERS. Our findings identified that the greater the energy of the charge transfer, the stronger the calculated chemical adsorption. Additionally, charge transfer is highest for the N-doped systems and least for pristine graphene, resulting in a stronger adsorption energy for N-doped graphene. Mulliken charge analysis of structures confirms enhancement found in QD-AMIT systems.Communicated by Ramaswamy H. Sarma.

Surface-enhanced Raman scattering is a tool for improving the Raman signal of biomolecules using nanosized metal substrates. Nanomaterials such as nanocages and nanoclusters find vast applications in sensing materials, adsorption and medical devices. The characterization sensing parameters of melamine with Al12/B12-N12/P12 nanocages were investigated using quantum chemical calculations. Charge transfer from melamine (Me) to nanocage is demonstrated by Mulliken charge and natural bond orbital analysis. Furthermore, the analysis of the highest occupied molecular orbital and lowest unoccupied molecular orbital give the localization of electron density. Adsorption energies of − 115.2221, − 119.0147, − 118.8001 and − 92.8714 kcal/mol are found for AlN-Me, AlP-Me, BN-Me and BP-Me clusters. The second hyperpolarizability of all nanocage-Me systems shows very large enhancement. Melamine adsorption over nanocages causes change in electronic properties resulting in Raman mode’s enhancement and variation in chemical properties. The nanocages are cationic and melamine is anionic.

Spectroscopic investigations of 1-phenyl -2,3-dimethyl-5-oxo-1,2-dihydro-1H-pyrazol-4-ammonium 2[(2-carboxyphenyl) disulfanyl]benzoate (PACB) reported experimentally and theoretically. NH-O interaction is observed and there is a very large downshift for NH-O stretching frequency. Reactive sites are identified from the chemical and electronic properties. For PACB the maximum repulsion was around H33, H55 and H57 atom. LOL shows red regions between C-C and blue around C atoms are surrounded by a delocalized electron cloud. The red ring is a hallmark of electron density depletion from the NCI plot due to electrostatic repulsion and its existences suggests that coordination sphere for PACB is minimally strained around the central ion. Atomic contact energy values and high score of the docking results obtained propose that, PACB may have inhibitory properties and have a significant function in pharmacological chemistry. Molecular dynamics simulation was performed to validate the stability of the title compound with the Bovine thrombin-activatable fibrinolysis inhibitor protein.Communicated by Ramaswamy H. Sarma.

Using nanosized metal substrates, surface-enhanced Raman scattering (SERS) is a tool for improving the Raman signal of biomolecules. For detection, SERS has gained much popularity and an important role in determining chemical composition. In the present study, SERS spectra of 2-methyl-4-(4-methylpiperazin-1-yl)-10H-thieno[2,3-b][1,5]benzodiazepine (olanzapine) (MPTB) were investigated on silver and silver-gold metal substrates (SERSitive, Warsaw, Poland) at different concentrations. Also, different chemical and electronic properties are investigated using DFT calculations. The ring and other functional modes in SERS change in frequency values with variations in intensity for all concentrations. The molecule is oriented in a tilted manner with respect to Ag and Ag-Au.

Impurity-related detection and certification cycle assumes significance in drug production and this study provides theoretical structural and spectral characterization of phenothiazine analogues, a...

Adsorption of the sorbic acid drug onto the surface of coronene/fullerene/fullerene like nanocages was investigated by theoretical calculations. Our results showed that the sorbic acid drug connects the nanoclusters through oxygen and hydrogen atoms. Due to the adsorption of the sorbic acid drug, there are significant changes in chemical descriptors and nonlinear optical properties. Energy gap values of all nanocluster systems are reduced, resulting in enhance in the conductivity of systems except for fullerene. All complex’s ultraviolet (UV) visible wavenumber is blue-shifted and especially for coronene and fullerene complex, the values are very high. The enhancement for different functional group wavenumbers in the Raman spectrum indicates that it is possible to make a nanocage sensor for the detection of these compounds using surface-enhanced Raman scattering (SERS). Docking gives good values of atomic contact energies and suitable for drug delivery.

The geometry, frontier molecular orbitals, chemical reactivity, vibrational, NBO analysis and molecular docking simulations of Ethyl −2-(4-propoxybenzylidene)-7-methyl-3-oxo-5-(4-benzyloxy phenyl)-...

Adsorption of 2,4,6-tribromoaniline (BA), 2,4,6-trifluoroaniline (FA) and 2,4,6-trichloroaniline (CA) onto the surface of coronene/fullerene/fullerene-like nanocages was investigated by theoretical...

In this study, solvent-assisted co-grinding method is used to form the cocrystal of 8-hydroxy quinoline-5-sulfonic acid (HQS) and 5-chloro-8-hydroxyquinoline (CHQ). In order to determine spectroscopic and electronic properties, the theoretical characterization has been carried out. Charge delocalization patterns and second-order perturbation energies of the most interacting orbitals have also been computed and predicted. Geometrical parameters are in agreement with reported values. Molecular electrostatic potential plot predicts the reactive sites and electropositive potential region is around the hydrogen atom bonded through the nitrogen atoms, negative potentials on oxygen atoms and phenyl rings. Molecular docking of the study of the HQS-CHQ molecule has been performed for the receptors, 3C52, 4IIT, 3QYD and 4FGY.

The performance of nanotubes (NT) of carbon (CC), aluminum-nitrogen (AlN), and boron-nitrogen (BN) as a sensor and nanocarrier for mercaptopurine (MCP) was investigated by means of a theoretical approach. The calculated negative values of adsorption energy showed the interaction and adsorption of MCP. HOMO and LUMO distributions were only found on the NT counter portion of the drug-nanotube not on MCP for AlN-NT and BN-NT while HOMO is over MCP and LUMO are over NT for CC-NT. The polarizability of MCP-NTs is greater than that of MCP. Raman wavenumbers of MCP are enhanced in NTs and hence NTs can act as a sensor for the detection of MCP. Solvent dependency on adsorption behavior is also presented in the manuscript, where we found that the AlN nanotube showed exceptionally high free energy of adsorption over other nanotubes in all solvent mediums. Solvation-free energies were also reported. Noncovalent interaction scattered plot also showed significant intermolecular interaction between AlN nanotubes and the mercaptopurine when compared to other nanotubes under study. To find the antiviral activity of MCP and MCP-NTs against antiviral activities, docking and molecular dynamics simulations were performed with 1HMP PDB. Recovery times show that MCP desorption occurs quickly. The MD simulations and docking results show that BN and CC-NTs with MCP show good activity as drug carriers.

Benzimidazole derivatives flubendazole (FD1) and similar derivatives, mebendazole (MD2) and ricobendazole (RD3) have been studied by using various computational tools to analyze their geometry and ...

1-[([1,1I-Biphenyl]-4-yl](phenyl)methyl]-1H-imidazolium-2,5-dichloro-3,6-dihydroxy-cyclohexa-2,5-diene-1,4-dione (BCAA) and 1-[([1,1I-Biphenyl]-4-yl](phenyl)methyl]-1H-imidazolium-4,5-dichloro-3,6-dioxocyclohexa-1,4-diene-1,2-dicarbonitrile (BDDQ) were synthesized and characterized using spectral analysis. The fundamental structural aspects of these derivatives have been examined based on optimized geometry, spectroscopic behavior, intermolecular interaction, chemical reactivity, and molecular docking analysis. The most stable minimum energy conformer of the title molecules was identified by potential energy surface scan along the rotational bonds. Accordingly, global and local chemical reactivity descriptors were investigated. The wavenumber downshift of different modes is noted. Title molecules exhibit inhibitory activity against different receptors.

Three aminobenzoate derivatives, benzocaine (B1), butamben (B2) and n-pentyl 4-aminobenzoate (B3) were analyzed for the structural, nonlinear optical, electronic and biological properties. The func...

The article highlights insights into biological activity using computational methods in products of 1,3,5-triazine-2,4-diamine with 1H-indole-2,3-dione (isatin)/(2E)-13-diphenylprop-2-en-1-one (chalcone)/10H-acridin-9-one (acridone). Biological activity is carried out using the method of electron density, 6-311++G(d,p) for molecular and electronic characteristics. Frontier molecular orbitals provide quantum mechanical descriptors to determine electronic properties. Studies show reduced energy gap with high kinetic stability and the index of electrophilicity is a consequence of delocalized sites of 1,3,5-triazine-2,4-diamine and nucleophilic sites are responsible for biological activity. Enhancement in electrophilicity index of products confirms electron acceptor between the reactants. The structural and molecular docking with different proteins shows that the product molecules are good drugs for the corresponding activity.

The Gaussian 09 DFT tool is used to investigate the formational electronic behaviour, reactivity analysis and biological properties of fluphenazine dihydrochloride (FDD). The quantum computation is used to determine the spectroscopic and vibrational assignments of FDD. The NBO method explains charge transfer and molecular interactions. Energy gap values are determined using FMO analysis in different solvents and toluene is a better solvent due to higher value of solvation energy. The UV-visible spectra are investigated in various solvents using the TD-DFT method. Electrostatic potential, the wave function related properties such as LOL, NCI and RDG are determined in gaseous phase. Furthermore, the drug likeness is analyzed. At last, a docking study with MD simulation is used to investigate FDD's antiviral activity against SARS-CoV-2 main protease.

This combined Al

The performance of nanotubes (NT) of carbon (CC), aluminium-nitrogen (AlN) and boron-nitrogen (BN) as a sensor and nanocarrier for mercaptopurine (MCP) was investigated by means of theoretical approach. The calculated negative values of adsorption energy showed the interaction and adsorption of the drug. HOMO and LUMO distributions were only found on the NT counter portion of drug-nanotube not on MCP for AlN-NT and BN-NT while HOMO is over MCP and LUMO is over NT for CC-NT. The polarizability of MCP-NTs is greater than that of MCP. Raman wavenumbers of MCP are enhanced in NTs and hence NTs can act as a sensor for detection of MCP. Solvent dependency on adsorption behavior is also presented in the manuscript, where we found that AlN nanotube showed exceptionally high free energy of adsorption over other nanotubes in all solvent medium. Solvation free energies were also reported. Non covalent interaction scattered plot also showed significant inter molecular interaction between AlN nanotubes and the mercaptopurine when compared to other nanotubes under study.

Using density functional theory, the adsorption of valproic acid onto the surface of fullerene-like nanocages was investigated. Valproic acid interact the nanocages through the carboxylic group with energies of -144.14, -109.71, -105.22 and -84.96 kcal/mol. The FMOs energy levels were considerably altered upon adsorption, resulting in a reduction in energy gap and increase in electrical conductivity. This suggests that nanocages could be used as sensors as well as options for drug administration in biological systems. Solvation effects in water are also reported.

Using density functional theory, the adsorption of valproic acid onto the surface of fullerene-like nanocages was investigated. Valproic acid interacts with the nanocages through the carboxylic group with energies of - 144.14, - 109.71, - 105.22, and - 84.96 kcal/mol. The frontier molecular orbital (FMO) energy levels were considerably altered upon adsorption, resulting in a reduction in energy gap and increase in electrical conductivity. This suggests that nanocages could be used as sensors as well as options for drug administration in biological systems. Solvation effects in water are also reported.

The spectroscopic, solvent effects, reactivity and MD simulations of N'-[(1E)-(2,6-dichlorophenyl-methylidene]adamantane-1-carbohydrazide (DMC) are reported. Solvation free energies of DMC in chloroform, ethanol and acetonitrile are −21.96, −24.39 and −12.31 kcal/mol and ethanol may be better for the solubilization. Electron donating and electron accepting powers are somewhat lower in solution, revealing a certain increase in the tendency to receiving electrons and a decrease in donate electrons in solution, except in acetonitrile, in which showed slightly higher values then in vacuum. ALIE surface show that regions where low energy is required to remove electrons are on benzene ring, chlorine atoms and N5. DMC is forming good contacts with protein's binding site residues and is important in the complex's stability showing antiviral activity.

The quantum chemical calculation of 9-methylanthracene and 2,3-dimethylanthracene molecules were carried out (9MA and 23DMA). The Density Functional Theory (DFT) by the method RB3LYP with the basis...

The first principle calculations were performed using the B3LYP/cc-pVDZ level to find the structural and geometrical parameters, vibrational wavenumbers and various molecular properties of three fl...

Theoretical calculations were done using density functional theory in order to determine vibrational frequencies, infrared and Raman intensities, MEP, NLO and NBO properties of the Hydrochlorothiazide-isoniazid (HCTA-IN) and Hydrochlorothiazide-malonamide (HCTA-MA) cocrystals. Electron donor-acceptor due to charge transfer mechanism has been scrutinized by the NBO investigation. First order hyperpolarizability of HCTA-IN and HCTA-MA are 19.86 and 7.80 times that of urea. The downshift of NH2, NH and C O modes are due to strong hyper conjugative interactions are indicated in NBO analysis. TD-DFT analysis was used to generate the theoretical electronic spectra, which shows a charge transfer process between the thiazide and isoniazid in HCTA-IN complex. Light harvesting efficiency studies reveal efficient photosensitization potential and photochemical modeling proves the efficiency of the cocrystal to be used in dye sensitized solar cells. Title compounds are docked with glucocorticoid receptor (1NHZ) and peroxidase manganese-dependent I (1YYD).