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Background: Small molecule compounds are docked into receptor binding sites and the binding affinity of the complex is calculated using the structure-based drug design technique. Precise and quick docking processes, as well as the capacity to examine binding geometries and interactions, are required for a full knowledge of the structural principles that influence the strength of a protein/ligand complex. The present work deals with in-silico molecular docking studies of some heterocyclic compounds such as benzoxazole, benzimidazole, imidazole and tetrazole against the EGFR tyrosine kinase receptor. Methodology: Molecular docking studies of some heterocyclic compounds such as benzoxazole, benzimidazole, imidazole and tetrazole against the EGFR tyrosine kinase receptor using Schrodinger LLC (Maestro 9.2) software. Results: Our in silico observations reveal that, all the selected heterocyclic compounds (1-8) show good binding interaction and good docking score against selected target enzyme. Out of eight compounds selected for the study two compounds compound 3 and 7 shows higher glide score. Compound 3 binded to ASP855 with a docking score of −11.20 kcal/mol. Compound 7 binded to ASP855 with a docking score of −11.56kcal/mol. Conclusion: Docking results revealed that compounds (1-8) interact with EGFR kinase receptor active site. Among the compounds, compound 7 has shown the highest glide score of -11.56 kcal/mol.

Benzoxazole compounds have an important and broad range of biological activities. The benzoxazole and its substituted derivatives possess antimicrobial, antitumor, anti-inflammatory, antihistaminic, anti-parasitic, herbicidal, anti-allergic, anti-helmintic, anti-tubercular, anticonvulsant, hypoglycaemic, HIV-1 reverse transcriptase inhibitor and insecticidal activities. It has also been shown to have a binding affinity to Aβ42 fibrils. Such complex biological uses of benzoxazole compounds have inspired new efforts to find new derivatives with improved biological activity and different applications in the pharmaceutical industry. Due to outstanding relevance of this structure, the purpose of this analysis is to highlight aspects published in recent years (2000-2020) on the chemistry and biological activity of benzoxazoles.

Accessibility of adequate safe and fresh water for human consumption is one of the most significant issues throughout the world and extensive research is being undertaken to resolve it. Nanotechnology is now an outstanding medium for water treatment and remediation from microorganisms and organic dyes, as compared to conventional treatment methods. For this task graphitic carbon nitride (g-C3N4) is a potential nanomaterial for environmental remediation, but its photogenerated charge carrier recombination rate restricts its use in practical applications. Hence, in the current study, we used a simple one-step calcination method to synthesize various ratios of ZnO/g-C3N4 binary nanocomposites. The band gap of g-C3N4 is 2.70 eV, but it is shifted to 2.60 eV by the 0.75 : 1 ZnO/g-C3N4 binary nanocomposite. Moreover, phase structure, morphology, thermal stability, oxidation state, elemental analysis, and surface area were evaluated using XRD, SEM, TEM, TGA, XPS, and BET analysis. The optimal ZnO loading content was determined and the mechanism of enhanced photocatalytic activity was studied in detail. The photocatalytic efficiency of the best catalyst was employed for the degradation of textile effluent followed by phytotoxicity evaluation using methylene blue (MB), and rhodamine B (RhB) as a model substrate was tested. Furthermore, the textile effluent treatment analysis discovered that the 75 mg concentration of 0.75 : 1 ZnO/g-C3N4 catalyst degraded up to 80% within 120 min and significantly reduced the concentrations of different physico-chemical parameters of textile effluents. These treated effluents have no phytotoxic effects on fenugreek plants, according to a pot study. It was found that the mesoporous 0.75 : 1 ZnO/g-C3N4 catalyst can be used as an effective and low-cost technique for the degradation of azo dyes in textile wastewaters.

Accessibility of adequate safe and fresh water for human consumption is one of the most significant issues throughout the world and extensive research is being undertaken to resolve it. Nanotechnology is now an outstanding medium for water treatment and remediation from microorganisms and organic dyes, as compared to conventional treatment methods. For this task graphitic carbon nitride (g-C

2,4-Dimorpholino-4-yl-6-(4-nitrophenoxy)-[1,3,5]-triazine (DMNT) was synthesized and the molecular structure and vibrational frequencies were studied by density functional theory (DFT) method. The functional used was Becke’s three parameter exchange functional combined with the Lee-Yang-Parr correlation (B3LYP) and the standard basis set was 6-31G(d) for all atoms. The Fourier Transform-Infra Red (FT-IR) and FT-Raman spectra of DMNT were recorded and complete assignments of the observed vibrational frequencies are done. The assignments were confirmed by isotopic labelling. The structural parameters, harmonic vibrational frequencies, IR intensities and Raman intensities of DMNT in the ground-state were also computed. Non-linear optical behaviour of DMNT was analysed by examining the properties like electric dipole moment, polarizability and hyperpolarizability. Molecular properties such as ionization potential, electro-negativity, chemical potential and chemical hardness were obtained from molecular orbital analysis. Hyper conjugative interaction and charge delocalization taking place in DMNT was confirmed by Natural bond analysis studies. UV-Vis spectrum of DMNT was also recorded to understand the electronic properties. Graphical Abstract

Bismuth based nanoparticles (BBNs)exhibit immense potential due to unique physico chemical properties, therefore extensively applied in diverse technologies. On this account, a great deal of attention is being devoted to green synthesizing BBNs, which is an environmentally safe process, non-toxic, and stable, with a wide range of nanoscale production options. This review emphasizes the importance of green approaches for synthesizing BBNsusing bio extracts derived from plants and microorganisms. The selection of precursors, reducing agents, coating agents, solvents, quantity evaluation, and experimental conditions are all discussed in this review elaborately. Also,a consolidative account ona diverse range of applications of BBNsisbeing highlighted, along with recent breakthroughs of green synthetic technology based onthe knowledge of mechanism routes that have been available in the recent literature. Since review articles are often central points for beginners, this report leads readers to the articles that highlight the noteworthy advancement in the field of BBNs research. The goals of this study are to (i) outline advanced bismuth-based compounds that have been used to date, (ii) describe drawbacks in synthetic strategy and possible solutions, and (iii) make recommendations for future research.

The Fourier-transform infrared spectroscopy (FT-IR) spectrum of 2,4-dichloro-N-phenethylbenzenesulfonamide (DPBS) was obtained and the compound was studied theoretically. The optimized geometry, total electronic energy and vibrational wavenumbers of DPBS were examined using Hartree–Fock (HF) and density functional theory (DFT) method such as B3LYP, BP86 and M06 functionals with the basis set of 6-311++G(d,p) for all atoms. A complete vibrational assignment was studied for DPBS. The molecular orbital energies, polarizability and thermodynamic properties of DPBS were also computed. Analysis of molecular orbitals reveals the parameters such as chemical potential, chemical hardness and electrophilicity index. The molecular properties such as electric dipole moment µ, polarizability α, and hyperpolarizability β reveal the non-linear optical (NLO) property of DPBS. Natural bond analysis study reveals charge delocalization of the molecule. The experimental and computational results are found to have good agreement among themselves. The results of this work will pave the way for further insight in the study of the applications of DPBS.Graphical Abstract

Green synthesis approaches are gaining the attention of researchers and they follow a less hazardous process to obtain nanoparticles. Green synthetic methods are currently used in industry than other physicochemical methods. The magnesium oxide (MgO) nanoparticles have been effectively produced by green synthesis which is environmental friendly, non-toxic with greater stability and has broad range of opportunities for the production of this material in the nanoscale. But still some challenges have been raised for the production of same nanoparticles with huge amount by green synthesis approaches. This is because the biological extracts during the synthesis creates a barrier onto the elucidation of the reactions and their mechanisms. Therefore, this review deals the summing up of variety of biological substrates and different methodologies that can be utilized for the green synthesis of magnesium oxide nanoparticles with impact on their properties. This article also explains the mechanism routes reported in various literatures for better understanding. The energy and environmental applications of the MgO nanoparticles are also dealt with in this article.

A novel amino acid stabilized composite ZnS/CuS photocatalyst working under visible light was successfully prepared by a co-precipitation method. The ZnS/CuS nanocomposites with different mole ratios were synthesized and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy and transmission electron microscopy. Absorption ranges and band gap energies, which correspond to photocatalytic behavior, were investigated by UV–Vis spectroscopy. The photocatalytic activities of ZnS/CuS nanocomposites were evaluated against the degradation of an organic dye, methylene blue, under UV light and a blue emitting LED. In this study, visible light driven photocatalysis was designed based on photo-induced direct interfacial charge transfer introduced through the modification of ZnS with CuS nanoparticles. The obtained ZnS/CuS nanocomposites exhibited excellent photocatalytic activity and good reusability compared with pure ZnS nanoparticles. Results clearly showed that the ZnS/CuS nanocomposite at a 4:1 mol ratio exhibited the highest photocatalytic activity indicated by the degradation of methylene blue under UV and visible light.

The reduced graphene oxide (RGO) sheets (1–4 wt %) containing ZnO hexagonal hollow rods (GZC) nanocomposites were fabricated via sonochemical method. The synthesized composites were characterized using Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (UV-vis-DRS), Raman spectroscopy, thermo gravimetric analysis (TGA), field-emission scanning electron microscopy (FE-SEM), energy dispersive analysis of X-rays (EDX), high resolution transmission electron microscopy (HRTEM) and electrochemical impedance spectroscopy. The formation of hexagonal hollow ZnO rod was discussed with growth mechanism and their morphology was confirmed with FESEM and HRTEM analysis. The visible light driven photocatalytic activity of pure ZnO and an incorporation of varying weight percentages of GO into ZnO catalyst (GZC) were evaluated by using the methyl orange (MO) and methylene blue (MB) aqueous dye solutions as model organic pollutants. Among the developed nanocomposites, 3 wt% GZC nanocomposites possesses the highest degradation efficiency, that is, 90.72, 89.72% at 180, 240 min for MB and MO respectively with enhanced visible light absorption range.

2-(4-Bromophenyl)-3-(4-hydroxyphenyl)-1,3-thiazolidin-4-one and its selenium analogue were studied in the gas phase using HF and DFT methods. The functionals considered were B3LYP, BP86 and M06. The basis set for all the atoms was 6-311++ G(d,p). Molecular parameters such as bond lengths, bond angles, rotational constants, dipole moments, electronic energies, and vibrational parameters namely harmonic vibrational frequencies and relative intensities were computed for these compounds. Atomization energies, HOMO-LUMO gaps and natural charges on the atoms were also calculated. The molecular parameters and the vibrational spectra of sulfur compound are in good agreement with the experimental data. Therefore, the data for the selenium analogue should be helpful in its future characterization.

Review: literature data on the synthesis and biological activities of benzimidazoles dring the past few years 2000-2013; 82 refs.

Water dispersible Zn(1−x)MnxS solid solution photocatalysts stabilized with l -aspartic acid were synthesized by coprecipitation. Their photocatalytic activity was evaluated using methylene blue as a model pollutant. X-ray diffraction and Raman spectroscopy indicated the catalysts had a cubic crystal structure. The gradual increase in zinc sulphide (ZnS) lattice constant with increasing Mn2+ dopant concentration was due to the high ionic radius of Mn2+. Raman spectra exhibited two peaks at 260 and 345 cm−1. Ultraviolet–visible absorption spectra of the catalysts exhibited a strong excitonic peak at 270 nm, which was blue shifted compared with that of bulk ZnS (340 nm). This was attributed to quantum confinement and coupling effects. The hydrophilic l -aspartic acid on the photocatalyst surface had a positive effect on photocatalytic activity. The effects of dye and dopant concentrations on photocatalytic activity were investigated.

Review: literature data on the synthesis and biological activities of benzimidazoles dring the past few years 2000-2013; 82 refs.

Wurtzite type ZnS with flower-like hierarchical morphology has been synthesised at low temperature by wet chemical route using l -threonine as a surface modifying and morphology directing agent. X-ray diffraction studies indicate the formation of wurtzite crystal structure of ZnS. Transmission electron microscopy analysis indicates the self-assembly of small ZnS nanoparticles of size 5–8 nm to form flower like nanostructures of diameter 300 nm. Fourier transform infrared spectrum confirms the presence of l -threonine. Optical absorption studies reveal the presence of coupling effect in addition to the quantum confinement effect in these hierarchical nanostructures. Photoluminescence spectrum on deconvolution exhibits two Gaussian peaks centred at 486 nm and 554 nm indicating the presence of defects.