Structural, elastic, electronic and optical properties of zinc-chalcogenides (viz. ZnX, X = S, Se and Te) are studied in zinc-blende structure under hydrostatic pressure using the full-potential linearized augmented plane wave method. Generalized gradient approximation is used for exchange correlation potentials. Pressure-dependent lattice constants and bulk moduli are obtained using the optimization method. Young's modulus, Poisson's ratio, internal strain parameter and anisotropy are also calculated. The higher values of Young's modulus in comparison to the bulk modulus show that these materials are hard to break. Poisson's ratio is computed for the first time for these materials to the best of our knowledge and its values show higher ionic contribution in these materials. Modified Becke and Johnson (mBJ) method is used to study band gaps, density of states, dielectric function and refractive index. Electronic study shows direct band gaps convert to indirect band gaps with increasing pressure in the case of ZnS and ZnTe. We compared our results with other theoretical and experimental results. Our results are far better than other theoretical results because mBJ is the best technique to treat II–VI semiconductors.
Fungi and bacteria are a great threat to all living organisms by causing illnesses in them. Rate of spreading diseases by them is higher in contrast to synthesis of drugs that are antifungal and/or antibacterial 1-4. At present substantial part of the research in chemistry is devoted to the synthesis and characterization of biologically active compounds that would be used against the microbes 5-16. Monoesters of succinic acid, in addition to their chemical uses, possess medicinal properties like, antiHIV, antitumor, antiseptic, antioxidant, antifungal and antibacterial 10-16 activities. In continuation to our work to establish medicinal use of monoesters 17-20 twentyseven (1-27) new monoesters were prepared from succinic anhydride 7 and explored for antifungal and antibacterial activity. All the reported compounds displayed considerable bioactivities. However, the halogenated esters displayed activity equivalent to standard drugs chloramphenicol and ketoconazole. EXPERIMENTAL The microbes used for bioactivities of synthesized compounds (1-27) were Candida albicans ATCC 10231 (C. albicans), Aspergillus niger F2723 (A. niger), Escherichia coli MTCC-739 (E. coli) and Proteus mirabilis ATCC 14153 (P. mirabilis). Ketoconazole purchased from M/s SMS Pharmaceuticals Ltd. Hyderabad and chloramphenicol from Sigma St. Louis, USA was used as standard.
In the present study, pyrazole-thiophene-based amide derivatives were synthesized by different methodologies. Here, 5-Bromothiophene carboxylic acid (2) was reacted with substituted, unsubstituted, and protected pyrazole to synthesize the amide. It was observed that unsubstituted amide (5-bromo-N-(5-methyl-1H-pyrazol-3-yl)thiophene-2-carboxamide (7) was obtained at a good yield of about 68 percent. The unsubstituted amide (7) was arylated through Pd (0)-catalyzed Suzuki–Miyaura cross-coupling, in the presence of tripotassium phosphate (K3PO4) as a base, and with 1,4-dioxane as a solvent. Moderate to good yields (66–81%) of newly synthesized derivatives were obtained. The geometry of the synthesized compounds (9a–9h) and other physical properties, like non-linear optical (NLO) properties, nuclear magnetic resonance (NMR), and other chemical reactivity descriptors, including the chemical hardness, electronic chemical potential, ionization potential, electron affinity, and electrophilicity index have also been calculated for the synthesized compounds. In this study, DFT calculations have been used to investigate the electronic structure of the synthesized compounds and to compute their NMR data. It was also observed that the computed NMR data manifested significant agreement with the experimental NMR results. Furthermore, compound (9f) exhibits a better non-linear optical response compared to all other compounds in the series. Based on frontier molecular orbital (FMO) analysis and the reactivity descriptors, compounds (9c) and (9h) were predicted to be the most chemically reactive, while (9d) was estimated to be the most stable among the examined series of compounds.
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