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A series of new pyrazolo[1,5‐a]pyrimidine 4–15 derivatives were synthesized starting from 3,5‐diaminopyrazole derivatives 3 a,b as precursor using a simple, efficient procedure, and screened for their in‐vitro antimicrobial activities. All the synthesized compounds were fully characterized by IR, 1HNMR, 13CNMR, MS spectral data, and elemental analysis. Among the investigated against the antimicrobial activity, compounds 4 b, 4 d, 4 e, 8 b, 9 and 12 showed the best activity. The remaining compounds were found to have weak activity against gram‐positive and gram‐negative. [ABSTRACT FROM AUTHOR]

Novel nanocomposites of polypyrrole (PPy) embedded in silica (SiO2) and iron phosphorus trisulphide (FePS3) nanoparticles have been fabricated. The nanocomposite's dielectric characteristics have been examined in relation to temperature ranges of 25-200°C and frequency ranges of 0.1-7 MHz. Fourier-transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), scanning electron microscopy (SEM-EDX), transmission electron microscope (TEM), and dielectric measurements have all been used to evaluate the prepared nanocomposite. The monoclinic crystal structure of the prepared FePS3 and PPy/SiO2/FePS3 nanocomposite is confirmed by XRD, EDX, and TEM studies. The FePS3 is perfectly layered structure in the SEM image, and FePS3 and SiO2 particles are well intercalated, creating novel nanocomposites of two nanoparticle phases that served as a union network during the polymerization process. The IR spectrum shows that PPy is a dopant in the interlayer area of FePS3. The splitting major peak (570 cm-1) of FePS3 is visible at around 640 and 560 cm-1. The high AC conductivity values indicated that the combination of FePS3/SiO2 nano-matrix contains PPy at high packing densities and confirming the semiconducting properties of the nanocomposite to be used in several electronic applications. [ABSTRACT FROM AUTHOR]

The dielectric investigations of porous synthetic silica gel modified with polyaniline (PANI) and polyethylene glycol (PEG) polyblend at various concentrations are demonstrated in this paper. By using the chemical oxidative process to embed polyaniline (PANI) and polyethylene glycol (PEG) into a silica matrix, conducting gel nanocomposites were synthesized. For various dopant concentrations, the dielectric permittivity (ε′), D.C. conductivity (σdc), loss tangent (tanδ) and dielectric loss (ε″) were investigated. The samples were characterized using differential thermal analysis/thermogravimetric analysis, Fourier transform infrared spectroscopy and high‐resolution transmission electron microscopy. Depending on the co‐blend content, PANI‐PEG modified silica structures produce nanoparticles ranging in size from 9.9 to 48.1 nm. The variation of DC conductivity (σdc) with PANI/PEG content shows Maxwell‐Wagner Sillars (MWS) effect confirming the role of the conjugation and the structural order. [ABSTRACT FROM AUTHOR]