Randeep Kaur

Zwitterionic liquid (ZIL) coated CuO as an efficient catalyst for the green synthesis of bis-coumarin derivatives via one-pot multi-component reactions using mechanochemistry

A convenient, solvent free strategy for the synthesis of bis-coumarins has been developed using zwitterionic liquid (ZIL) coated copper oxide (CuO) and mechanical ball milling. The ZIL were fabricated from imidazolium/benzimidazolium and sulfonate/carboxylate based moieties. Use of the ZIL offers an interesting multifunctional opportunity to immobilize them over CuO using the anionic part and the cationic part is left freely available for use in catalytic applications. The hybrid catalysts were fully characterized using scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, powder X-ray diffraction, cyclic voltammetry, solid state ultraviolet-visible absorption and spectroscopic emission methods. The three ZIL-based and CuO coupled hybrid catalysts (ZIL@CuO1–3) generated were found to have diverse sizes, shapes, photophysical signatures and electrochemical properties. The supramolecular assembly of ZIL and CuO in ZIL@CuO1 has extensively enhanced catalytic activity compared to their individual parent components as well as to the two other hybrid materials, ZIL@CuO2–3. The reaction conditions were optimized by varying the number of balls used, the milling time and the milling speed. The reaction mechanism was elucidated using proton–nuclear magnetic spectroscopy and all the final products were fully characterized using spectroscopic methods. Finally, the performance of the reaction at the multigram scale is also detailed and a high EcoScale score and a low E-factor are the most pleasing features of this methodology, and thus, authenticate its use for eco-friendly synthesis of bis-coumarins and offer advancements over other catalysts described in the literature.

Structural and magnetic characterization of Ti doped cobalt ferrite (CoFe2O4)

Synthesis of Co1-xTixFe2O4 solid solutions for 0.1≤x≤0.4 using the solid-state-reaction rate has been done. The prepared samples were characterized by using XRD (X-ray diffraction) and SEM (Scanning Electron Microscopy). Magnetic studies have been done using Vibrating Sample Magnetometer (VSM). XRD confirmed that Cobalt Ferrite spinel cubic structure in all prepared samples. The lattice parameter ‘a’ increases with increase in the concentration of Ti. SEM micrograph shows good grain growth in all samples. Magnetic Study reveals that the M-H curves of all the prepared samples taken at room temperature are very well saturated. The maximum value of remnant magnetization (Mr ∼13.9 emu/g) and saturation magnetization (Ms ∼74.4 emu/g) has been observed for x =0.2 sample. Coercivity does not show any regular variation with increase in the molar concentration of Ti in CoFe2O4 at A-site.Synthesis of Co1-xTixFe2O4 solid solutions for 0.1≤x≤0.4 using the solid-state-reaction rate has been done. The prepared samples were characterized by using XRD (X-ray diffraction) and SEM (Scanning Electron Microscopy). Magnetic studies have been done using Vibrating Sample Magnetometer (VSM). XRD confirmed that Cobalt Ferrite spinel cubic structure in all prepared samples. The lattice parameter ‘a’ increases with increase in the concentration of Ti. SEM micrograph shows good grain growth in all samples. Magnetic Study reveals that the M-H curves of all the prepared samples taken at room temperature are very well saturated. The maximum value of remnant magnetization (Mr ∼13.9 emu/g) and saturation magnetization (Ms ∼74.4 emu/g) has been observed for x =0.2 sample. Coercivity does not show any regular variation with increase in the molar concentration of Ti in CoFe2O4 at A-site.

Conductivity relaxation and oxygen vacancies-related electron hopping mechanism in Pb1-xLax/2Smx/2Ti1-xFexO3 solid solutions

ABSTRACT Polycrystalline samples of Pb1-xLax/2Smx/2Ti1-xFexO3 (x = 0.20 and 0.30) have been prepared by solid state reaction route. The electrical properties of synthesized samples have been investigated using complex impedance spectroscopy as a function of frequency (100 Hz–1 MHz) within the temperature range of (448–573 K). The fitting of the Nyquist plots reveals that both grain and grain boundary contribute to relaxation and the grain boundaries are more resistive and capacitive than the grains. Modulus analysis shows that relaxation in both the samples is of non-Debye type and temperature independent. The Jonscher`s power law fit to the ac conductivity data confirms that the conduction in the prepared samples is due to the hopping of charge carriers. Long range conductivity type of relaxation is found in both the samples.

Exploration of insecticidal potential of an alpha glucosidase enzyme inhibitor from an endophytic Exophiala spinifera

The present study aimed to isolate and screen endophytes from Trachyspermum ammi with the ability to inhibit alpha glucosidase enzyme and evaluate their insecticidal potential.

Effect of samarium and iron substitution on the structural and magnetic properties of BaZr0.05Ti0.95O3 ceramics

Samarium and Iron doped barium zirconate titanate (SF-BZT) ceramics with general formula (SmFeO3)x - (BaZr0.05Ti0.95O3)1−x (x = 0, 0.21, 0.22, 0.23) were prepared by solid state reaction route. X-Ray Diffraction revealed the proper phase formation and the profile matching with constant scale factor confirmed phase change from tetragonal to pseudo cubic with increase in samarium and iron content. The SEM micrographs show proper grain growth in samples. The magnetic data confirmed the presence of ferromagnetic character in the SF-BZT solid solutions.