No abstract

In this study, rapid, simple approach was applied for synthesis of silver nanoparticles by using Psidium guajava aqueous leaf extract. The plant extract acts as both reducing agent and capping agent. The green synthesized silver nanoparticles were characterized by using physic-chemical techniques viz, UV-Visible spectroscopy, Fourier Transform Infrared Spectrophotometer [FTIR], Particle size analyser and Scanning electron microscopy. UV-Visible spectrophotometer showed absorbance peak in the range of 419nm.The compounds responsible for silver ions and the functional groups present in plant extract were identified and investigated by FTIR technique. The characterization data reveals that the particles were in crystalline in nature with an average size of 62nm. The silver nanoparticles (Ag NPs) were rapidly synthesized using aqueous extract of guava leaf with AgNO3 solution within 15min at room temperature, without the involvement of any hazardous chemicals. Keywords: Nano particles, green synthesis, Silver,  Psidium guajava and reducing agents.

The objective of present study is to synthesize copper nanoparticles from Vitex negundo Linn., root bark extract as reducing and stabilizing agents. The synthesized nanoparticles were characterized by using UV-visible spectrophotometer, X-ray diffraction, FTIR, SEM and EDX. The results were shown that copper nanoparticles exhibited UV-visible absorption peak at around 550 nm. The XRD study confirmed that nanoparticles are crystalline in nature. In addition to these, FTIR was also used to analyze the various functional groups stabilized and protected the copper nanoparticles. The SEM results revealed that the copper nanoparticles are spherical, cubic and hexagonal in shape and having the particle size ranging from 40 to 60 nm. Catalytic activity of copper nanoparticles were studied in the Huisgen [3+2] cycloaddition of azides and alkynes to obtain 1,4-disubstituted 1,2,3-triazole at room temperature. Antibacterial profile revealed that the biopotent copper nanoparticles exhibited moderate to good activity against bacterial strains.

Plant mediated green synthesis of silver nanoparticles (AgNPs) was carried out with the plant extract of Vitex negundo Linn., a simple method without using harmful chemicals. Herein, a root bark extract is used as reducing and capping agent for synthesizing AgNPs from silver nitrate solution. The characterization of AgNPs were obtained by UV-visible spectrophotometer, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive spectroscopy. The results were confirmed the presence of silver nanoparticles with UV-visible absorption peak at around 433-443 nm and its crystalline nature by XRD analysis. The FTIR spectrum confirmed that the synthesized AgNPs are stabilized and protected by various functional groups of biomolecules in extract. The SEM morphology showed the triangular or spherical shape of AgNPs with the size in the range of 80-100 nm and EDS confirmed the presence of elemental silver in the sample. The catalytic activity of AgNPs was investigated in the synthesis of 5-substituted 1H-tetrazole. Furthermore, antibacterial profile showed that biopotent AgNPs exhibited moderate to good antibacterial activity.