Articles

Articles

In this study, at first, the biosynthesis of silver nanoparticles (Ag NPs) using an aqueous extract of ThymbraspicataL wasstudied andthen, the shape and size ofthe synthesized NPs were characterized by different analysis such as UV-Vis, TEM, SEM, EDX, XRD, DLS and FT-IR. The synthesized Ag NPs were evaluated for their antibacterial activity against Escherichia coli (PTTC 1707), Staphylococcus aureus (PTTC 1112), Bacillus cereus (PTTC 1154) and Aspergillus Niger (PTTC 5012) and Candida albicans (PTTC5027) by a well-diffusion method and determination of minimum inhibitory concentration (MIC). Ag NPs displayed significant antimicrobial activity against the specimens, and they prevented the growth of bacteria and fungi at low concentrations.

Authors:Tayeb AB Matin, Nahid Ghasemi, Keivan Ghodrati, Majed Ramezani

Here, green synthesis of silver nanoparticles (NPs) using aqueous extract of Scrophularia Striata was demonstrated. In order to obtain the best formation conditions of NPs, different physicochemical parameters such as volume of the extract, silver ion concentration, temperature and reaction time were studied. Synthesized resultant NPs were characterized using UV, SEM, TEM, EDX, XRD, FT-IR and DLS analyses. A color change to brown after adding the extract to the silver nitrate solution was observed which indicated the formation of silver NPs. The synthesized silver NPs by Scrophularia Striata extract showed the highest absorbance at 426 nm. Plants have been used as stabilizing and reducing agents for NPs, due to their antioxidant properties and many secondary compounds.

Authors:Tayeb AB Matin, Nahid Ghasemi, Keivan Ghodrati, Majed Ramezani

Nowadays silver nanoparticles are produced by different chemical methods. Which have disadvantages such as instability of the solution and also require advanced equipment for production. So, green synthesis routes have attracted the attention of researchers for producing nanoparticles that have the minimum environmental hazards and require simple equipment for production. Herbal extracts can be used as a green route to synthesize silver nanoparticles. In this work, synthesis of silver nanoparticles was carried out using Thymbra spicata L. herbal extract (with the local name of zoofai). Silver nitrate was added to the extract and the effect of silver nitrate concentration, volume of the extract, temperature and time on silver nanoparticles synthesis was investigated. The synthesized nanoparticles have been characterized by UV-Vis spectroscopy, transmission electron microscopy (TEM), XRD, DLS, scanning electron microscopy (SEM), X-ray diffraction spectroscopy (EDX), and FT-IR. At UV-Visible spectrum, the presence of a peak at 430 nm indicates the biological synthesis of this nanoparticle in the presence of extract, and TEM image showed the spherical shape for the nanoparticle. Particle size distribution and average particle size were found to be about 40 nm by DLS. XRD image confirmed face-centered cubic nanocrystals with an average size of 21.3 nm, and SEM images were also well-matched with TEM and XRD images. Many organic dyes, such as methylene blue cationic dye, are toxic, carcinogenic and non-degradable because of their complex aromatic structure and high solubility in water. Therefore, it is necessary to remove them from wastewater. In this study, the efficiency of nanoparticles in the removal of methylene blue from water was also investigated by changing some parameters such as silver nanoparticle dosage, concentration of methylene blue and time, and it was found that the removal procedure is well done.

Authors:Tayeb AB Matin, Nahid Ghasemi, Keivan Ghodrati, Majed Ramezani

A novel polyionene modified magnetic nanoparticle with a core-shell-shell structure was developed for utilization as a heterogeneous catalyst in the metal free synthesis of dihydropyrimidinone derivatives under solvent-free conditions at 100 ◦C. The structural, surface, and magnetic characteristic of the nano sized catalyst were investigated by various techniques such as infrared spectroscopy (FT-IR), nucleus magnetic resonance (HNMR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX), thermo gravimetric analysis (TGA), differential scanning calorimeter (DSC), and vibrating sample magnetometer (VSM). The supported catalyst could simply separated and recovered from the reaction mixture with the assistance of an external magnet and reused at least 7 times without significant degradation in the activity.

Authors: Elham Dezfoolinezhad, Keivan Ghodrati, Rashid Badri

Tissue culture is a new approach for production of secondary metabolites with many advantages over conventional methods. Elicitors such as nano particles are molecules that can stimulate the production of secondary metabolites.

Authors: Kavianifar S (M.Sc.), Ghodrati K (Ph.D.), Naghdi Badi H (Ph.D.), Etminan A (Ph.D.)

A novel Fe3O4@SiO2@(CH2)3N+Me3I3- magnetite nanoparticle was prepared and utilized in the synthetic conversion of aldehydes to imidazole derivatives in solvent-free conditions. These functionalized magnetic core–shell nanoparticles (MNPs) were characterized by Standard technique such as TEM, SEM, EDX, FT-IR, XRD, and VSM. The work up of reaction was very simple containing only a magnetic decantation. This novel catalyst could be separated easily and recycled several times without any significant decreasing of catalytic activity.

Authors: Esmail Korani, Keivan Ghodrati, Manzarbano Asnaashari

A novel Fe3O4@SiO2@(CH2)3N+Me3I−3 magnetite nanoparticle was prepared and utilized in the synthetic conversion of aldehydes to imidazole derivatives in solventfree conditions. These functionalized magnetic core–shell nanoparticles (MNPs) were characterized by standard techniques such as TEM, SEM, EDX, FTIR, XRD, and VSM. The workup of the reaction was very simple containing only a magnetic decantation. This novel catalyst could be separated easily and recycled several times without any significant decrease of catalytic activity.

Authors: Esmail Korani, Keivan Ghodrati, Manzarbano Asnaashari

The four-component Hantzsch condensation reaction of dimedone, ethyl acetoacetate, ammonium acetate, and various aromatic and aliphatic aldehydes in the presence of catalytic amount of a magnetic nanoparticle-supported tribromide, as a green catalyst, under solvent‐free conditions at 80 °C affords functionalized 5-oxo-hexahydroquinolines in good to excellent yields. The magnetic Fe3O4-SiO2-(CH2)3N+Me3Br3–, was characterized by infrared spectroscopy (FT-IR), X-ray diffraction (XRD)spectroscopy, transmission electron microscope (TEM) and vibrating sample magnetometer (VSM). The method offers several advantages including high yields, short reaction time, simple work-up procedure and catalyst reusability for several runs. The catalyst could be readily separated by using a magnetic force and reused six times without any significant loss of catalytic activity.

Authors: Azita Farrokhi, Issa Yavari, Keivan Ghodrati

New Fe3O4@SiO2@polyionene/Br3 core–shell–shell magnetite nanoparticles were prepared using a co-precipitation method and were used in the syntheses of imidazole derivatives under solvent-free conditions. The polyionene was easily prepared by reacting DABCO and 1,4-dibromo butane in DMF/ methanol. It was then added to the previously formed layers and magnetic core–shell nanoparticles (P-MNPs) were functionalized. All the resultant nanoparticles were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and vibrating sample magnetometry (VSM). The catalyst was readily recovered by simple magnetic decantation and can be recycled several times with no significant loss of catalytic activity.

Authors: Elham Dezfoolinezhad, Keivan Ghodrati and Rashid Badri

A simple and effective synthesis of 3,4-dihydropyrimidin-2(1H)-one and thione derivatives has been developed in the presence of nano cobalt manganese oxide as catalyst under thermal solvent-free conditions. The proposed procedure ensures easy to handle, recyclable, and good yields after purification by recrystallization. In addition, the products were characterized by H NMR and C NMR.

Authors: Changiz Karami, Hadi Mohammadi, Keivan Ghodrati, Hossein Ahmadian, Fariba Jamshidi, Maryam Nouri , Nahid Haghnazarie