Synthesis of star-shaped CuO nanoparticles supported on magnetic functionalized graphene: Catalytic and antibacterial activity

In this study, graphene oxide was modified during consecutive functionalization steps with 1,4-diphenylamine, cyanuric chloride, and ethylenediamine. Then, star-shaped CuO nanoparticles were synthesized on modified graphene oxide using the seed-mediated growth method in which nucleation, growth stages, and reduction of graphene oxide to graphene occurred simultaneously. After ensuring successful synthesis of CuO nanoparticles and to facilitate recycling, a magnetization process was utilized by adding iron oxide nanoparticles. This nanocomposite was characterized by transmission electron microscopy, X-ray powder diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. The prepared heterogeneous catalyst was investigated for the reduction of organic dyes in the presence of NaBH₄ as a reducing reagent. The kinetic data obtained for the reduction of methyl orange (MO), methylene blue (MB), 4-nitrophenol (4-NP), and rhodamine 6G (Rh6G) were fitted to first-order rate equations, and the calculated rate constants for the reduction of MO, MB, 4-NP and Rh6G were as follows: −0.091, −0.071, −0.045, and 0.040, respectively. As star-shaped CuO nanoparticles showed a higher antibacterial effect compared to spherical-shaped CuO nanoparticles, the antibacterial activity of star-shaped CuO nanoparticles immobilized on magnetic functionalized graphene was evaluated against Gram-positive and Gram-negative bacteria through an agar well diffusion assay and demonstrated more antibacterial activity against gram-positive bacteria.     

Sensitive Biosensor Based on Urease/In2O5Sn Nano-Coated Fluorinated SnO2 for Urea Detection in Blood Serum

Journal of Analytical Chemistry - A sensitive electrochemical matrix based on In2O5Sn nanoparticles modified fluorinated tin oxide (SnO2:F) conducting glass was reported. Besides, urease (Urs) was...     

In situ green synthesis of Cu‐Ni bimetallic nanoparticles supported on reduced graphene oxide as an effective and recyclable catalyst for the synthesis of N‐benzyl‐N‐aryl‐5‐amino‐1H‐tetrazoles

In the present work, for the first time we have designed a novel approach for the synthesis of N‐benzyl‐N‐aryl‐5‐amino‐1H‐tetrazoles using reduced graphene oxide (rGO) decorated with Cu‐Ni bimetallic nanoparticles (NPs). In situ synthesis of Cu/Ni/rGO nanocomposite was performed by a cost efficient, surfactant‐free and environmentally benign method using Crataegus azarolus var. aronia L. leaf extract as a stabilizing and reducing agent. Phytochemicals present in the extract can be used to reduce Cu²⁺ and Ni²⁺ ions and GO to Cu NPs, Ni NPs and rGO, respectively. Analyses by means of FT‐IR, UV–Vis, EDS, TEM, FESEM, XRD and elemental mapping confirmed the Cu/Ni/rGO formation and also FT‐IR, NMR, and mass spectroscopy as well as elemental analysis were used to characterize the tetrazoles. The Cu/Ni/rGO nanocomposite showed the superior catalytic activity for the synthesis of N‐benzyl‐N‐aryl‐5‐amino‐1H‐tetrazoles within a short reaction time and high yields. Furthermore, this protocol eliminates the need to handle HN₃.     

Synthesis and characterization of Ni(II) complex functionalized silica-based magnetic nanocatalyst and its application in C–N and C–C cross-coupling reactions

Molecular Diversity - A new magnetically recoverable silica-based nickel(II) nanocatalyst was synthesized by a simple cost-effective procedure, which was characterized by TEM, SEM, XRD, VSM...     

Multilayer‐Functionalized Reduced Graphene Oxide Decorated with Gold Nanoparticles as a Designed Nanonanocatalyst for the Selective Oxidation of Cyclohexene by Molecular Oxygen in a Solvent‐Free System

The aerobic oxidation of cyclohexene is of great significance from the viewpoints of both fundamental and industry studies as it can transfer the petrochemical feedstock into valuable chemicals. In this research, gold nanoparticles were synthesized on the multi‐layer functionalized reduced graphene oxide . The surface of reduced graphene oxide (rGO) was modified with hydrophobic and hydrophilic layers to create the rGO with scattered hydrophilic positions. The gold nanoparticles were synthesized and immobilized simultaneously in small hydrophilic micro reactors in a mild condition. Characterization of synthesized nanocatalyst was confirmed with different techniques such as TEM, XRD, FT‐IR, and SEM. TEM images of synthesized catalyst show the gold nanoparticles have diameters less than 5 nm. Designed nanonanocatalyst was investigated for the selective liquid phase oxidation of cyclohexene with molecular oxygen in solvent free condition which after optimized conditions a maximum of 88% conversion and 91% selectivity was obtained.     

Application of stabilized zero valent iron nanoparticles for immobilization of lead in three contrasting spiked soils

Research on Chemical Intermediates - This study was conducted to synthesize and characterize the ZVINs stabilized with acid ascorbic (AAS-ZVINs) and to assess their ability to immobilize Pb2+ in...     

Fabrication of ultra‐small ruthenium nanoparticles on porous modified reduced graphene oxide and its application in solvent‐free oxidation of cyclohexene with molecular oxygen

In the present work, ruthenium nanoparticles were synthesized on functionalized reduced graphene oxide (rGO). First, the surface of rGO was modified with two para‐arsanilic acid and dithiooxamide promoters to create the rGO with scattered hydrophilic positions. The ruthenium nanoparticles were synthesized and immobilized simultaneously in small hydrophilic micro‐reactors under mild conditions. Characterization of the synthesized nanocatalyst was confirmed with different techniques, such as transmission electron microscopy (TEM), X‐ray diffraction, Fourier transform‐infrared and scanning electron microscopy. TEM images of the synthesized catalyst show the Ru nanoparticles have diameters less than 6 nm. The designed nanocatalyst was investigated for the selective liquid phase oxidation of cyclohexene with molecular oxygen in an autoclave under solvent‐free conditions, which obtained a maximum of 91% conversion and 90% selectivity under optimized conditions. The catalytic activity over rGO‐AO‐TO/Ru recycled catalyst remained at a satisfactory state after at least five runs.     

A simple and convenient synthesis of [1,2,4]triazolo/benzimidazolo ‎quinazolinone and [1,2,4]triazolo[1,5-<Emphasis Type="Italic">a</Emphasis>]pyrimidine derivatives catalyzed by ‎DABCO-based ionic liquids

DABCO-based ionic liquids were utilized for the preparation of [1,2,4]triazolo/benzimidazolo quinazolinone and [1,2,4]triazolo[1,5-a]pyrimidine derivatives in the adequate procedures. These methods involve three-component reaction between aldehydes, β-diketones and 3-amino-1,2,4-triazole or 2-aminobenzimidazole in the presence of 1,4-disulfo-1,4-diazabicyclo[2.2.2]octane-1,4-diium chloride ([DABCO](SO₃H)₂(Cl)₂) and 1,4-disulfo-1,4-diazabicyclo[2.2.2]octane-1,4-diium dihydrogen sulfate ([DABCO](SO₃H)₂(HSO₄)₂) as reusable and economical catalysts at 100 °C. These methods also show eco-friendly characters by elimination of solvent. Any by-product was not prepared through this method, and products were separated by a simple workup procedure. The other noticeable benefits of these procedures are excellent yields, short reaction times, mild reaction conditions and use of available and inexpensive materials.     

A theoretical study on the chirality detection of serine amino acid based on carbon nanotubes with and without Stone-Wales defects

In the present study, the interaction of serine (SER) amino acid (AA) with the pristine and defected carbon nanotubes (CNTs) has been investigated by employing the molecular dynamics (MD) and the density functional theory (DFT) approaches. Furthermore, the potential application of CNTs with and without the Stone-Wales (SW) defects in sensing of SER chirality has been studied. Our results confirm that introducing the chiral l and d SERs (LSER and DSER) exerts a significant effect on the electronic and optical properties of the CNTs with and without the SW defect. According to the MD results, it is observed that for all the structures, the obtained minimum distance is among the SER aliphatic segments and the tube atoms. The calculated structural and electronic properties of pristine and defected CNT are in good agreement with the reported research studies. The results indicate that pyramidalization angles (θ_p) at C atoms are altered in the presence of the SW defects. The overall increment of θ_p suggests that the reactivity has increased at the defective regions. In the case of CNT with one SW defect (CNTSW1), the central C–C bond of the SW defect is the most chemically reactive site. Our results establish that pristine CNT is a semiconductor when the LSER and DSER are adsorbed (with the band gap of 0.30 eV and 0.32 eV, respectively). The LSER-adsorbing CNT with two SW defects (CNTSW2) is a semiconductor with a reduced band gap (0.41 eV), while the DSER-adsorbing CNTSW2 is an n-type semiconductor (with a band gap of 0.70 eV). The optical properties are inferred from the dielectric functions of the CNTs. The most remarkable result belongs to the CNTSW2; the imaginary part of the CNTSW2 dielectric function can sensitively distinguish the chirality of the SER amino acid.