scholarly journals Mechanism of Producing Metallic Nanoparticles, with an Emphasis on Silver and Gold Nanoparticles, Using Bottom-Up Methods

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2968
Author(s):  
Basil Raju Karimadom ◽  
Haya Kornweitz
Keyword(s):  
Aqueous Solution ◽  
Carbon Monoxide ◽  
Gold Nanoparticles ◽  
Solid State ◽  
Metallic Nanoparticles ◽  
Reduction Potential ◽  
Metallic Ions ◽  
Bottom Up ◽  
Moderate Reduction ◽  
Metallic Cations

Bottom-up nanoparticle (NP) formation is assumed to begin with the reduction of the precursor metallic ions to form zero-valent atoms. Studies in which this assumption was made are reviewed. The standard reduction potential for the formation of aqueous metallic atoms—E0(Mn+aq/M0aq)—is significantly lower than the usual standard reduction potential for reducing metallic ions Mn+ in aqueous solution to a metal in solid state. E0(Mn+aq/M0solid). E0(Mn+aq/M0aq) values are negative for many typical metals, including Ag and Au, for which E0(Mn+aq/M0solid) is positive. Therefore, many common moderate reduction agents that do not have significantly high negative reduction standard potentials (e.g., hydrogen, carbon monoxide, citrate, hydroxylamine, formaldehyde, ascorbate, squartic acid, and BH4−), and cannot reduce the metallic cations to zero-valent atoms, indicating that the mechanism of NP production should be reconsidered. Both AgNP and AuNP formations were found to be multi-step processes that begin with the formation of clusters constructed from a skeleton of M+-M+ (M = Ag or Au) bonds that is followed by the reduction of a cation M+ in the cluster to M0, to form Mn0 via the formation of NPs. The plausibility of M+-M+ formation is reviewed. Studies that suggest a revised mechanism for the formation of AgNPs and AuNPs are also reviewed.

Separation of phenylenediamine isomers by using decamethylcucurbit[5]uril

2021 ◽  
Author(s):  
Long Cao ◽  
Han-Ling Guo ◽  
Rui Lian Lin ◽  
Li-Fei Tian ◽  
Zhi-Hua Zhang ◽  
...  
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Solid State ◽  
Phenylenediamine Isomers

Using multiple techniques, this work studied the binding behaviors of decamethylcucurbit[5]uril (Me10Q[5]) with o-, m- and p-phenylenediamine (PDA) isomers both in solid state and in aqueous solution. Experimental data indicate...

Bis(1-phenyl-1-propyne) complexes of tungsten(II): crystal structures of [WI2(CO)(NCR)(η2-MeC2Ph)2] (R = Me, Et, or Ph)

2001 ◽  
Vol 79 (3) ◽  
pp. 263-271
Author(s):  
Paul K Baker ◽  
Michael GB Drew ◽  
Deborah S Evans
Keyword(s):  
Carbon Monoxide ◽  
Solid State ◽  
Crystal Structures ◽  
Octahedral Geometry ◽  
X Ray ◽  
X Ray Crystallography ◽  
Alkyne Complexes ◽  
First Time

Reaction of [WI2(CO)3(NCMe)2] with two equivalents of 1-phenyl-1-propyne (MeC2Ph) in CH2Cl2, and in the absence of light, gave the bis(1-phenyl-1-propyne) complex [WI2(CO)(NCMe)(η2-MeC2Ph)2] (1) in 77% yield. Treatment of equimolar quantities of 1 and NCR (R = Et, i-Pr, t-Bu, Ph) in CH2Cl2 afforded the nitrile-exchanged products, [WI2(CO)(NCR)(η2-MeC2Ph)2] (2-5) (R = Et (2), i-Pr (3), t-Bu (4), Ph (5)). Complexes 1, 2, and 5 were structurally characterized by X-ray crystallography. All three structures have the same pseudo-octahedral geometry, with the equatorial sites being occupied by cis and parallel alkyne groups, which are trans to the cis-iodo groups. The trans carbon monoxide and acetonitrile ligands occupy the axial sites. In structures 1 and 2, the methyl and phenyl substituents of the 1-phenyl-1-propyne ligands are cis to each other, whereas for the bulkier NCPh complex (5), the methyl and phenyl groups are trans to one another. This is the first time that this arrangement has been observed in the solid state in bis(alkyne) complexes of this type.Key words: bis(1-phenyl-1-propyne), carbonyl, nitrile, diiodo, tungsten(II), crystal structures.

scholarly journals Electrochemiluminescence Study of Europium (III) Complex with Coumarin3-Carboxylic Acid

2008 ◽  
Vol 2008 ◽  
pp. 1-6 ◽  
Author(s):  
Stefan Lis ◽  
Krzysztof Staninski ◽  
Tomasz Grzyb
Keyword(s):  
Aqueous Solution ◽  
Spectral Analysis ◽  
Energy Transfer ◽  
Solid State ◽  
Carboxylic Acid ◽  
Elemental Analysis ◽  
Aluminium Electrode ◽  
The Eu

The europium (III) complex of coumarin-3-carboxylic acid (C3CA) has been prepared and characterized on the basis of elemental analysis, IR, and emission (photoluminescence and electrochemiluminescence) spectroscopy. The synthesised complex having a formula Eu was photophysically characterized in solution and in the solid state. Electrochemiluminescence, ECL, of the system containing the Eu(III)/C3CA complex was studied using an oxide-covered aluminium electrode. The goal of these studies was to show the possibility of the use of electrochemical excitation of the Eu(III) ion in aqueous solution for emission generation. The generated ECL emission was very weak, and therefore its measurements and spectral analysis were carried out with the use of cut-off filters method. The studies proved a predominate role of the ligand-to-metal energy transfer (LMET) in the generated ECL.

EXCITON–PLASMON INTERACTION IN MONOLAYERS OF METAL-SEMICONDUCTOR NANOSTRUCTURES

2011 ◽  
Vol 10 (04n05) ◽  
pp. 623-627 ◽  
Author(s):  
M. HARIDAS ◽  
L. N. TRIPATHI ◽  
J. K. BASU
Keyword(s):  
Gold Nanoparticles ◽  
Metallic Nanoparticles ◽  
Near Field ◽  
Blue Shift ◽  
Optical Microscope ◽  
Peak Position ◽  
Photoluminescence Spectra ◽  
Langmuir Blodgett ◽  
Near Field Scanning ◽  
Cdse Nanorods

Effect of shape and density on the energy transfer between metallic nanoparticles and semi conducting nanostructures was studied by observing the photoluminescence spectra using near field scanning optical microscope. The monolayers of gold nanoparticles, CdSe nanorods and composite with different number ratios were prepared using Langmuir Blodgett method. The spectra collected from the films with different number ratios of CdSe and gold shows a systematic variation of peak position and intensity as a function of number density of CdSe . The photoluminescence spectra collected from composite monolayer is blue shifted compared to the spectra from CdSe nanorods monolayer. Further we observed a blue shift in peak position and reduction emission intensity with respect to increase in the fraction of gold nanoparticles and surface density. We have provided explanation for the observed behavior in terms of strong exciton–plasmon interactions in the compact hybrid monolayers.

Enhanced adsorption removal of methyl orange from aqueous solution by nanostructured proton-containing δ-MnO2

2015 ◽  
Vol 3 (10) ◽  
pp. 5674-5682 ◽  
Author(s):  
Yan Liu ◽  
Chao Luo ◽  
Jian Sun ◽  
Haizhen Li ◽  
Zebin Sun ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Methyl Orange ◽  
Solid State ◽  
Solid State Reaction ◽  
Proton Exchange ◽  
Precipitation Method ◽  
Homogeneous Precipitation ◽  
Adsorption Removal ◽  
Homogeneous Precipitation Method ◽  
Enhanced Adsorption

Two nanostructured proton-containing δ-MnO2 (H-δ-MnO2) materials were synthesized through proton exchange for K-containing δ-MnO2 (K-δ-MnO2) nanosheets and nanoparticles prepared by the hydrothermal homogeneous precipitation method and solid-state reaction.

scholarly journals Biosynthesis and Potential Applications of Silver and Gold Nanoparticles and Their Chitosan-Based Nanocomposites in Nanomedicine

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Haliza Katas ◽  
Noor Zianah Moden ◽  
Chei Sin Lim ◽  
Terence Celesistinus ◽  
Jie Yee Chan ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Metallic Nanoparticles ◽  
Cost Effective ◽  
One Pot ◽  
Silver And Gold Nanoparticles ◽  
Stabilizing Agents ◽  
Cost Effective Method ◽  
Multistep Process ◽  
Potential Applications ◽  
Biological Sources

Biosynthesized or biogenic metallic nanoparticles, particularly silver and gold nanoparticles (AgNPs and AuNPs, respectively), have been increasingly used because of their advantages, including high stability and loading capacity; moreover, these nanoparticles are synthesized using a green and cost-effective method. Previous studies have investigated reducing and/or stabilizing agents from various biological sources, including plants, microorganisms, and marine-derived products, using either a one-pot or a multistep process at different conditions. In addition, extensive studies have been performed to determine the biological or pharmacological effects of these nanoparticles, such as antimicrobial, antitumor, anti-inflammatory, and antioxidant effects. In the recent years, chitosan, a natural cationic polysaccharide, has been increasingly investigated as a reducing and/or stabilizing agent in the synthesis of biogenic metallic nanoparticles with potential applications in nanomedicine. Here, we have reviewed the mechanism of biosynthesis and potential applications of AgNPs and AuNPs and their chitosan-mediated nanocomposites in nanomedicine.

Mechanistic studies on the decomposition of sodium cyanide in aqueous solution and in the solid state

2005 ◽  
Vol 153 (2-3) ◽  
pp. 125-131 ◽  
Author(s):  
Hiroshi Nishioka ◽  
Mayumi Nishikawa ◽  
Munehiro Katagi ◽  
Hitoshi Tsuchihashi ◽  
Osamu Muraoka
Keyword(s):  
Aqueous Solution ◽  
Solid State ◽  
Sodium Cyanide ◽  
Mechanistic Studies

A fluorescence study on the complexation of Sm(iii), Eu(iii) and Tb(iii) with tetraalkyldiglycolamides (TRDGA) in aqueous solution, in solid state, and in solvent extraction

2016 ◽  
Vol 45 (46) ◽  
pp. 18484-18493 ◽  
Author(s):  
Fei Kou ◽  
Suliang Yang ◽  
Hongjuan Qian ◽  
Lihua Zhang ◽  
Christine M. Beavers ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Solid State ◽  
Solvent Extraction ◽  
Lanthanide Ions ◽  
Tridentate Ligand ◽  
Fluorescence Study ◽  
Trivalent Lanthanide

Trivalent lanthanide ions form 1 : 1, 1 : 2, and 1 : 3 complexes with tridentate ligand TMDGA in 1 M H/NaNO3 and form 1 : 3 extracted complexes with DMDODGA during solvent extraction.

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