Electrosynthesis of gold nanoparticles mediated by methylviologen using a gold anode in single compartment cell

© 2017Methylviologen mediated reduction of AuI ions generated in situ by dissolution of a gold anode in single compartment cell has been used for the electrosynthesis of spherical gold nanoparticles (Au-NPs) stabilized by poly(N-vinylpyrrolidone). The size of Au-NPs was from 15±6 to 27±9 nm, depending on the electrosynthesis conditions. Au-NPs were characterized by cyclic voltammetry, UV-VIS spectroscopy, dynamic light scattering, scanning and transmission electron microscopy

Fullerene mediated electrosynthesis of Au/C<inf>60</inf>nanocomposite

© 2017 The Electrochemical Society. All rights reserved. C 60 fullerene mediated electroreduction of Au(I) at potentials of the C 60 /C 60 •− redox couple was used to perform the electrosynthesis of an AuNP/C 60 nanocomposite in DCB-DMF (2:1)/0.1 M Bu 4 NCl medium. The nanocomposite consists of separate gold nanoparticles with various shapes and a mean size of ~27 ± 14 nm, as well as larger nanoaggregates of such particles, isolated in a fullerene matrix. The mean size of metal crystallites is 9–14 nm. The electrolysis occurs efficiently, and Au(I) is quantitatively reduced to Au(0) upon consumption of the theoretical amount of electricity. The resulting metal nanoparticles and the nanocomposite are not deposited on the electrode and are completely stabilized in the solution bulk. All the particles were characterized by electron microscopy methods (SEM, HR TEM) and X-ray powder diffraction (XRPD)

Molecular oxygen as a mediator in the electrosynthesis of gold nanoparticles in DMF

© 2016 Elsevier B.V.The possibility of using of molecular oxygen as a mediator in electrosynthesis of metal nanoparticles by reduction of their ions and complexes in aprotic media was demonstrated by the example of electrosynthesis of gold nanoparticles by reduction of Au(I) in DMF

Methylviologen mediated electrochemical reduction of AgCl - A new route to produce a silica core/Ag shell nanocomposite material in solution

© 2015 Elsevier B.V. All rights reserved. Methylviologen mediated electrochemical reduction of AgCl precipitate to Ag0 in the presence of alkylamino-modified silica nanoparticles (SiO2-NHR) in an aqueous medium was performed. The main products of reduction at potentials of the MV2 +/MV•+ redox couple are spherical SiO2-NHR/Ag core/shell nanoparticles (size range 120-160 nm) in solution

Methylviologen-mediated electrochemical synthesis of platinum nanoparticles in solution bulk

© 2017, Pleiades Publishing, Ltd.Platinum nanoparticles (PtNPs) are synthesized by methylviologen-mediated reduction of PtCl2 at the potentials of the MV2+/MV•+ redox couple in 40% aqueous DMF solution. In the absence of stabilizing agents and in the presence of a stabilizer in the form of spherical silica NPs or alkylamine-modified silica NPs (SiO2-NHR), a part of PtNPs (14–18%) are deposited on the electrode while the rest of particles remain in solution to form coarse aggregates which precipitate. In the latter case, PtNPs are also partly bound to form individual ultrafine NPs (3 ± 2 nm) on the SiO2-NHR surface. In the presence of polyvinylpyrrolidone (PVP), the generated PtNPs (18 ± 9 nm) neither aggregate nor deposit on the cathode but are completely stabilized in solution being encapsulated within the PVP matrix. The obtained PtNPs are characterized by the methods of dynamic light-scattering and electron microscopy

Methylviologen mediated electrosynthesis of gold nanoparticles in the solution bulk

© 2015 The Royal Society of Chemistry. Electrosynthesis of gold nanoparticles (AuNp) was carried out by methylviologen mediated reduction of Au(i) at potentials of the MV2+/MV+ redox couple in water/0.1 M NaCl medium, in the absence and in the presence of stabilizers. In all the cases, AuNp are formed in the solution bulk and are not deposited on the cathode. In the absence of stabilizers, AuNp (14-100 nm) coalesce to give aggregates of various shapes that eventually form a deposit. Sonication reversibly destructs the deposit into nanoparticles. In the presence of alkylamino-modified silicate nanoparticles (SiO2-NHR, 120-160 nm), spherical AuNp (≤20 nm) are bound as inclusions in the SiO2-NHR surface layer. Polyvinylpyrrolidone (40 000 D) stabilizes spherical AuNp with a mean diameter of 5-14 nm. All the particles were characterized by electron microscopy methods (SEM, STEM) and X-ray powder diffraction (XRPD)

Photophysical and electrochemical properties of the outer-sphere associate of [Ru(bipy)3]2+ with p-sulfonatothiacalix[4]arene

1H NMR titration and X-ray diffraction analysis revealed that [Ru(bipy)3]2+ forms an outer-sphere inclusion complex with p-sulfonatothiacalix[4]arene in a ratio of 1: 1 in both aqueous solutions and the solid state. According to cyclic voltammograms and fluorimetric data, the outer-sphere association of [Ru(bipy)3]2+ with p-sulfonatothiacalix[4]arene changes the reversible character of the electrochemical oxidation of [Ru(bipy)3]2+ and lowers its emission intensity. © 2008 Springer Science+Business Media, Inc

Electrochemically driven molecular rotors based on ferrocene-1,1'-diyl-bisphosphinic acids

© 2015, Pleiades Publishing, Ltd. Based on ferrocene-1,1'-diyl-bisphosphinic acids Fc[P(R)(O)OH]2 (R = H, Me, Et, Ph) in methanol, two types of electrochemically driven molecular rotors are developed. Monoanions of acids are fixed in the cis-conformation due to the presence of an intramolecular hydrogen bond, whereas dianions are fixed in the trans-conformation due to electrostatic repulsion forces. Upon the transformation of monoanions to dianions, the controlled rotation of cyclopentadienyl rings from cis to trans-conformation occurs; the reverse switching leads to the reverse rotation. In one type of rotors, the rotation is controlled by the reversible variation of the solution pH and composition in the electrochemical oxidation-re-reduction cycle of N-phe-nyl-N'-isopropyl-1,4-phenylenediamine; in the other type, the rotation is determined by the one electron oxidation-re-reduction of the ferrocene nucleus in monoanions. The latter rotor type at room temperature can operate stably only for a short time (τ< 1 s) and at longer times is irreversibly destructed during the oxidation stage

Fullerene-mediated electrosynthesis of Ag–C<inf>60</inf>nanocomposite in a water-organic two-phase system

© 2017 By example of fullerene-mediated electrosynthesis of Ag–C 60 nanocomposite in water–o-dichlorobenzene, the possibility of using a liquid–liquid two-phase system for the electro- synthesis of metal nanoparticles has been demonstrated for the first time

Highly active Pd-Ni nanocatalysts supported on multicharged polymer matrix

© The Royal Society of Chemistry 2017. In this article, we report the synthesis of mono- and bimetallic Pd-Ni nanocomposites supported on a multicharged polymeric matrix for catalytic applications. The morphology and catalytic properties of the composites depend on the Pd-Ni ratio. In the Suzuki-Miyaura coupling reaction, the composite with an equal amount of palladium and nickel is the most active and the reaction occurs within six hours in water at room temperature