Effect of metal ions with reducing properties on hydrogels containing catechol groups

The new compounds M(SC6F5), where M = Cs, Tl, Cu, Au, and Ph3Pb; M(SC6F5)2, where M = Pb, Cd, Hg, Ni, and Pt; M(SC6F5)3, where M = As or Bi; and Sn(SC6F5)4 have been prepared from pentafluorothiophenol and metal ions in aqueous solution. Zn(SC6F5)2 has been prepared from zinc oxide and pentafluorothiophenol in methanol. The compounds have been characterized, and their infrared spectra and 1H and 19F nuclear magnetic resonance spectra examined.Some of the reducing properties of pentafluorothiophenol and its polymerization have been studied.

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A Review of Reducing Agents in Chemical and Natural Synthesis of Metallic Nanoparticles

Nanoscience &Nanotechnology-Asia ◽

10.2174/2210681210999200831100212 ◽

2020 ◽

Vol 10 ◽

Author(s):

PB Vandana ◽

Mangesh Pradeep Kulkarni ◽

Sagar Tanwar ◽

Poluri Sesha Sai Kiran ◽

Gurmandeep Kaur ◽

...

Keyword(s):

Metal Ions ◽

Metallic Nanoparticles ◽

Cost Effective ◽

Natural Antioxidants ◽

Reducing Agents ◽

Synthesis Methods ◽

Methods Of Synthesis ◽

Synthetic Agents ◽

Special Mention ◽

Reducing Properties

: Metal nanoparticular synthesis techniques essentially involve a reduction of metal ions to convert them into nanoparticles. Reducing agents originate from natural and synthetic sources. Chemical methods involve application of synthetic agents that are not healthy and eco-friendly and thus, there is a need for green methods. Green synthesis methods involve reduction of metal ions using plant-based extracts or phytoconstituents and microorganisms like bacteria, yeast, and fungi. These methods have been found to be cost-effective, more efficient and eliminate the application of hazardous chemicals. The phytoconstituents involved in the synthesis of metal nanoparticles are rich in polyols and antioxidants, which in addition to reducing properties, also offer stabilization of formed nanoparticles. Moreover, the size of nanoparticles can also be controlled based on the mechanism of reducing agent involved therein. The present review is an attempt to highlight the methods of synthesis of metallic nanoparticles with a special mention of applications of various natural antioxidants in their synthesis.

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HREM Study of electron-induced surface radiation damage in ReO3

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100087495 ◽

1991 ◽

Vol 49 ◽

pp. 636-637

Author(s):

R. Ai ◽

H.-J. Fan ◽

L. D. Marks

Keyword(s):

Transition Metal ◽

Metal Ions ◽

Metal Oxides ◽

Electron Irradiation ◽

Transition Metal Oxides ◽

Carbon Film ◽

Transition Metal Ions ◽

Surface Radiation ◽

Valence Transition ◽

Electron Microscopes

It has been known for a long time that electron irradiation induces damage in maximal valence transition metal oxides such as TiO2, V2O5, and WO3, of which transition metal ions have an empty d-shell. This type of damage is excited by electronic transition and can be explained by the Knoteck-Feibelman mechanism (K-F mechanism). Although the K-F mechanism predicts that no damage should occur in transition metal oxides of which the transition metal ions have a partially filled d-shell, namely submaximal valence transition metal oxides, our recent study on ReO3 shows that submaximal valence transition metal oxides undergo damage during electron irradiation.ReO3 has a nearly cubic structure and contains a single unit in its cell: a = 3.73 Å, and α = 89°34'. TEM specimens were prepared by depositing dry powders onto a holey carbon film supported on a copper grid. Specimens were examined in Hitachi H-9000 and UHV H-9000 electron microscopes both operated at 300 keV accelerating voltage. The electron beam flux was maintained at about 10 A/cm2 during the observation.

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ELNES of Iron Compounds

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100133734 ◽

1990 ◽

Vol 48 (2) ◽

pp. 28-29

Author(s):

Hiroki Kurata ◽

Kazuhiro Nagai ◽

Seiji Isoda ◽

Takashi Kobayashi

Keyword(s):

Energy Loss ◽

Metal Ions ◽

Energy Resolution ◽

Transition Metal Oxides ◽

Local Symmetry ◽

Iron Compounds ◽

Fine Structures ◽

Electron Energy Loss ◽

Fe Ions ◽

Electron Energy Loss Spectra

Electron energy loss spectra of transition metal oxides, which show various fine structures in inner shell edges, have been extensively studied. These structures and their positions are related to the oxidation state of metal ions. In this sence an influence of anions coordinated with the metal ions is very interesting. In the present work, we have investigated the energy loss near-edge structures (ELNES) of some iron compounds, i.e. oxides, chlorides, fluorides and potassium cyanides. In these compounds, Fe ions (Fe2+ or Fe3+) are octahedrally surrounded by six ligand anions and this means that the local symmetry around each iron is almost isotropic.EELS spectra were obtained using a JEM-2000FX with a Gatan Model-666 PEELS. The energy resolution was about leV which was mainly due to the energy spread of LaB6 -filament. The threshole energies of each edges were measured using a voltage scan module which was calibrated by setting the Ni L3 peak in NiO to an energy value of 853 eV.

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