Stabilisation of tri-valent ions with a vacant coordination site at a corrole–metal interface

2020 ◽  
Vol 56 (76) ◽  
pp. 11219-11222
Author(s):  
P. S. Deimel ◽  
P. Casado Aguilar ◽  
M. Paszkiewicz ◽  
D. A. Duncan ◽  
J. V. Barth ◽  
...  
Keyword(s):  
Oxidation State ◽  
Metal Interface ◽  
Coordination Site

We show that a tri-valent oxidation state is retained in in situ metallated V and Ti corroles in contact with a Ag(111) surface.

scholarly journals Selenium– and tellurium–halogen reagents

2018 ◽  
Vol 3 (12) ◽  
Author(s):  
Tristram Chivers ◽  
Risto S. Laitinen
Keyword(s):  
Oxidation State ◽  
Halogen Bond ◽  
The Other ◽  
Oxidation States ◽  
Alkyl Aryl ◽  
Organic Selenium ◽  
Formal Oxidation State ◽  
Wide Range ◽  
Inorganic And Organic

Abstract Selenium and tellurium form binary halides in which the chalcogen can be in formal oxidation states (IV), (II) or (I). They are versatile reagents for the preparation of a wide range of inorganic and organic selenium and tellurium compounds taking advantage of the reactivity of the chalcogen–halogen bond. With the exception of the tetrafluorides, the tetrahalides are either commercially available or readily prepared. On the other hand, the low-valent species, EX2 (E = Se, Te; X = Cl, Br) and E2X2 (E = Se, Te; X = Cl, Br) are unstable with respect to disproportionation and must be used as in situ reagents. Organoselenium and tellurium halides are well-known in oxidation states (IV) and (II), as exemplified by REX3, R2EX2 and REX (R = alkyl, aryl; E = Se, Te; X = F, Cl, Br, I); mixed-valent (IV/II) compounds of the type RTeX2TeR are also known. This chapter surveys the availability and/or preparative methods for these widely used reagents followed by examples of their applications in synthetic inorganic and organic selenium and tellurium chemistry. For both the binary halides and their organic derivatives, the discussion is subdivided according to the formal oxidation state of the chalcogen.

The Combined Effect of Chemical and Structural Factors on Pitting Corrosion Induced by MnS-(Cr, Mn, Al)O Duplex Inclusions

CORROSION ◽  
10.5006/2581 ◽  
2017 ◽  
Vol 74 (3) ◽  
pp. 312-325 ◽  
Author(s):  
Cheng Man ◽  
Chaofang Dong ◽  
Kui Xiao ◽  
Qiang Yu ◽  
Xiaogang Li
Keyword(s):  
Pitting Corrosion ◽  
Selective Dissolution ◽  
Dissolution Mechanism ◽  
Structural Factors ◽  
Metal Interface ◽  
Kelvin Probe ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Individual

In situ atomic force microscopy, scanning Kelvin probe force microscopy, and potential pulse technology were used to study the pitting behavior induced by inclusions in AM355 martensitic stainless steel. The MnS-(Cr, Mn, Al)O duplex inclusion exhibited the highest sensitivity to the pitting corrosion with respect to the individual MnS and (Cr, Mn, Al)O inclusions. When exposed to a solution containing Cl−, the selective dissolution occurred on the sulfide segment of the duplex inclusion, leading to trenching along the oxide part. The dissolution mechanism of MnS segment in the duplex inclusion is similar to the individual MnS inclusion. The Cr depletion in the boundary layer at the inclusion/metal interface promoted the transition from metastable to stable pitting corrosion in the duplex inclusion.

Insights into sulfur poisoning and regeneration of Cu-SSZ-13 catalysts: In situ Cu and S K-edge XAS studies

2021 ◽  
Author(s):  
Vitaly Mesilov ◽  
Sandra Dahlin ◽  
Susanna Liljegren Bergman ◽  
Peter Sams Hammershøi ◽  
Shibo Xi ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Oxidation State ◽  
Absorption Spectroscopy ◽  
Catalytic Reduction ◽  
Sulfur Poisoning ◽  
X Ray ◽  
Scr Catalysts ◽  
X Ray Absorption

In situ Cu and S K-edge X-ray absorption spectroscopy (XAS) was used for the investigation of sulfur-poisoned and regenerated Cu-SSZ-13 selective catalytic reduction (SCR) catalysts. Sulfur in the oxidation state...

Performance of enhanced DuBois type water reduction catalysts (WRC) in artificial photosynthesis – effects of various proton relays during catalysis

2019 ◽  
Vol 215 ◽  
pp. 141-161 ◽  
Author(s):  
Wolfgang Viertl ◽  
Johann Pann ◽  
Richard Pehn ◽  
Helena Roithmeyer ◽  
Marvin Bendig ◽  
...  
Keyword(s):  
Oxidation State ◽  
Artificial Photosynthesis ◽  
Metal Oxidation ◽  
Water Reduction ◽  
Coordination Site ◽  
Proton Relay ◽  
Additional Coordination ◽  
Type Water ◽  
Reduction Catalysts

A pincer type ligand provides an additional coordination site or a proton relay depending on the metal oxidation state.

scholarly journals In situ XAS study of the local structure and oxidation state evolution of palladium in a reduced graphene oxide supported Pd(ii) carbene complex during an undirected C–H acetoxylation reaction

2019 ◽  
Vol 9 (8) ◽  
pp. 2025-2031 ◽  
Author(s):  
Ning Yuan ◽  
Maitham H. Majeed ◽  
Éva G. Bajnóczi ◽  
Axel R. Persson ◽  
L. Reine Wallenberg ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Oxidation State ◽  
Local Structure ◽  
Carbene Complex ◽  
In Situ Xas ◽  
Reduced Graphene ◽  
State Evolution ◽  
Supported Pd

In situ XAS is used to reveal the evolution of palladium species during an undirected C–H acetoxylation reaction.

In Situ X-Ray Diffraction and In Situ X-Ray Absorption Spectroscopy for Investigation of Intercalation Batteries: Application to the Alkaline H+/γ-MnO2 system.

1990 ◽  
Vol 210 ◽  
Author(s):  
C. Lévy-Clèment ◽  
C. Mondoloni ◽  
C. Godart ◽  
R. Cortès
Keyword(s):  
Charge Transfer ◽  
Oxidation State ◽  
Absorption Spectroscopy ◽  
Crystallographic Structure ◽  
X Ray Diffraction ◽  
Alkaline Batteries ◽  
X Ray ◽  
In Situ Techniques ◽  
X Ray Absorption

AbstractThis paper presents applications of in situ X-ray diffraction and absorption techniques to the study of H+/MnO2 alkaline batteries. The two complementary in situ techniques are described. Investigation of the electrochemical insertion and deinsertion of H+ has been made through its influence on the evolution of the crystallographic structure of γ-MnO2, while investigation of the transfer of e has been undertaken through the variation of the oxidation state of the manganese during the discharging and charging process of a battery. New insights in the understanding of the mechanisms of proton insertion and charge transfer into γ-MnO2 are discussed.

scholarly journals A Continuous Flow System for In-Situ XANES Measurements of Change in Oxidation State of Ce (III) to Ce (IV)

2005 ◽  
Vol 6 (1) ◽  
pp. 65-67 ◽  
Author(s):  
Toshihiko Ohnuki ◽  
Takahiro Yoshida ◽  
Takuya Nankawa ◽  
Takuo Ozaki ◽  
Naofumi Kozai ◽  
...  
Keyword(s):  
Oxidation State ◽  
Continuous Flow ◽  
Flow System ◽  
Continuous Flow System ◽  
In Situ Xanes

scholarly journals A compact furnace for in situ X-ray absorption spectroscopy: design, fabrication and study of cationic oxidation states in Pr6O11 and NiO

2021 ◽  
Vol 28 (2) ◽  
pp. 455-460
Author(s):  
Suchinda Sattayaporn ◽  
Somboonsup Rodporn ◽  
Pinit Kidkhunthod ◽  
Narong Chanlek ◽  
Chutarat Yonchai ◽  
...  
Keyword(s):  
Oxidation State ◽  
Absorption Spectroscopy ◽  
Heating Temperature ◽  
Reduction Process ◽  
Oxidation States ◽  
Quartz Tube ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

A well designed compact furnace has been designed for in situ X-ray absorption spectroscopy (XAS). It enables various heat ramps from 300 K to 1473 K. The furnace consists of heaters, a quartz tube, a circulated refrigerator and a power controller. It can generate ohmic heating via an induction process with tantalum filaments. The maximum heating rate exceeds 20 K min−1. A quartz tube with gas feedthroughs allows the mixing of gases and adjustment of the flow rate. The use of this compact furnace allows in situ XAS investigations to be carried out in transmission or fluorescence modes under controlled temperature and atmosphere. Moreover, the furnace is compact, light and well compatible to XAS. The furnace was used to study cationic oxidation states in Pr6O11 and NiO compounds under elevated temperature and reduced atmosphere using the in situ X-ray absorption near-edge structure (XANES) technique at beamline 5.2 SUT-NANOTEC-SLRI of the Synchrotron Light Research Institute, Thailand. At room temperature, Pr6O11 contains a mixture of Pr3+ and Pr4+ cations, resulting in an average oxidation state of +3.67. In situ XANES spectra of Pr (L 3-edge) show that the oxidation state of Pr4+ cations was totally reduced to +3.00 at 1273 K under H2 atmosphere. Considering NiO, Ni2+ species were present under ambient conditions. At 573 K, the reduction process of Ni2+ occurred. The Ni0/Ni2+ ratio increased linearly with respect to the heating temperature. Finally, the reduction process of Ni2+ was completely finished at 770 K.

scholarly journals Magnetic Properties and Redox State of Impact Glasses: A Review and New Case Studies from Siberia

Geosciences ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 225
Author(s):  
Pierre Rochette ◽  
Natalia S. Bezaeva ◽  
Andrei Kosterov ◽  
Jérôme Gattacceca ◽  
Victor L. Masaitis ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Oxidation State ◽  
Redox State ◽  
Magnetic Anomalies ◽  
Formation Processes ◽  
X Ray ◽  
Ferromagnetic Component ◽  
High Velocity Impacts ◽  
Superparamagnetic State

High velocity impacts produce melts that solidify as ejected or in-situ glasses. We provide a review of their peculiar magnetic properties, as well as a new detailed study of four glasses from Siberia: El’gygytgyn, Popigai, urengoites, and South-Ural glass (on a total of 24 different craters or strewn-fields). Two types of behavior appear: 1) purely paramagnetic with ferromagnetic impurities at most of the order of 10 ppm; this corresponds to the five tektite strewn-fields (including the new one from Belize), urengoites, and Darwin glass. Oxidation state, based in particular on X-ray spectroscopy, is mostly restricted to Fe2+; 2) variable and up to strong ferromagnetic component, up to the 1 wt % range, mostly due to substituted magnetite often in superparamagnetic state. Accordingly, bulk oxidation state is intermediate between Fe2+ and Fe3+, although metallic iron, hematite, and pyrrhotite are sometimes encountered. Various applications of these magnetic properties are reviewed in the field of paleomagnetism, magnetic anomalies, recognition of glass origin, and formation processes.

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