Organocobalt B12 models: axial ligand effects on the structural and coordination chemistry of cobaloximes

To experimentally identify both clay sorption sites and sorption equilibria and to understand the retention mechanisms at a molecular level, we have characterized the structure of hexavalent uraniu...

Use of spectroscopic techniques for uranium(VI)/montmorillonite interaction modeling.

Formation, structure (stereochimie et stereodynamique), et donnees de spectroscopie RMN des composes du titre

Molecular and electronic structure of penta- and hexacoordinate silicon compounds

Presently, research in layered transition metal dichalcogenides (TMDs) for numerous electrochemical applications have largely focused on Group 6 TMDs, especially MoS2 and WS2, whereas TMDs belonging to other groups are relatively unexplored. This work unravels the electrochemistry of Group 10 TMDs: specifically PtS2, PtSe2, and PtTe2. Here, the inherent electroactivities of these Pt dichalcogenides and the effectiveness of electrochemical activation on their charge transfer and electrocatalytic properties are thoroughly examined. By performing density functional theory (DFT) calculations, the electrochemical and electrocatalytic behaviors of the Pt dichalcogenides are elucidated. The charge transfer and electrocatalytic attributes of the Pt dichalcogenides are strongly associated with their electronic structures. In terms of charge transfer, electrochemical activation has been successful for all Pt dichalcogenides as evident in the faster heterogeneous electron transfer (HET) rates observed in electrochemically reduced Pt dichalcogenides. Interestingly, the hydrogen evolution reaction (HER) performance of the Pt dichalcogenides adheres to a trend of PtTe2 > PtSe2 > PtS2 whereby the HER catalytic property increases down the chalcogen group. Importantly, the DFT study shows this correlation to their electronic property in which PtS2 is semiconducting, PtSe2is semimetallic, and PtTe2 is metallic. Furthermore, Pt dichalcogenides are effectively activated for HER. Distinct electronic structures of Pt dichalcogenides account for their different responses to electrochemical activation. Among all activated Pt dichalcogenides, PtS2 shows most accentuated improvement as a HER electrocatalyst with an exceptional 50% decline in HER overpotential. Knowledge on Pt dichalcogenides provides valuable insights in the field of TMD electrochemistry, in particular, for the currently underrepresented Group 10 TMDs.

Layered Platinum Dichalcogenides (PtS2, PtSe2, and PtTe2) Electrocatalysis: Monotonic Dependence on the Chalcogen Size

Publisher Summary This chapter discusses the chemistry of nitrogen fixation and models for the reactions of nitrogenase The interest in nitrogen fixation for the inorganic chemist is to try to understand, using simple compounds, what nature does so comparatively effortlessly within the enzyme, nitrogenase This is of particular value considering the increasing demand for nitrogenous fertilizers, and the vast industrial expenditure of energy in producing ammonia The literature of chemical nitrogen fixation, even excluding that related to the Haber process, is now considerable The mechanisms of reaction of coordinated dinitrogen are a matter of dispute There are several proposals extant, chemical and biological, and these are espoused by their progenitors with varying degrees of fervor However, there is now sufficient chemistry available for us to make preliminary judgments concerning the validity of the various proposals

The Chemistry of Nitrogen Fixation and Models for The Reactions of Nitrogenase

Influence parameters. A quantitative characteristics of the capacity of ligands to exert mutual influence

Structure of Ni(II)-creatinine complex species formed in non-aqueous media

Molecular nitrogen as a ligand. A study of dinitrogen complexes of transition metals, diazocompounds, and azides by x-ray photoelectron spectroscopy

The electronic structure of the magnetic semiconductors Mn x Cd1 − x GeAs2 and Mn x Zn1 − x GeAs2, where x = 0, 0.0625, and 0.125, is calculated by the method of electron density functional in the plane-wave basis. Features of participation of Mn3d-electrons in the chemical bond are revealed. It is found that their role in the chemical bond with group-V element depends on the group-II element and the concentration of the magnetic dopant.

Electronic structure and chemical bonds in the magnetic semiconductors MnxCd1 − x GeAs2 and MnxZn1 − x GeAs2

The elemental and ionic surface compositions of (TeO2)0.8 (WO3)0.2 and (TeO2)0.7(WO3)0.2(La2O3)0.1 glasses annealed at different temperatures and bombarded with Ar+ ions for various lengths of time have been determined using x-ray photoelectron spectroscopy. The results indicate that the surface layer of the glasses contains tellurium ions in two chemical states, which differ markedly in concentration. The oxidation state of one type of tellurium ion is close to that in TeO, \(E_{b_1 } \) (Te 3d5/2)= 574.0 eV, and the oxidation state of the other is close to that in TeO2 [\(E_{b_2 } \) (Te 3d5/2) = 576.6 eV. In all of the samples, tungsten is in an oxidation state close to 6+ (WO3), and the oxidation state of lanthanum is 3+ (La2O3). Ar+-ion milling for 4 min using an argon gun markedly reduces the surface hydrocarbon contamination but has, for the most part, an insignificant effect on the characteristics of the XPS spectra. Increasing the ion milling time leads to the formation of new states of both tellurium and tungsten ions. The oxygen ions in the glass samples studied are chemically equivalent and differ markedly in oxidation state from those in the constituent metal oxides. The metal—oxygen bond length evaluated from the O 1s binding energy in the glasses is RM-O = 0.192 nm.

V. I. Nefedov

Papers

Influence parameters. A quantitative characteristics of the capacity of ligands to exert mutual influence

Structure of Ni(II)-creatinine complex species formed in non-aqueous media

Molecular nitrogen as a ligand. A study of dinitrogen complexes of transition metals, diazocompounds, and azides by x-ray photoelectron spectroscopy

Electronic structure and chemical bonds in the magnetic semiconductors MnxCd1 − x GeAs2 and MnxZn1 − x GeAs2

X-ray photoelectron study of Te-W-O and Te-W-La-O glasses