Electronic structure of (MePh3P)2[NiII(bdtCl2)2]·2(CH3)2SO and (MePh3P)[NiIII(bdtCl2)2] (bdtCl2 = 3,6-dichlorobenzene-1,2-dithiolate)

2021 ◽  
Vol 77 (6) ◽  
Author(s):  
Julia Adamko Koziskova ◽  
Yu-Sheng Chen ◽  
Su-Yin Grass ◽  
Yu-Chun Chuang ◽  
I-Jui Hsu ◽  
...  
Keyword(s):  
Electronic Structure ◽  
High Resolution ◽  
Theoretical Calculations ◽  
Nickel Complexes ◽  
Oxidation States ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Absorption ◽  
Bond Character ◽  
Density Modeling

High-resolution X-ray diffraction experiments, theoretical calculations and atom-specific X-ray absorption experiments were used to investigate two nickel complexes, (MePh3P)2[NiII(bdtCl2)2]·2(CH3)2SO [complex (1)] and (MePh3P)[NiIII(bdtCl2)2] [complex (2)]. Combining the techniques of nickel K- and sulfur K-edge X-ray absorption spectroscopy with high-resolution X-ray charge density modeling, together with theoretical calculations, the actual oxidation states of the central Ni atoms in these two complexes are investigated. Ni ions in two complexes are clearly in different oxidation states: the Ni ion of complex (1) is formally NiII; that of complex (2) should be formally NiIII, yet it is best described as a combination of Ni2+ and Ni3+, due to the involvement of the non-innocent ligand in the Ni—L bond. A detailed description of Ni—S bond character (σ,π) is presented.

scholarly journals Electronic Structure of BiFe1−xMnxO3Thin Films Investigated by X-Ray Absorption Spectroscopy

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Abduleziz Ablat ◽  
Emin Muhemmed ◽  
Cheng Si ◽  
Jiaou Wang ◽  
Haijie Qian ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Absorption Spectroscopy ◽  
Causal Relation ◽  
Structural Phase ◽  
X Ray Diffraction ◽  
Doping Amount ◽  
X Ray ◽  
Mn Content ◽  
Mn Substitution ◽  
X Ray Absorption

Multiferroic polycrystalline BiFe1-xMnxO3(0≤x≤0.3) thin films have been prepared on the Pt(111)/Ti/SiO2/Si(100) substrates by pulsed laser deposition method. The influence of Mn substitution on the electronic structure and magnetic properties has been studied. X-ray diffraction spectroscopy shows that Mn substitution slightly modulates crystal structure of the BiFe1-xMnxO3system within the same structural phase. According to FeLedge X ray absorption spectroscopy, Fe ions are found to be formally trivalent for doping amountxin BiFe1-xMnxO3. The enhanced magnetization by increasing Mn content is attributed to an alternation degree of hybridization between Fe 3d-O 2pand Mn 3d-O 2porbitals, basing on the carefully examined FeLand OKedge X-ray absorption spectroscopy. The crystal structural and the electronic structural results show a causal relation between them by demonstrating intrinsic mutual dependence between respective variations.

Charge density studies of 3dmetal (Ni/Cu) complexes with a non-innocent ligand

2017 ◽  
Vol 73 (4) ◽  
pp. 634-642 ◽  
Author(s):  
Yu-Chun Chuang ◽  
Chou-Fu Sheu ◽  
Gene-Hsiang Lee ◽  
Yu-Sheng Chen ◽  
Yu Wang
Keyword(s):  
High Resolution ◽  
Charge Density ◽  
Reduced Form ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxidation Reduction ◽  
Square Planar ◽  
Square Planar Complexes ◽  
X Ray Absorption ◽  
Cu Complexes

High-resolution X-ray diffraction experiments and atom-specific X-ray absorption experiments are applied to investigate a series of square planar complexes with the non-innocent ligand of maleonitriledithiolate (mnt), [S2C2(CN)2]z−, containingM—S bonds. Four complexes of (PyH)z[M(mnt)2]z−, whereM= Ni or Cu,z= 2 or 1 and PyH+= C5NH6+, were studied in order to clarify whether such one-electron oxidation–reduction, [M(mnt)2]2−/[M(mnt)2]1−, is taking place at the metal or the ligand site. Combining the techniques of metalK-,L-edge and SK-edge X-ray absorption spectroscopy with high-resolution X-ray charge density studies, it is unambiguously demonstrated that the electron redox reaction is ligand based and metal based for Ni and Cu pairs, respectively. The bonding characters in terms of topological properties associated with the bond critical points are compared between the oxidized form [ML]−and the reduced form [ML]2−. In the case of Ni complexes, the formal oxidation state of Ni remains as Ni2+and each mnt ligand carries a 2− charge in [Ni(mnt)2]2−, but only one of the ligands is formally oxidized in [Ni(mnt)2]1−. In contrast, in the case of Cu complexes, the mnt remains as 2− in both complexes, but the formal oxidation states of the metal are Cu2+and Cu3+. Bond characterizations andd-orbital populations will be presented. The complementary results of XAS, XRD and DFT calculations will be discussed. The conclusion on the redox reactions in these complexes can be firmly established.

EFFECT OF HEAT TREATMENT ON MICROSTRUCTURE AND MAGNETOSTRICTIVE PROPERTY OF MELT-SPUN Fe85Ga15 RIBBONS

2013 ◽  
Vol 27 (30) ◽  
pp. 1350174 ◽  
Author(s):  
HAO LIU ◽  
HAIOU WANG ◽  
MENGXIONG CAO ◽  
WEISHI TAN ◽  
YANGGUANG SHI ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Fine Structure ◽  
High Resolution ◽  
Nearest Neighbor ◽  
Annealed Sample ◽  
X Ray Diffraction ◽  
X Ray ◽  
Absorption Fine ◽  
Melt Spun ◽  
X Ray Absorption

In order to study the microstructure of Fe – Ga alloy, Fe 85 Ga 15 ribbons prepared with different wheel velocity were studied by high resolution X-ray diffraction (HRXRD) and extend X-ray absorption fine structure (EXAFS). HRXRD patterns showed that only disordered A 2 phase was observed in as-cast Fe 85 Ga 15 alloy. A modified- DO 3 phase was detected in all of the melt spun samples. The HRXRD associated with EXAFS results indicated that Ga atoms were located as second-nearest neighbor along [100] orientation. A little DO 3 phase was found in ribbons annealed at 1000°C under 0.06 MPa Ar atmosphere. The result of magnetostriction measurement revealed that in the ribbon prepared with higher wheel velocity, more modified- DO 3 phase will enhance the magnetostriction. DO 3 phase in the annealed sample will deteriorate the magnetostrictive properties of Fe – Ga ribbons.

Electronic structure of NixTiSe2 (0.05 ≤ x ≤ 0.46) compounds with ordered and disordered Ni

2017 ◽  
Vol 19 (6) ◽  
pp. 4500-4506 ◽  
Author(s):  
A. S. Shkvarin ◽  
Yu. M. Yarmoshenko ◽  
A. I. Merentsov ◽  
Yu. M. Zhukov ◽  
A. A. Titov ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Absorption Spectroscopy ◽  
Theoretical Calculations ◽  
Electronic States ◽  
Intercalation Compounds ◽  
X Ray ◽  
Density Of Electronic States ◽  
X Ray Absorption

The electronic structure of NixTiSe2 intercalation compounds with disordered and ordered Ni atoms is studied using photoelectron, resonant photoelectron and X-ray absorption spectroscopy, theoretical calculations of the X-ray spectra and density of electronic states.

Martensite Transition and Microscopic Magnetism of Epitaxial Ni2MnGa Films

2007 ◽  
Vol 1050 ◽  
Author(s):  
Gerhard Jakob ◽  
Tobias Eichhorn ◽  
Michael Kallmayer ◽  
Hans-Joachim Elmers
Keyword(s):  
Magnetic Circular Dichroism ◽  
Theoretical Calculations ◽  
Magnetic Moments ◽  
Structural Phase ◽  
Absorption Feature ◽  
X Ray Diffraction ◽  
Orbital Contribution ◽  
X Ray ◽  
Transmission Geometry ◽  
X Ray Absorption

AbstractA magnetically induced shape memory effect in Ni2MnGa results in huge magnetostrictive effects of several percent. Using x-ray absorption spectroscopy (XAS) and magnetic circular dichroism (XMCD) we investigated element specific magnetic moments and electronic structure of single crystalline, (110) oriented Ni2MnGa films on a-plane Al2O3 substrates in the austenite and martensite state. The structural phase transition of the samples is evident from temperature dependent x-ray diffraction and magnetization measurements. The Ni XAS differ significantly for temperatures above and below the martensite transition in agreement with published ab-initio calculations. Using XAS in transmission geometry on our thin film samples we observe the corresponding reduction of the absorption feature as predicted by theoretical calculations. The XMCD analysis shows the orbital contribution of the Ni electrons to be responsible for the magnetic anisotropy.

scholarly journals Experimental Investigations of the Interaction of SO2 with MgO

1999 ◽  
Vol 590 ◽  
Author(s):  
Andrea Freitag ◽  
J. A. Rodriguez ◽  
J. Z. Larese
Keyword(s):  
High Resolution ◽  
Film Thickness ◽  
Room Temperature ◽  
Temperature Programmed Desorption ◽  
Experimental Investigations ◽  
X Ray Diffraction ◽  
High Quality ◽  
X Ray ◽  
Temperature Programmed ◽  
X Ray Absorption

ABSTRACTHigh resolution adsorption isotherms, temperature programmed desorption (TPD), x-ray diffraction (XRD) and x-ray absorption near edge spectroscopy (XANES) methods were used to investigate the interaction of SO2 with high quality MgO powders. The results of these investigations indicate that when SO2 is deposited on MgO in monolayer quantities at temperatures near 100K both SO3 and SO4 species form that are not removed by simply pumping on the pre-dosed samples at room temperature. TPD and XANES studies indicate that heating of pre-dosed MgO samples to temperatures above 350 °C is required for full removal of the SO3/SO4 species. XANES measurements made as a function of film thickness indicate for coverages near monolayer completion that the SO4 species form first.

Effects of bond character on the electronic structure of brownmillerite-phase oxides, Ca2B′xFe2−xO5 (B′ = Al, Ga): an X-ray absorption and electron energy loss spectroscopic study

2009 ◽  
Vol 19 (48) ◽  
pp. 9213 ◽  
Author(s):  
Andrew P. Grosvenor ◽  
Farshid Ramezanipour ◽  
Shahab Derakhshan ◽  
Christian Maunders ◽  
Gianluigi A. Botton ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Energy Loss ◽  
Spectroscopic Study ◽  
Electron Energy ◽  
X Ray ◽  
Electron Energy Loss ◽  
X Ray Absorption ◽  
Bond Character

scholarly journals Generation and Reactivity of a NiIII2(μ-1,2-peroxo) Complex

2020 ◽  
Author(s):  
Norman Zhao ◽  
Alexander S. Filatov ◽  
Jiaze Xie ◽  
Ethan A. Hill ◽  
John Anderson
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Oxidation States ◽  
Peroxo Complex ◽  
Intermediate Species ◽  
X Ray Diffraction ◽  
X Ray ◽  
Tetrabutylammonium Chloride ◽  
High Valent ◽  
X Ray Absorption

Ni-based oxide materials are promising candidates for catalyzing the oxygen evolution reaction. The detailed mechanism of water splitting in these systems has been of interest with a goal of understanding the intermediate species vital for catalytic activity. A potential intermediate species prior to release of oxygen is a bridging Ni<sup>III</sup><sub>2</sub>(<i>μ</i>-1,2-peroxo) complex. However, Ni<sub>2</sub>(<i>μ</i>-1,2-peroxo) complexes are rare in general and are unknown with oxidation states higher than Ni<sup>II</sup>. Herein, we report the isolation of such an unusual high-valent species in a Ni<sup>III</sup><sub>2</sub>(<i>μ</i>-1,2-peroxo) complex, which has been characterized using single-crystal X-ray diffraction and X-ray absorption, NMR, and UV-vis spectroscopies. In addition, treatment with excess tetrabutylammonium chloride results in regeneration of the precursor Ni–Cl species, implicating the reversible release of oxygen or a reactive oxygen species. Taken together, this suggests that Ni<sup>III</sup><sub>2</sub>(<i>μ</i>-1,2-peroxo) species are accessible and may be viable intermediates during the oxygen evolution reaction.

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