tripod-Eisen- und tripod-Cobalt-Komplexe mit Acetonitril als Stützliganden (tripod = RCH2C(CH2PPh2)3; R = H, Ph) / tripod-Iron and tripod-Cobalt-Complexes with Acetonitrile as Supporting Ligands (tripod = RCH2C(CH2PPh2)3; R = H, Ph)

1993 ◽  
Vol 48 (12) ◽  
pp. 1707-1714 ◽  
Author(s):  
A. Asam ◽  
B. Janssen ◽  
G. Huttner ◽  
L. Zsolnai ◽  
O. Walter
Keyword(s):  
Cyclic Voltammetry ◽  
Analytical Techniques ◽  
Cobalt Complexes ◽  
X Ray ◽  
Tripod Ligands ◽  
Reversible Reduction

The tripod ligands RCH2C(CH2PPh2)3 react with (CH3CN)6Fe(BF4)2 to yield the tripod-Fe(II) complexes RCH2C(CH2PPh2)3Fe(CH3CN)3(BF4)2 (R = H, la; R = Ph, lb). The octahedral low spin Fe(II) compounds are shown by cyclic voltammetry to undergo reversible one electron oxidation at +1.47 V (vs. SCE) to give the corresponding Fe(III) derivatives.In a similar way (CH3CN)6Co(BF4)2 reacts with the same tripod ligands to produce the tripod-Co(II) complexes RCH2C(CH2PPh2)3Co(CH3CN)2(BF4)2 (R = H, 2a; R = Ph, 2b). The compounds are paramagnetic (2a, g = 2.123; 2b, g = 2.129). The structure of complex 2b shows that the tripod ligand is facially coordinated with one longer (233.1 pm) and two shorter (about 222 pm) Co—P bonds. Reversible reduction is found for 2a at —0.30 V by cyclic voltammetry. The compounds have been characterized by spectroscopic and analytical techniques including X-ray analyses.

scholarly journals Funktionalisierte tripod-Liganden mit Neopentan-Grundgerüst: Umsetzung von HOCH2C(CH2PR2)3 mit Elektrophilen / Functionalized tripod-Ligands with N eopentane Fram ew ork: R eaction of HOCH2C(CH2PR2)3 with Electrophiles

1995 ◽  
Vol 50 (9) ◽  
pp. 1287-1306 ◽  
Author(s):  
Thomas Seitz ◽  
Alexander Asam ◽  
Gottfried Hüttner ◽  
Olaf Walter ◽  
Laszlo Zsolnai
Keyword(s):  
Hydroxy Group ◽  
Analytical Techniques ◽  
One Pot ◽  
X Ray ◽  
One Pot Synthesis ◽  
Tripod Ligands ◽  
Esterification Reactions ◽  
New Compounds

AbstractSeveral ways to functionalize hydroxy-tripod-ligands (HOCH2C(CH2PR2)3) by activation with electrophiles are presented. The use of carboxylic halides and anhydrides is shown to be generally successful for esterification reactions in a one-pot synthesis starting from the oxetanes O(CH2)2C(CH2PR2)2. Facial coordinaton of the related esters towards iron(II) and molybdenum(O) can be achieved depending on the nature of the phosphane donor groups. If methyliodide or trimethylsilylchloride are used as electrophiles in order to functionalize the hydroxy group in HOCH2C(CH2PR2)3, it is necessary to proctect the phosphane groups by formation of the tris-borane adduct. All new compounds have been fully characterized by the usual analytical techniques as well as by X-ray analyses on selected examples.

Influence of Additives on the Speciation, Morphology, and Nanocrystallinity of Aluminium Electrodeposition

2012 ◽  
Vol 65 (11) ◽  
pp. 1523 ◽  
Author(s):  
Lian Liu ◽  
Xingmei Lu ◽  
Yingjun Cai ◽  
Yong Zheng ◽  
Suojiang Zhang
Keyword(s):  
Cyclic Voltammetry ◽  
Organic Molecules ◽  
Analytical Techniques ◽  
Separation Process ◽  
X Ray Diffraction ◽  
Alkali Metal Chlorides ◽  
Metal Chlorides ◽  
Small Organic Molecules ◽  
X Ray ◽  
Scanning Electron

The effects of various additives, including alkali metal chlorides, rare earth chlorides, small organic molecules, and surfactants on the electrodeposition of aluminium were investigated. The analytical techniques of cyclic voltammetry, potentiostatic coulometry, scanning electron microscope, and X-ray diffraction were applied to determine the speciation, morphology, and nanocrystallinity. It was found that additives significantly influence the morphology and grain parameters of the aluminium deposits. Inorganic additives and macromolecular surfactants play a prominent role in altering the speciation of aluminium. Small organic molecules (including surfactants) with simple structures have almost no effect on the aluminium separation process, but have a role in densification and homogenisation. In addition, the grain size can be adjusted after adding various additives, and then nanocrystallinity can be achieved. In conclusion, the effect of additive on the aluminium deposit can be predicted by cyclic voltammetry, which is a clue for smart-design on technological conditions of aluminium electrodeposition.

The redox properties of ferrocenyl-substituted aryl azines

2002 ◽  
Vol 80 (3) ◽  
pp. 250-262 ◽  
Author(s):  
Vittorio A Sauro ◽  
Mark S Workentin
Keyword(s):  
Cyclic Voltammetry ◽  
Radical Anion ◽  
General Characteristic ◽  
Redox Properties ◽  
Quantum Yields ◽  
X Ray ◽  
Long Wavelength ◽  
Fluorescence Quantum Yields ◽  
Reduction Potentials ◽  
Reversible Reduction

A series of ferrocenyl substituted azines (1-Fc/Ar, where Ar = 4-NO2C6H4, 4-CNC6H4, 4-OCH3C6H4, C5H4N, ferrocene, anthracene, and pyrene) were investigated by electrochemical and photochemical techniques. All the 1-Fc/Ar exhibited oxidation waves within 60 mV of each other, consistent with the expected oxidation of the ferrocene moiety. The reduction properties of 1-Fc/Ar is governed by the nature of the Ar substituent. The standard reduction potentials suggest that ferrocene has comparable electron donating abilities as a 4-methoxyphenyl and 4-dimethyl aminophenyl group. The anthracenyl azines exhibit one-electron reversible reduction followed by dimerization of the radical anion resulting in dimerization rate constants (kd) between 5.1 × 104 and 1.5 × 105 M–1 s–1. 1-Fc/Anth and related azines undergo photochemical E/Z isomerization of the C=N bonds to produce E/Z and Z/Z isomers from the thermodynamically most stable E/E form. Fluorescence at 77 K, was observed for these compounds only after long- wavelength irradiation to produce a mixture of E/E, E/Z, and Z/Z isomers. Fluorescence quantum yields of 0.042, 0.090, and 0.176 were determined for 2-Anth/H, 2-Anth/Anth, and 1-Fc/Anth, respectively. The electrochemical, photochemical, and X-ray data suggest that the azine unit is a conjugation "limiter" and may be a general characteristic of azine molecules.Key words: azines, electrochemistry, cyclic voltammetry, reduction, electron transfer.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Layered and ion implantation specimens as possible reference materials for the electron-probe microanalysis

1992 ◽  
Vol 50 (2) ◽  
pp. 1652-1653
Author(s):  
G. Remond ◽  
R.H. Packwood ◽  
C. Gilles ◽  
S. Chryssoulis
Keyword(s):  
Ion Implantation ◽  
Reference Materials ◽  
Analytical Techniques ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
X Ray ◽  
Spatially Resolved ◽  
Analytical Expressions ◽  
Original Approach ◽  
Depth Concentration

Merits and limitations of layered and ion implanted specimens as possible reference materials to calibrate spatially resolved analytical techniques are discussed and illustrated for the case of gold analysis in minerals by means of x-ray spectrometry with the EPMA. To overcome the random heterogeneities of minerals, thin film deposition and ion implantation may offer an original approach to the manufacture of controlled concentration/ distribution reference materials for quantification of trace elements with the same matrix as the unknown.In order to evaluate the accuracy of data obtained by EPMA we have compared measured and calculated x-ray intensities for homogeneous and heterogeneous specimens. Au Lα and Au Mα x-ray intensities were recorded at various electron beam energies, and hence at various sampling depths, for gold coated and gold implanted specimens. X-ray intensity calculations are based on the use of analytical expressions for both the depth ionization Φ (ρz) and the depth concentration C (ρz) distributions respectively.

Anionic and Cationic Redox Processes in β-Li2IrO3 and Their Structural Implications on Electrochemical Cycling in Li-Ion Cell

2019 ◽  
Author(s):  
Paul Pearce ◽  
Gaurav Assat ◽  
Antonella Iadecola ◽  
François Fauth ◽  
Rémi Dedryvère ◽  
...  
Keyword(s):  
Analytical Techniques ◽  
Charge Compensation ◽  
Coupling Mechanism ◽  
Redox Processes ◽  
Positive Electrodes ◽  
X Ray ◽  
Electrochemical Cycling ◽  
Li Ion ◽  
Electrochemical Instability ◽  
High Degree

The recent discovery of anionic redox as a means to increase the energy density of transition metal oxide positive electrodes is now a well established approach in the Li-ion battery field. However, the science behind this new phenomenon pertaining to various Li-rich materials is still debated. Thus, it is of paramount importance to develop a robust set of analytical techniques to address this issue. Herein, we use a suite of synchrotron-based X-ray spectroscopies as well as diffraction techniques to thoroughly characterize the different redox processes taking place in a model Li-rich compound, the tridimentional hyperhoneycomb β-Li2IrO3. We clearly establish that the reversible removal of Li+ from this compound is associated to a previously described reductive coupling mechanism and the formation of the M-(O-O) and M-(O-O)* states. We further show that the respective contributions to these states determine the spectroscopic response for both Ir L3-edge X-ray absorption spectroscopy (XAS) and X-ray photoemissions spectroscopy (XPS). Although the high covalency and the robust tridimentional structure of this compound enable a high degree of reversibile delithiation, we found that pushing the limits of this charge compensation mechanism has significant effects on the local as well as average structure, leading to electrochemical instability over cycling and voltage decay. Overall, this work highlights the practical limits to which anionic redox can be exploited and sheds some light on the nature of the oxidized species formed in certain lithium-rich compounds.<br>

Anionic and Cationic Redox Processes in β-Li2IrO3 and Their Structural Implications on Electrochemical Cycling in Li-Ion Cell

2019 ◽  
Author(s):  
Paul Pearce ◽  
Gaurav Assat ◽  
Antonella Iadecola ◽  
François Fauth ◽  
Rémi Dedryvère ◽  
...  
Keyword(s):  
Analytical Techniques ◽  
Charge Compensation ◽  
Coupling Mechanism ◽  
Redox Processes ◽  
Positive Electrodes ◽  
X Ray ◽  
Electrochemical Cycling ◽  
Li Ion ◽  
Electrochemical Instability ◽  
High Degree

The recent discovery of anionic redox as a means to increase the energy density of transition metal oxide positive electrodes is now a well established approach in the Li-ion battery field. However, the science behind this new phenomenon pertaining to various Li-rich materials is still debated. Thus, it is of paramount importance to develop a robust set of analytical techniques to address this issue. Herein, we use a suite of synchrotron-based X-ray spectroscopies as well as diffraction techniques to thoroughly characterize the different redox processes taking place in a model Li-rich compound, the tridimentional hyperhoneycomb β-Li2IrO3. We clearly establish that the reversible removal of Li+ from this compound is associated to a previously described reductive coupling mechanism and the formation of the M-(O-O) and M-(O-O)* states. We further show that the respective contributions to these states determine the spectroscopic response for both Ir L3-edge X-ray absorption spectroscopy (XAS) and X-ray photoemissions spectroscopy (XPS). Although the high covalency and the robust tridimentional structure of this compound enable a high degree of reversibile delithiation, we found that pushing the limits of this charge compensation mechanism has significant effects on the local as well as average structure, leading to electrochemical instability over cycling and voltage decay. Overall, this work highlights the practical limits to which anionic redox can be exploited and sheds some light on the nature of the oxidized species formed in certain lithium-rich compounds.<br>

Major and Trace Elements in the Humic Acid

2018 ◽  
Author(s):  
Zoltán Kis ◽  
Katalin Gméling ◽  
Tímea Kocsis ◽  
János Osán ◽  
Mihály András Pocsai ◽  
...  
Keyword(s):  
Trace Elements ◽  
Humic Acid ◽  
Activation Analysis ◽  
Analytical Techniques ◽  
Major And Trace Elements ◽  
Prompt Gamma Activation Analysis ◽  
Prompt Gamma ◽  
Gamma Activation ◽  
X Ray ◽  
Precise Analysis

We present precise analysis of major and trace elements of the humic acid. We used three different element analytical techniques in our investigations as prompt-gamma activation analysis (PGAA), neutron activation analysis (NAA) and X-ray fluorescence (XRF) analysis was carried out. We identified 42 elements in our sample.

X-Ray Tomography for Electronic Packages

2000 ◽  
Author(s):  
Deepak Goyal
Keyword(s):  
3D Imaging ◽  
Development Time ◽  
Analytical Techniques ◽  
Electronic Packages ◽  
X Ray ◽  
Imaging Capability ◽  
Imaging Results ◽  
Key Drivers ◽  
Analytical Tools ◽  
Non Destructive

Abstract Next generation assembly/package development challenges are primarily increased interconnect complexity and density with ever shorter development time. The results of this trend present some distinct challenges for the analytical tools/techniques to support this technical roadmap. The key challenge in the analytical tools/techniques is the development of non-destructive imaging for improved time to information. This paper will present the key drivers for the non-destructive imaging, results of literature search and evaluation of key analytical techniques currently available. Based on these studies requirements of a 3D imaging capability will be discussed. Critical breakthroughs required for development of such a capability are also summarized.

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