scholarly journals Rational design of an argon-binding superelectrophilic anion

2019 ◽  
Vol 116 (17) ◽  
pp. 8167-8172 ◽  
Author(s):  
Martin Mayer ◽  
Valentin van Lessen ◽  
Markus Rohdenburg ◽  
Gao-Lei Hou ◽  
Zheng Yang ◽  
...  
Keyword(s):  
Rational Design ◽  
Room Temperature ◽  
Spectroscopic Studies ◽  
Mass Spectrometric ◽  
Bonding Analysis ◽  
Metal Free ◽  
High Level ◽  
Exceptional Stability ◽  
Structurally Stable

Chemically binding to argon (Ar) at room temperature has remained the privilege of the most reactive electrophiles, all of which are cationic (or even dicationic) in nature. Herein, we report a concept for the rational design of anionic superelectrophiles that are composed of a strong electrophilic center firmly embedded in a negatively charged framework of exceptional stability. To validate our concept, we synthesized the percyano-dodecoborate [B12(CN)12]2−, the electronically most stable dianion ever investigated experimentally. It serves as a precursor for the generation of the monoanion [B12(CN)11]−, which indeed spontaneously binds Ar at 298 K. Our mass spectrometric and spectroscopic studies are accompanied by high-level computational investigations including a bonding analysis of the exceptional B-Ar bond. The detection and characterization of this highly reactive, structurally stable anionic superelectrophile starts another chapter in the metal-free activation of particularly inert compounds and elements.

In-Situ Ftir and Mass Spectrometric Studies of Gallium Arsenide Metalorganic Chemical Vapor Deposition: Trimethyl Gallium and Tertiary-Butyl Arsine on GaAs(100)

1990 ◽  
Vol 204 ◽  
Author(s):  
Ananth V. Annapragada ◽  
Klavs F. Jensen
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Spectroscopic Studies ◽  
Mass Spectrometric ◽  
Tertiary Butyl ◽  
Alkyl Groups ◽  
Butyl Radical ◽  
Trimethyl Gallium

ABSTRACTLow pressure (∼10−5 Torr) studies of the adsorption and decomposition of tertiarybutyl arsine (t-BAs) on three different GaAs(100) surfaces (Ga-rich, H-atom treated and high temperature t-BAs treated) are presented. Mass spectrometric studies indicate that the primary gas-phase products of t-BAs decomposition on GaAs(100) are the tertiary-butyl radical and incomplete arsenic hydrides (predominantly AsH2). Infrared spectroscopic studies show that on H-atom treated and high-temperature t-BAs treated surfaces, t-BAs decomposes leaving behind very small quantities of alkyl groups. On Ga-rich surfaces however, significant amounts of alkyl products are observed. The surface species resulting from the adsorption of trimethyl gallium (TMG) are shown to be different at room temperature and high temperature.

Fast Atom Bombardment Mass Spectrometric Analysis of Base Hydrolyzed γ-Lactone

1993 ◽  
Vol 76 (4) ◽  
pp. 913-917
Author(s):  
Randall J Baker
Keyword(s):  
Molecular Structure ◽  
Room Temperature ◽  
Fast Atom Bombardment ◽  
Ion Pairs ◽  
Mass Spectrometric ◽  
Spectrometric Analysis ◽  
Thermally Induced ◽  
Fab Mass Spectrometry ◽  
Hydroxy Carboxylic Acid

Abstract Fast atom bombardment (FAB) mass spectrometry (MS) is used to characterize the γ-hydroxy carboxylic acid (γ-HCa) formed from base hydrolyzed γ-lactone at room temperature. Acidification of this base hydrolyzed solution reconverts the γ-HCa back to γ-lactone. Mass shift differences between tetramethylammonium (TMA+) and Na+ ion-pairs with the anionic γ-HCarboxylate(–) (γ-HC(–)) are used to confirm molecular ion identifications. FAB ionization was required to provide mass characterization of the γ-HCa. Electron ionization (El) MS of the γ-HCa was unsuccessful and reconverted γ-HCa back to γ-lactone because of complete thermally induced dehydration. The present paper suggests structures for El fragmentation that support the molecular structure of γ-lactone.

SYNTHESIS AND CHARACTERIZATION OF LANTHANUM DOPED SODIUM BISMUTH TITANATE

2002 ◽  
Vol 16 (26) ◽  
pp. 1007-1019 ◽  
Author(s):  
M. APARNA ◽  
T. BHIMASANKARAM ◽  
G. S. KUMAR ◽  
G. PRASAD
Keyword(s):  
Phase Transitions ◽  
Room Temperature ◽  
Bismuth Titanate ◽  
Structural Phase ◽  
Spectroscopic Studies ◽  
Synthesis And Characterization ◽  
Structural Phase Transitions ◽  
Frequency Range ◽  
Impedance Data

Impedance spectroscopic studies on polycrystalline sintered discs of lanthanum doped Na 1/2( La x Bi 1-x)1/2 TiO 3 ceramics with x = 0, 0.1, 0.15 and 0.2, have been carried out in the temperature region ranging from room temperature to 550°C and in the frequency range of 100 Hz to 1 MHz. Impedance data is presented in frequency explicit plots and Cole–Cole plots. The relaxation behavior of the charge entities in the above samples is studied as a function of temperature. The structural phase transitions present in the samples showed interesting changes with composition frequency and temperature. An attempt is made to correlate the results obtained to the phase transitions present in the samples.

Characterization of intergranular cuprous oxide in polycrystalline YBa2Cu3O7-x

1988 ◽  
Vol 46 ◽  
pp. 880-881
Author(s):  
Bradley L. Thiel ◽  
Chan Han R. P. ◽  
Kurosky L. C. Hutter ◽  
I. A. Aksay ◽  
Mehmet Sarikaya
Keyword(s):  
Grain Boundary ◽  
Cuprous Oxide ◽  
Room Temperature ◽  
Boundary Phase ◽  
Spectroscopic Techniques ◽  
Transition Width ◽  
Practical Applications ◽  
Thin Foils ◽  
Superconducting Oxides

The identification of extraneous phases is important in understanding of high Tc superconducting oxides. The spectroscopic techniques commonly used in determining the origin of superconductivity (such as RAMAN, XPS, AES, and EXAFS) are surface-sensitive. Hence a grain boundary phase several nanometers thick could produce irrelevant spectroscopic results and cause erroneous conclusions. The intergranular phases present a major technological consideration for practical applications. In this communication we report the identification of a Cu2O grain boundary phase which forms during the sintering of YBa2Cu3O7-x (1:2:3 compound).Samples are prepared using a mixture of Y2O3. CuO, and BaO2 powders dispersed in ethanol for complete mixing. The pellets pressed at 20,000 psi are heated to 950°C at a rate of 5°C per min, held for 1 hr, and cooled at 1°C per min to room temperature. The samples show a Tc of 91K with a transition width of 2K. In order to prevent damage, a low temperature stage is used in milling to prepare thin foils which are then observed, using a liquid nitrogen holder, in a Philips 430T at 300 kV.

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