Notizen: Monitoring Chemical Reactions by Variable Temperature Photoelectron Spectroscopy. A New Thermal Reaction

1975 ◽  
Vol 30 (12) ◽  
pp. 1785-1786
Author(s):  
Werner Schäfer ◽  
Armin Schweig
Keyword(s):  
Chemical Reactions ◽  
Hydrogen Sulphide ◽  
Photoelectron Spectroscopy ◽  
Variable Temperature ◽  
Low Pressure ◽  
Thermal Reaction

Abstract Variable temperature photoelectron (vtpe) spectroscopy is applied to ethane-1,2-dithiol. Thereby it is shown that this molecule thermally reacts to thiirane and hydrogen sulphide at the very low pressure applied in the pe experiment.

Tautomerism of pyrazoline-5-thione and triazoline-5-thione studied by variable temperature photoelectron spectroscopy

1983 ◽  
Vol 61 (6) ◽  
pp. 1197-1203 ◽  
Author(s):  
Claude Guimon ◽  
Geneviève Pfister-Guillouzo ◽  
Mlkael Begtrup
Keyword(s):  
Gaseous Phase ◽  
Photoelectron Spectroscopy ◽  
Variable Temperature ◽  
Thermal Isomerization ◽  
Photoelectron Spectra ◽  
Planar Form ◽  
Mndo Calculations

Photoelectron spectra at variable temperatures demonstrate that the rate of thermal isomerization of pyrazoline-5-thione (1a) into methylthiopyrazole(s) in the gaseous phase is metal catalysed. Similar isomerizations of triazolethione (2a and 3a) are at best only slightly so.Furthermore, photoelectron spectra and MNDO calculations show that gaseous methylthiopyrazoles (1b and 1c) and methylthiotriazoles (2b and 2c) exist predominantly in planar form for the b isomer and in nonplanar form for the c isomer. The ΔH0 for the rotameric equilibria is 2.7–4.2 kJ•mol−1.

scholarly journals Sonochemical Reaction of Bifunctional Molecules on Silicon (111) Hydride Surface

Molecules ◽  
2021 ◽  
Vol 26 (20) ◽  
pp. 6166
Author(s):  
Serge Ismael Zida ◽  
Yue-Der Lin ◽  
Yit Lung Khung
Keyword(s):  
Photoelectron Spectroscopy ◽  
Lone Pair ◽  
Thermal Reaction ◽  
Silicon Hydride ◽  
Force Microscopy ◽  
Bifunctional Molecules ◽  
Bond Breakage ◽  
Sonochemical Reaction ◽  
Grafting From ◽  
P Type

While the sonochemical grafting of molecules on silicon hydride surface to form stable Si–C bond via hydrosilylation has been previously described, the susceptibility towards nucleophilic functional groups during the sonochemical reaction process remains unclear. In this work, a competitive study between a well-established thermal reaction and sonochemical reaction of nucleophilic molecules (cyclopropylamine and 3-Butyn-1-ol) was performed on p-type silicon hydride (111) surfaces. The nature of surface grafting from these reactions was examined through contact angle measurements, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Cyclopropylamine, being a sensitive radical clock, did not experience any ring-opening events. This suggested that either the Si–H may not have undergone homolysis as reported previously under sonochemical reaction or that the interaction to the surface hydride via a lone-pair electron coordination bond was reversible during the process. On the other hand, silicon back-bond breakage and subsequent surface roughening were observed for 3-Butyn-1-ol at high-temperature grafting (≈150 °C). Interestingly, the sonochemical reaction did not produce appreciable topographical changes to surfaces at the nano scale and the further XPS analysis may suggest Si–C formation. This indicated that while a sonochemical reaction may be indifferent towards nucleophilic groups, the surface was more reactive towards unsaturated carbons. To the best of the author’s knowledge, this is the first attempt at elucidating the underlying reactivity mechanisms of nucleophilic groups and unsaturated carbon bonds during sonochemical reaction of silicon hydride surfaces.

X-ray photoelectron spectroscopy study of the metal/polymer contacts involving aluminum and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) derivatives

2003 ◽  
Vol 18 (5) ◽  
pp. 1219-1226 ◽  
Author(s):  
S. K. M. Jönsson ◽  
W. R. Salaneck ◽  
M. Fahlman
Keyword(s):  
Chemical Reactions ◽  
Photoelectron Spectroscopy ◽  
Interfacial Layer ◽  
Model Systems ◽  
Reaction Site ◽  
Benzenesulfonic Acid ◽  
Spectroscopy Study ◽  
X Ray ◽  
Thin Region ◽  
Metal Polymer

The contact formed between aluminum and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) (PEDOT-PSS) derivatives was studied using x-ray photoelectron spectroscopy. The aluminum/PEDOT-PSS contact contains an interfacial layer formed by chemical reactions between aluminum and mainly poly(styrenesulfonic acid) (PSSH). These chemical interactions were studied with the help of model systems (PSSH, benzenesulfonic acid, and sodium benzenesulfonate). The preferred reaction site of aluminum is the SO3− and SO3−H+ groups of the PSS chains, giving rise to C-S-Al(-O) and C-O-Al species. The resulting contact formed consists of an insulating aluminum/PSS layer and a thin region of partially dedoped PEDOT-PSS. There is significant aluminum diffusion into films of the highly conducting form of PEDOT-PSS that have substantially less PSS at the surface. Hence, no (thick) aluminum/PSS layer is formed in this case, though the PEDOT chains close to the aluminum contact will still be partially dedoped as for the aluminum/PEDOT-PSS case.

scholarly journals Functionalization of Neutral Polypropylene by Using Low Pressure Plasma Treatment: Effects on Surface Characteristics and Adhesion Properties

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 202 ◽  
Author(s):  
Chiara Mandolfino ◽  
Enrico Lertora ◽  
Carla Gambaro ◽  
Marco Pizzorni
Keyword(s):  
Surface Morphology ◽  
Photoelectron Spectroscopy ◽  
Polymeric Materials ◽  
Low Pressure ◽  
Contact Angles ◽  
Bonded Joints ◽  
Water Contact ◽  
Adhesion Properties ◽  
Pressure Plasma ◽  
Low Pressure Plasma

Polyolefins are considered among the most difficult polymeric materials to treat because they have poor adhesive properties and high chemical barrier responses. In this paper, an in-depth study is reported for the low pressure plasma (LPP) treatment of neutral polypropylene to improve adhesion properties. Changes in wettability, chemical species, surface morphology and roughness of the polypropylene surfaces were evaluated by water contact angle measurement, X-ray photoelectron spectroscopy and, furthermore, atomic force microscopy (AFM). Finally, the bonded joints were subjected to tensile tests, in order to evaluate the practical effect of changes in adhesion properties. The results indicate that plasma is an effective treatment for the surface preparation of polypropylene for the creation of bonded joints: contact angles decreased significantly depending on the plasma-parameter setup, surface morphology was also found to vary with plasma power, exposure time and working gas.

Cycloalkylidenselenoketene durch Pyrolyse von 1,2,3-Selenadiazolen — Untersuchungen mit der temperaturabhängigen PE-Spektroskopie und Matrix-IR-Spektroskopie [1]

1984 ◽  
Vol 39 (11) ◽  
pp. 1536-1540 ◽  
Author(s):  
Reinhard Schulz ◽  
Armin Schweig
Keyword(s):  
Liquid Phase ◽  
Ir Spectroscopy ◽  
Ir Spectra ◽  
Gas Phase ◽  
Photoelectron Spectroscopy ◽  
Variable Temperature ◽  
Matrix Ir Spectroscopy

Abstract The gas-phase pyrolysis of cyclohexeno-1,2,3-selenadiazole and cycloocteno-1,2,3-selenadiazole has been investigated by variable temperature photoelectron spectroscopy and matrix IR spectroscopy. The ring contracted, highly reactive products cyclopentylidenselenoketene (cyclopentylidenmethanselone) and cycloheptylidenselenoketene (cycloheptylidenmethanselone) - which had not been found in liquid phase thermolysis experiments - have been detected. Additionally HeI photoelectron and IR spectra of analogous ketenes and thioketenes are presented for comparative reasons.

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