Kinetics of adsorption of poly(vinylimidazole) (PVI) onto copper surfaces investigated by quartz crystal microbalance studies

Organic corrosion inhibitors offer a huge potential of lowering product cost and manufacturing complexity in printed circuit board industry. Up to now, there is no reliable and fast method available to classify materials according to their ability to prevent copper from corrosion based on kinetic data of adsorption. We investigated the potential of the recently presented fast impedance-scanning quartz microbalance (FIS-QCM) to perform such studies. We selected poly(vinylimidazole) (PVI) that is known for its excellent ability to prevent copper from corrosion. However, kinetics and free energy of adsorption of PVI were never investigated. This paper presents the results of these studies. Reliable kinetic data were obtained, and the measurements show also the excellent frequency stability of this device that enables the detection of very small changes in resonance behaviour of the sensor quartz crystal, even below 1?Hz.     

Die Bildfehler 3. Ordnung der kurzen schwachen rein elektrischen Elektronen-Einzellinse

Zeitschrift für Physik A Hadrons and nuclei - Im Grenzfall der kurzen schwachen rein elektrischen Einzellinse nehmen die Gleichungen für die elektronenoptischen Bildfehler eine...     

Flash vacuum pyrolysis of azolylacroleins and azolylbutadienes

2-Aryl-5-acroleinyl-1,2,3,4-tetrazoles (1a–d) and 2-aryl-5-butadienyl-1,2,3,4-tetrazoles (1e–g) were subjected to flash vacuum pyrolysis. Acroleinyl derivatives resulted in nitrogen extrusion to give nitrilimines followed by ring closure to give the corresponding indazoles 3a–d in good yields. On the other hand, butadiene derivatives underwent ring fragmentation to give p-substituted anilines without formation of the expected indazoles. Differences between thermal behaviour of 2-(4-chlorophenyl)-5-acroleinyl-1,2,3,4-tetrazole (1c) and 1-(4-chlorophenyl)-4-acroleinyl-1,2,3-triazole (2) were studied in details. DFT calculations have been used to examine the nitrilimine and carbene nature of the intermediates involved in the thermal reactions of azolyl derivatives.     

A novel ambident reactivity of azolylacroleins

Reaction of azolylacroleins with phosphoranes bearing a conjugated double bond was found to yield either azolyltrienes in a Wittig reaction, or to undergo cyclization to a dihydrobenzene containing the azole substituent. Transformation with an aza-Wittig reagent gave tetrazolylpyridines. The ambident reactivity was found to be dependent on the substituent of the phosphorane, which was rationalized by ab initio (DFT) calculation of the atomic charges of the reaction centres.     

First Suzuki-Miyaura type cross-coupling of ortho-azidobromobenzene with arylboronic acids and its application to the synthesis of fused aromatic indole-heterocycles

A short synthesis of some fused indole-heterocycles has been achieved via Pd-catalyzed cross-coupling reactions between azido-2-bromobenzene and arylboronic acids and subsequent thermally induced nitrene insertion. Additionally, 4-amino-α-carboline, a versatile intermediate toward grossularine analogs has also been prepared by Suzuki-Miyaura cross-coupling of 4-pivaloylaminopyridine-3-boronic acid with 2-bromoaniline, followed by simple functional group transformations.     

Synthesis of novel cyclopropylic sulfones and sulfonamides acting as glucokinase activators

A synthetic route towards cyclopropylic compounds, which act as glucokinase activators is described herein. The present synthesis gives easy and rapid access to a wide variety of either sulfones or sulfonamides starting from readily available late-stage intermediates.