A detailed analysis of the photoemission spectra of basic thioaromatic monolayers on noble metal substrates

Analysis of photoemission spectra of complex thioaromatic self-assembled monolayers (SAMs) requires the knowledge and understanding of such spectra for the basic systems. Keeping this goal in mind, synchrotron-based high-resolution X-ray photoelectron spectroscopy was used to characterize SAMs formed from the simplest thioaromatic compounds, namely thiophenol, 1,1′-biphenyl-4-thiol and 1,1′;4′,1″-terphenyl-4-thiol on evaporated Au(1 1 1) and Ag(1 1 1) substrates. The acquired S 2p and C 1s spectra were analyzed in terms of fine structure and initial and final state effects in the photoemission process. The assignment of the individual spectral features was considered in detail. Conclusions on quality and chemical and structural homogeneity of the investigated SAMs were derived.     

Quantitative theory of living free‐radical polymerization. III. Calculation of copolymerization products' spinodal

The problem of finding conditions of the loss of thermodynamic stability by the reaction system was solved on the basis of the developed theory of living free‐radical copolymerization. The spinodal's calculations were carried out for a significant number of systems differing in the values of kinetic, stoichiometric, and thermodynamic parameters. Analysis of the results of such calculations revealed some regularities in the spinodal curves' behavior and permitted us to classify their possible topological types. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 892–902, 2003     

Sliding spark spectroscopy

Summary A new analytical radiation source combined with fiber optics linked to a diode array detection device with modified software is described. The direct-reading spectrometer simultaneously covers the wavelength range 185–510 nm with a spectral resolution of <1.5 nm. Intense optical emission is observed when positionally stable high-current surface sparks supplied by a pulse-generator with definite discharge parameters (max. 800 Ampere/pulse) are sliding over compact non-conductive materials such as plastics, glasses, quartz filters or powder pellets. Substrate vaporization, ionization and excitation processes in the surface discharge plasma channel generate emission corresponding to neutral and ionic states. The spectra are essentially composed of lines emitted by the electrode material (e.g. copper, silver), from the substrate under investigation, radiation continuum as well as structured background from the surrounding air atmosphere. Due to the occurrence of emission lines of reactive fillers, inorganic pigments and stabilizers, a rapid multi-element screening method is demonstrated. A rapid identification system (mix-up test) of PVC or fire-retardant thermoplastics within one second has been realized from the atomic emission line intensity originating from the sputtered copper electrode material according to its increased volatility in the presence of chlorine (modified Beilstein test).Puls-Plasma-Technik GmbH, Dortmund     

Chiral methylbenzylammonium salts of aryldithiophosphonic acids containing glucofuranose,allofuranose, and galactopyranose diacetonide scaffolds

Abstract

New chiral methylbenzylammonium salts of aryldithiophosphonic acids containing glucofuranose, allofuranose, and galactopyranose diacetonide substituents were obtained using (S)-(–)-α-methylbenzylamine, (R)-(+)-α-methylbenzylamine, and (R,S)-(±)-α-methylbenzylamine. Salts obtained possess antimicrobial activity.     

Metallation regioselective en serie pyridinique: Synthese originale d'amino-2 aroyl-3 pyridines

Lithium diisopropylamide reacts with 2-fluoropyridine at low temperature: regioselectivity is excellent and metallation occurs without side reactions such as nucleophilic attack. 2-Fluoro-3-lithiopyridine is formed and with aldehydes it gives the corresponding fluorinated alcohols which are then selectively oxidized. Halogen substitution using amines leads to various 3-oxoalkyl- or 3-aroyl-2-aminopyridines.     

Alkylation of 3‐Phenyl‐1H‐pyrazolo[4,3‐c] quinoline: Theoretical Analysis of Regioselectivity

The interaction of 3‐phenyl‐1H‐pyrazolo[4.3‐c]quinoline with alkylating agents in the presence of NaH leads mainly to N1‐substituted derivatives. The regioselectivity of the reaction has been studied using AM1 semi‐empirical calculations in the isolated molecule approximation.     

Lipase biosensor for tributyrin and pesticide detection

Potentiometric biosensors based on Candida rugosa lipase was described for the detection of organophosphorus pesticide; methyl-parathion and tributyrin. Lipase was immobilized on the glass electrode by means of a gelatin membrane, which is then cross-linked with glutaraldehyde. The principle of the biosensor is based on the measurement of pH variation which was recorded in millivolts due to the enzymatic hydrolysis of tributyrin to butyric acid. For the inhibitor detection, biosensor responses were measured after pesticide treatment, which caused a drop in enzyme activity because of the irreversible inhibition. Reactivation conditions of the reused enzyme electrodes were also investigated by pyridine-2-aldoxime methiodide (2-PAM). The limit of detection for tributyrin was estimated as 93?µM for lipase sensor within the linear range of 65–455?µM.