Monatshefte für Chemie und verwandte Teile anderer Wissenschaften

In the present study, electrocatalytic oxidation of hydrazine was examined by both cyclic voltammetry and amperometry methods at a disposable, poly(alizarin red S) modified pencil graphite electrode (poly(ALS)/PGE) for the first time. Electrochemical behaviors of both bare PGE and poly(ALS)/PGE were tested by cyclic voltammetry towards 1.0 mM hydrazine in pH 9.0 Britton–Robinson buffer solution. Cyclic voltammograms showed that the oxidation peak potential of hydrazine at PGE (+ 0.70 V) was significantly reduced at poly(ALS)/PGE (+ 0.35 V) and also, a significant increment in oxidation current was observed. The recorded CVs confirmed that poly(ALS) shows high electrocatalytic effect towards oxidation of hydrazine. Secondly, the effects of monomer concentration, cycle number used in electropolymerization step and pH value of supporting solution on oxidation current of hydrazine were also optimized and found to be 1.0 mM, 5 cycle, and pH 10.0, respectively. The designed sensor shows a wide linear response range between 1.0 and 600 µM hydrazine with a LOD of 0.28 µM and a sensitivity of 833 µA mM−1 cm−2. The selectivity property of the poly(ALS)/PGE was tested in presence of various interferences. Applicability studies of the poly(ALS)/PGE were also performed on different water samples and high recovery values (95–108%) were obtained.

Electrochemical behaviour of zopiclone was investigated on glassy carbon electrode in static and rotation disc arrangement. Strong influence of kinetics and adsorption phenomena on the electrode processes was proved by voltammetric techniques. Controlled potential electrolysis in off-line and on-line combination with tandem mass spectrometry was employed for investigation of the products of electrochemical oxidation. N-Desmethyl zopiclone was identified and three other oxidation products formed by an introduction of one or two oxygen atom(s) to the molecule of zopiclone (including zopiclone N-oxide) were characterized. Based on mass spectrometric investigation of those products, piperazine moiety was proved as a target of electrochemical oxidation of zopiclone. Since N-desmethyl zopiclone and zopiclone N-oxide have been reported as products of enzymatic metabolism of the drug, the combination of electrochemistry with mass spectrometry may be considered as a reliable tool for simulation of some metabolic transformations.

Zwei verschiedene Monoenoläther von 1,3-Cyclohexandionen werden mit Sulfanilamid-Natrium zu den N1-vinylogen Acylderivaten umgesetzt. Mit 4n-Salzsäure lagern sich diese in die N4-vinylogen Acylderivate um.

Al-doped copper oxide (Al-CuO) nano-structures experimentally have shown a higher sensitivity and response toward the carbon monoxide (CO) gas compared to the pristine CuO. We applied the B3LYP-gCP-D3 density functional method to illustrate the origin of this phenomenon in terms of charge transport, density of states, charge transfers, energetic as well as electronic analyses. The adsorption energy of CO on the CuO or Al-CuO nano-cluster was predicted to be − 50.9 or − 112.4 kJ/mol. The adsorption of CO adsorption did not impact on the electronic characteristics of the pristine CuO. The higher charge transfer from CO to the Al-CuO significantly destabilized its highest occupied molecular orbital level, which largely decreases the band gap. Thus, the electrical conductance implicitly increased which is responsible for the sensing mechanism. A short recovery time of 6.3 ms and a sensing response of 10.27 were predicted for the Al-CuO. We showed that the Al-CuO might be considered as a work-function-type sensor for CO gas in addition to electronic detection. The analysis of AIM shows that the C–Cu bond is more covalent compared to the C–Al bond.

The stretching force constant correlates satisfactorily with theWiberg's bond order,K(N-O)=11.791 [p(N-O)]−9.565, with a correlation coefficient of 0.958, for nitrogen—oxygen systems.

Alkyl and alkenyl quinolines (so-called “Pyo-substances”) and theirN-oxides were isolated fromPseudomonas aeruginosa. Structures proposed earlier could be confirmed; a new representative (“Pyo V”) is described.