Ulm, Univ., Diss., 2000.

Tübingen, Univ., Diplomarb., 2005.

Stuttgart, Univ., Diss., 2004.

Stuttgart, Univ., Diss., 2006.

Thesis (doctoral)--Lunds universitet, Malmö, 1981. / Includes the author's five published papers. Extra t.p. with thesis statement inserted.

Universiẗat, Diss., 2000--Dortmund. / Dateiformat: PDF.

Regensburg, Univ., Diss., 2009.

No description available.

In this diploma thesis a detailed investigation of the step-by-step reduction mechanism of cone-mono-, di-, tri and tetranitrocalix[4]arenes (in non-aqueous DMF) is presented. The intramolecular interaction of reducible (and reduced) centers and its consequences for the geometry of the starting molecule was discussed including the character of radicalic intermediates and their spin state. It was found, that the electrochemically generated radical anions of nitrogroups (unlike their starting electroneutral state) can act as ligands. Therefore, a study of complex formation equilibria of cone-tetranitrocalix[4]arenes with alkali metal cations followed. The possible use of a "stereoelectrochemical" approach (the relationship between geometry or conformation of the molecule and its electrochemical data) was demonstrated in describing and explaining conformational and electrochemical differences between two isomeric dinitrocalix[4]arenes. Finally, a new series of 1,3-alt-tetranitrothiacalix[4]arenes was electrochemically characterized and compared with the "classic" calixarene derivatives. Key words: electrochemistry, calixarenes, stereochemistry

Fuel cells are a promising alternate power source of electricity. Despite of sig- nificant improvement that was reached by research throughout recent decades, the technology is not still ready to large scale commercial use. The catalyst of fuel cell (FC) should be still investigated due to fact that the only reliable functional catalyst is Platinum, a noble and expensive metal, which makes the use of this technology not competitive. In this thesis, investigation of Platinum doped ceria catalyst and its modification prepared by physical technique of deposition which is magnetron sputtering is presented. The catalyst was studied using standard sur- face analytic techniques (PES, SEM, AFM, XANES) as well as electrochemical measurement (CV, PEIS). The principal part of this thesis reports direct analyses of catalyst in fuel cell using an individually designed fuel cell test station. Con- sidering the high power density (PD) about 1 W cm−2 and substantially higher specific power per gram of Platinum (SP) 1.6 kW mg−1 in comparison with com- mercial Pt-Ru/Pt-C reference catalyst and additionally the relatively longtime stability, the sputtered Platinum doped cerium oxide based catalyst was found a suitable catalyst for PEM FC. Moreover, possible substitution of Pt and CeO2 by other elements was shown. Beside of...