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Νέες παραγοντοποιήσεις και μηχανιστικές μελέτες σε αντιδράσεις του φουλερενίου C60 και του αζαφουλερενίου (C59N)2 : εφαρμογή νέων υλικών C60/Al2O3 και C60/SiO2 στην ετερογενή φωτοκατάλυση
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| Identifier | 000278091 | |||
| Title | Νέες παραγοντοποιήσεις και μηχανιστικές μελέτες σε αντιδράσεις του φουλερενίου C60 και του αζαφουλερενίου (C59N)2 : εφαρμογή νέων υλικών C60/Al2O3 και C60/SiO2 στην ετερογενή φωτοκατάλυση | |||
| Alternative Title | New functionalization and mechanistic studies on the reactions of fullerene C60 and azafullerene (C59N)2 : Application of the new C60/Al2O3 and C60/SiO2 surfaces in heterogeneous photocatalysis | |||
| Author | Βουγιουκαλάκης, Γεώργιος Χ | |||
| Thesis advisor | Ορφανόπουλος, Μιχαήλ | |||
| Abstract |
First Chapter: Two novel open-cage fullerene derivatives bearing a 12- membered-ring orifice on the fullerene cage have been isolated. Removal of the NMEM protective group led to the first open cage [60]fullerene derivative without organic addends on the rim of the orifice. Moreover, the addition reaction of the NMEM- ketolactam derivative of [60]fullerene with phenyl, p-Br-phenyl, and p-MeOphenyl hydrazines proceeded regioselectively affording three open-cage fullerene derivatives bearing a 15-membered-ring orifice on the fullerene cage. Both experimental data and theoretical calculations were utilized for the structure determination of the new [60]fullerene adducts. Second Chapter: An efficient reaction between the azafullerene dimer, (C59N)2 and arylalkanes led to the formation of six new azafullerene monoadducts. Furthermore, the reaction between aza[60]fullerene radical and the suitable deuterium labelled arylalkanes has been mechanistically studied. The measured primary and secondary kinetic isotope effects provide strong evidence for a stepwise mechanism, in which the hydrogen atom abstraction occurs in the first, rate-determining step of the reaction, followed by a second, faster, coupling of the two radicals. Third Chapter: The reaction between the C59N+ carbocation and the electron rich aromatic compounds toluene and anisole has been mechanistically studied. The measured intermolecular kinetic isotope effects are consistent with an electrophilic aromatic substitution mechanism in which the arenium cation is formed by electrophilic attack of C59N+ on the aromatic ring in the first step of the reaction, followed by hydrogen abstraction in a rate-determining second step. Additionally, an efficient photoinduced electron transfer reaction, between the C59N+ carbocation and electron rich aromatics, was found to occur for the first time. Fourth Chapter: Deposition of fullerene C60 (2% w/w) on silica and γ- alumina provoked a two orders of magnitude increase of its activity for the liquid phase photooxidation of 2-methyl-2-heptene. The corresponding reaction rate constant was found to be higher in the case where γ-alumina was used as carrier. Ιt was also found that supported C60 sensitizes the photooxidation of alkenes via singlet oxygen and/or electron transfer mechanism, depending on the solvent and the substrate. Fullerene C60 supported on silica or alumina surfaces may be of general utility for laboratory use because a) it photosensitizes the oxidation of a variety of unsaturated compounds, b) the photoreaction is heterogeneous and therefore the catalyst can be easily removed by a simple filtration, c) the heterogeneous nature of the photoreactions overcome solubility problems of the photosensitizers, and d) remains stable at the photooxidation conditions. |
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| Language | Greek | |||
| Issue date | 2004-04-19 | |||
| Collection | School/Department--School of Sciences and Engineering--Department of Chemistry--Doctoral theses | |||
| Type of Work--Doctoral theses | ||||
| Views | 276 | |||
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