Ramanspektroskopische Untersuchung der Esterfaltung in Überschallexpansionen, Oder: Wie man bei der Suche nach der Haarnadel im Esterhaufen fünf auf einmal findet
Raman spectroscopic investigaton of the folding of esters in supersonic expansions, Or: While looking for a hairpin in an esterstack, how to find five at once
by Maxim Gawrilow
Date of Examination:2022-03-22
Date of issue:2022-06-29
Advisor:Prof. Dr. Martin A. Suhm
Referee:Prof. Dr. Martin A. Suhm
Referee:Prof. Dr. Jörg Behler
Referee:Prof. Dr. Vasily Moshnyaga
Referee:Prof. Dr. Ricardo Mata
Referee:Prof. Dr. Sven Schneider
Referee:Prof. Dr. Burkhard Geil
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Abstract
English
The conformational preference of linear alkyl chains with an ester group in the center was investigated using Raman spectroscopy in supersonic expansions. Like alkanes, short esters prefer a stretched conformation, but beyond a critical chain length a hairpin-like conformation dominates due to intramolecular dispersive attraction. This turnover point was determined by combining experimental results with quantum chemical calculations. As part of the analysis, a rigorous characterisation of experimental Raman intensities for the setup was performed. For better comparability between calculated and experimental vibrational spectra a simulation of the rotational broadening was developed.
Keywords: Raman spectroscopy; Esters; Supersonic Expansion; Dispersive interaction; Conformational preference; Quantum chemical calculations