Estimating Molecular Weights of Organometallics in Solution with Diffusion NMR Techniques
Estimating Molecular Weights of Organometallics in Solution with Diffusion NMR Techniques
von Sebastian Bachmann
Datum der mündl. Prüfung:2017-03-01
Erschienen:2017-03-31
Betreuer:Prof. Dr. Dietmar Stalke
Gutachter:Prof. Dr. Dietmar Stalke
Gutachter:Prof. Dr. Konrad Koszinowski
Gutachter:Prof. Dr. Inke Siewert
Gutachter:Prof. Dr. Ricardo Mata
Gutachter:Prof. Dr. Selvan Jun.Demir
Gutachter:Dr. Michael John
Dateien
Name:Dissertation_Bachmann.pdf
Size:31.8Mb
Format:PDF
Zusammenfassung
Englisch
This PhD thesis focuses on diffusion NMR spectroscopy and the utilisation of the external calibration curve (ECC) diffusion-ordered spectroscopy (DOSY) technique on the estimation of molecular weights of organometallic compounds. The thesis is comprised of three parts. In the first part of this work, improvements of the ECC-DOSY methodology are the main focus. In particular, the limited applicability is adressed by introduction of ECCs for seven additional solvents. Furthermore, theoretical calculations on the limitations of the technique and molecule categorization are performed. Additionally, a software for the prediction of molecular weights is introduced. In the second part of this work, alkali metal cyclopentadienides are investigated with the ECC-DOSY technique in THF and DMSO. In THF they form mostly monomeric contact ion pairs, whereas in DMSO foremost solvent-separated ion pairs are observed. In the final part of this thesis, different ambiguities concerning various organometallic compounds were clarified using DOSY, e.g. for alkyl Grignard reagents.
Keywords: NMR spectroscopy; Organometallics; Alkali Metals; Cyclopentadienides; Grignard; MW estimation; diffusion coefficients; External calibration curves; DOSY; ECC