ISBN 978-3-8439-5087-9

978-3-8439-5087-9, Reihe Bioanorganische Chemie

Niels Klein
Isomeric Oxocorroles and the Corresponding Biometal Complexes

331 Seiten, Dissertation Technische Universität Braunschweig (2022), Softcover, A5

Zusammenfassung / Abstract

This work presents the synthesis and analytics of novel porphyrinoids and their biometal complexes. A general strategy to isomeric oxocorrole free-base compounds, copper and iron complexes could be established.

Oxocorroles are characterized by a carbonyl group in a meso-position, whereby the two isomers 5- and 10-oxocorroles were of special interest. The synthesis was limited to distinct meso-unsubstituted and beta-substituted species. The 5-oxocorroles were prepared by a direct oxygenation approach using selenium dioxide with the corresponding corrole as precursor. The reaction was selective at the 5-position of the corrole scaffold. The preparation of the 10-oxocorrole was more elaborate and various approaches were investigated. The ring synthesis by the 10-oxobilane approach was successfully applied as a general method to the desired oxocorrole compounds. The biometal complexes were obtained by a single metalation step using copper and iron salts.

All isomeric oxocorroles were confirmed as large, stable, antiaromatic, conjugated macrocycles like norcorroles or isophlorins. The investigation of the antiaromaticity of the free-base compounds was of high importance. Numerous methods like UV-VIS and NMR spectroscopy, X-ray crystallography and DFT calculations were used to confirm the antiaromaticity of the isomeric oxocorroles and were applied for a direct comparison between them, too.

The biometal complexes were analysed by various spectroscopic methods, too, whereby the focus was especially on the analyses of the spin and oxidation states.