Beiträge zur Chemie der Pyrrolpigmente, XXXVI [1] Zur anaeroben Photochemie von 21.24 - Diinethy 1 - aetiobiIi verdin -IV -γ / On the Chemistry of Pyrrole Pigments, XXXVI [1] On the Anaerobic Photochemistry of 21,24-Dimethyl-aetiobiliverdin-IV -γ
Open Access
- 1 March 1980
- journal article
- Published by Walter de Gruyter GmbH in Zeitschrift für Naturforschung B
- Vol. 35 (3) , 376-380
- https://doi.org/10.1515/znb-1980-0322
Abstract
21,24-Dimithylaetiobiliverdin-IV-γ was prepared via excessive methylation of aetiobili. verdin-IV-γ. Its configuration could be established using 1H NMR methods. Photoisomerisation yields the (E,Z,Z) and (E,Z,E) diastereomers which means that the selectivity observed in photoisomerisation of bilatrienes-abc can be removed by making the ligands of the lactame moiety adjacent to exocyclic double bonds nearly equal. The torsional angles at the methine single bonds are approximatly equal in the three diastereomers resulting in much the same UV-VIS spectra. The obviously strong distortion of the conjugated chromophor allows for the deceleration of certain radiationless deexcitation paths thereby allowing for photoisomerisations in homogenous solution.Keywords
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