| | 1 | Author
| Steffen Runge, M. Athias, O. Senge | Requires cookie* | | | Title
| Electron Donor-Acceptor Compounds. Synthesis and Structure of 5-(l,4-Benzoquinone-2-yl)-10,15,20-trialkylporphyrins  | | | | Abstract
| A series of 5-(benzoquinone)-10,15,20-trialkylporphyrins was synthesized via cross conden sation of the respective aldehydes, 2,5-dimethoxybenzaldehyde and pyrrole followed by de-methylation with BBr3 and oxidation with P b 0 2. This method worked reasonably well for compounds bearing the benzoquinone substituent and butyl, isopropyl, 1 -methylpropyl and 2-ethylpropyl residues (2a-d). The free base porphyrin quinones were converted into the zinc(II) complexes (3a-d) all of which showed remarkable stability for porphyrin quinones. The zinc(II) complex 3c bearing isopropyl residues was investigated by X-ray crystallography and showed a supramolecular structure consisting of polymeric chains facilitated by coordina tion of a benzoquinone oxygen to a neighboring zinc(II) center. Attempts to synthesize a 5-(benzoquinone)-10,15,20-tris(terr-butylporphyrin) resulted in the formation of a yellow por-phomethene (4), which could not be oxidized further. A crystal structure analysis of 4, the first for a free base porphomethene, shows an extremely twisted conformation with syn-orientation of the three rm-butyl groups. The results indicate that new methods will have to be developed for the synthesis of nonplanar porphyrin quinones. | | | |
Reference
| Z. Naturforsch. 53b, 1021—1030 (1998); received June 15 1998 | | | |
Published
| 1998 | | | |
Keywords
| Porphyrins, Quinones, Electron Transfer Compounds, Crystal Structure, Conformation | | | |
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| default:Reihe_B/53/ZNB-1998-53b-1021.pdf | | | | Identifier
| ZNB-1998-53b-1021 | | | | Volume
| 53 | |
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