Oxidative Pyrrole Exchange and meso Pyrrylation – Unexpected Reactions of Open‐Chain Tetrapyrrolic 2,2′‐Bidipyrrins |
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Authors: | Martin Bröring Prof Dr Stephan Link Meike Cordes Carsten D Brandt |
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Institution: | 1. Marburg, Fachbereich Chemie der Philipps‐Universit?tFachbereich Chemie, Philipps‐Universit?t, Hans‐Meerwein‐Stra?e, D‐35043 Marburg/Germany, Fax: int. (0)6421 2825356;2. Marburg, Fachbereich Chemie der Philipps‐Universit?t |
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Abstract: | A new hydrogen terminated 2,2′‐bidipyrrin ligand was prepared from a bipyrrole dialdehyde and 3,4‐diethylpyrrole by a POCl3 induced condensation and isolated as the nickel(II) chelate. Unexpectedly a side reaction occured when base‐deficient and aerobic conditions were chosen in the metalation step. This side reaction led to a novel pentapyrrolic nickel(II) complex with one externally bound pyrrole ring. Further studies showed that the reactions of 2,2′‐bidipyrrins with 3,4‐diethyl‐ or 2,3,4‐trimethylpyrrole and an oxidant resulted in a stepwise exchange of the terminal pyrrole moieties and, in the former case, the introduction of one additional pyrrole ring into one of the two meso positions of the open‐chain tetrapyrrole. |
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Keywords: | Nickel Redox transformations N ligands Helicity Porphyrinoids |
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