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β-Trioxopyrrocorphins: pyrrocorphins of graded aromaticity
Octaethyltrioxopyrrocorphins unexpectedly show macrocycle-aromatic properties, even though they contain the macrocyclic π-system of the non-aromatic pyrrocorphins (hexahydroporphyrins). Two of the four possible triketone regioisomers were first reported in 1969 by one-pot oxidation of octaethylporph...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
The Royal Society of Chemistry
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8480330/ https://www.ncbi.nlm.nih.gov/pubmed/34603659 http://dx.doi.org/10.1039/d1sc03403k |
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author | Chaudhri, Nivedita Guberman-Pfeffer, Matthew J. Li, Ruoshi Zeller, Matthias Brückner, Christian |
author_facet | Chaudhri, Nivedita Guberman-Pfeffer, Matthew J. Li, Ruoshi Zeller, Matthias Brückner, Christian |
author_sort | Chaudhri, Nivedita |
collection | PubMed |
description | Octaethyltrioxopyrrocorphins unexpectedly show macrocycle-aromatic properties, even though they contain the macrocyclic π-system of the non-aromatic pyrrocorphins (hexahydroporphyrins). Two of the four possible triketone regioisomers were first reported in 1969 by one-pot oxidation of octaethylporphyrin but remained essentially unexplored since. We detail here the targeted preparation of the remaining two triketone isomers and the optical and NMR spectroscopic properties of all isomers. All four regioisomers possess unique electronic properties, including broadly varying degrees of diatropicity that were experimentally determined using (1)H NMR spectroscopy and computationally verified. Structural patterns modulating the aromaticity were recognized. These differences highlight the regioisomerically differentiated influences of the three β-oxo-functionalities. We also present the solid state structure of the two most common isomers (in their free base form or as zinc complexes), allowing further conclusions to be made about the resonance structures present in these triketones. Remarkably, also, the halochromic properties of the triketones differ sharply from those of regular (hydro)porphyrins, providing further support for the proposed 16-membered, 18 π-electron aromatic ring-current. The work conceptually expands the understanding of tris-modified hydroporphyrinoid analogues and the factors that enable and control porphyrinoid aromaticity. |
format | Online Article Text |
id | pubmed-8480330 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | The Royal Society of Chemistry |
record_format | MEDLINE/PubMed |
spelling | pubmed-84803302021-10-01 β-Trioxopyrrocorphins: pyrrocorphins of graded aromaticity Chaudhri, Nivedita Guberman-Pfeffer, Matthew J. Li, Ruoshi Zeller, Matthias Brückner, Christian Chem Sci Chemistry Octaethyltrioxopyrrocorphins unexpectedly show macrocycle-aromatic properties, even though they contain the macrocyclic π-system of the non-aromatic pyrrocorphins (hexahydroporphyrins). Two of the four possible triketone regioisomers were first reported in 1969 by one-pot oxidation of octaethylporphyrin but remained essentially unexplored since. We detail here the targeted preparation of the remaining two triketone isomers and the optical and NMR spectroscopic properties of all isomers. All four regioisomers possess unique electronic properties, including broadly varying degrees of diatropicity that were experimentally determined using (1)H NMR spectroscopy and computationally verified. Structural patterns modulating the aromaticity were recognized. These differences highlight the regioisomerically differentiated influences of the three β-oxo-functionalities. We also present the solid state structure of the two most common isomers (in their free base form or as zinc complexes), allowing further conclusions to be made about the resonance structures present in these triketones. Remarkably, also, the halochromic properties of the triketones differ sharply from those of regular (hydro)porphyrins, providing further support for the proposed 16-membered, 18 π-electron aromatic ring-current. The work conceptually expands the understanding of tris-modified hydroporphyrinoid analogues and the factors that enable and control porphyrinoid aromaticity. The Royal Society of Chemistry 2021-08-20 /pmc/articles/PMC8480330/ /pubmed/34603659 http://dx.doi.org/10.1039/d1sc03403k Text en This journal is © The Royal Society of Chemistry https://creativecommons.org/licenses/by/3.0/ |
spellingShingle | Chemistry Chaudhri, Nivedita Guberman-Pfeffer, Matthew J. Li, Ruoshi Zeller, Matthias Brückner, Christian β-Trioxopyrrocorphins: pyrrocorphins of graded aromaticity |
title | β-Trioxopyrrocorphins: pyrrocorphins of graded aromaticity |
title_full | β-Trioxopyrrocorphins: pyrrocorphins of graded aromaticity |
title_fullStr | β-Trioxopyrrocorphins: pyrrocorphins of graded aromaticity |
title_full_unstemmed | β-Trioxopyrrocorphins: pyrrocorphins of graded aromaticity |
title_short | β-Trioxopyrrocorphins: pyrrocorphins of graded aromaticity |
title_sort | β-trioxopyrrocorphins: pyrrocorphins of graded aromaticity |
topic | Chemistry |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8480330/ https://www.ncbi.nlm.nih.gov/pubmed/34603659 http://dx.doi.org/10.1039/d1sc03403k |
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