Allosteric cooperativity and template-directed synthesis with stacked ligands in porphyrin nanorings
The link between allosteric cooperativity and template-directed synthesis has been investigated by studying complexes in which two oligopyridine ligands bind inside a zinc porphyrin nanoring in a stacked arrangement. The binding of a 6-porphyrin nanoring to two tridentate ligands (with s-triazine or...
| Auteurs principaux: | , , , , , , |
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| Format: | Journal article |
| Langue: | English |
| Publié: |
American Chemical Society
2020
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| _version_ | 1826293794413215744 |
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| author | Bols, PS Rickhaus, M Tejerina, L Gotfredsen, H Eriksen, K Jirasek, M Anderson, HL |
| author_facet | Bols, PS Rickhaus, M Tejerina, L Gotfredsen, H Eriksen, K Jirasek, M Anderson, HL |
| author_sort | Bols, PS |
| collection | OXFORD |
| description | The link between allosteric cooperativity and template-directed synthesis has been investigated by studying complexes in which two oligopyridine ligands bind inside a zinc porphyrin nanoring in a stacked arrangement. The binding of a 6-porphyrin nanoring to two tridentate ligands (with s-triazine or benzene cores) occurs with high negative allosteric cooperativity (α ≈ 10-3-10-4). Formation constants for 1:1 and 1:2 complexes were determined by UV-vis-NIR denaturation titration, using pyridine as a competing ligand, and cooperativity factors were confirmed by NMR spectroscopy. The rate constants for formation of the 1:1 and 1:2 complexes are approximately equal, and the negative cooperativity can be attributed to faster dissociation of the 1:2 complex. These tridentate ligands are not effective templates for directing the synthesis of the 6-porphyrin nanoring, in keeping with their negative cooperativity of binding. In contrast, the binding of a 12-porphyrin nanoring to two hexadentate ligands occurs with high positive allosteric cooperativity (α > 40), and the ligand is an effective Vernier template for directing the synthesis of the 12-porphyrin nanoring. This stacked Vernier template approach creates the product in an open circular conformation, which is advantageous for preparing macrocycles that do not easily adopt a figure-of-eight geometry. |
| first_indexed | 2024-03-07T03:35:39Z |
| format | Journal article |
| id | oxford-uuid:bc3249e0-ea82-44e3-b731-5ea91a524170 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T03:35:39Z |
| publishDate | 2020 |
| publisher | American Chemical Society |
| record_format | dspace |
| spelling | oxford-uuid:bc3249e0-ea82-44e3-b731-5ea91a5241702022-03-27T05:22:39ZAllosteric cooperativity and template-directed synthesis with stacked ligands in porphyrin nanoringsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:bc3249e0-ea82-44e3-b731-5ea91a524170EnglishSymplectic ElementsAmerican Chemical Society2020Bols, PSRickhaus, MTejerina, LGotfredsen, HEriksen, KJirasek, MAnderson, HLThe link between allosteric cooperativity and template-directed synthesis has been investigated by studying complexes in which two oligopyridine ligands bind inside a zinc porphyrin nanoring in a stacked arrangement. The binding of a 6-porphyrin nanoring to two tridentate ligands (with s-triazine or benzene cores) occurs with high negative allosteric cooperativity (α ≈ 10-3-10-4). Formation constants for 1:1 and 1:2 complexes were determined by UV-vis-NIR denaturation titration, using pyridine as a competing ligand, and cooperativity factors were confirmed by NMR spectroscopy. The rate constants for formation of the 1:1 and 1:2 complexes are approximately equal, and the negative cooperativity can be attributed to faster dissociation of the 1:2 complex. These tridentate ligands are not effective templates for directing the synthesis of the 6-porphyrin nanoring, in keeping with their negative cooperativity of binding. In contrast, the binding of a 12-porphyrin nanoring to two hexadentate ligands occurs with high positive allosteric cooperativity (α > 40), and the ligand is an effective Vernier template for directing the synthesis of the 12-porphyrin nanoring. This stacked Vernier template approach creates the product in an open circular conformation, which is advantageous for preparing macrocycles that do not easily adopt a figure-of-eight geometry. |
| spellingShingle | Bols, PS Rickhaus, M Tejerina, L Gotfredsen, H Eriksen, K Jirasek, M Anderson, HL Allosteric cooperativity and template-directed synthesis with stacked ligands in porphyrin nanorings |
| title | Allosteric cooperativity and template-directed synthesis with stacked ligands in porphyrin nanorings |
| title_full | Allosteric cooperativity and template-directed synthesis with stacked ligands in porphyrin nanorings |
| title_fullStr | Allosteric cooperativity and template-directed synthesis with stacked ligands in porphyrin nanorings |
| title_full_unstemmed | Allosteric cooperativity and template-directed synthesis with stacked ligands in porphyrin nanorings |
| title_short | Allosteric cooperativity and template-directed synthesis with stacked ligands in porphyrin nanorings |
| title_sort | allosteric cooperativity and template directed synthesis with stacked ligands in porphyrin nanorings |
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