Global aromaticity in a partially fused 8-porphyrin nanoring
Template-directed synthesis has been used to prepare a fully π-conjugated cyclic porphyrin octamer, composed of both β,meso,β-edge-fused porphyrin tape units and butadiyne-linked porphyrins. The UV–vis–NIR spectra of this partially fused nanoring show that π-conjugation extends around the whole macr...
| Main Authors: | , , , , |
|---|---|
| Format: | Journal article |
| Language: | English |
| Published: |
American Chemical Society
2020
|
| _version_ | 1826260545523679232 |
|---|---|
| author | Kopp, SM Gotfredsen, H Deng, J-R Claridge, TDW Anderson, HL |
| author_facet | Kopp, SM Gotfredsen, H Deng, J-R Claridge, TDW Anderson, HL |
| author_sort | Kopp, SM |
| collection | OXFORD |
| description | Template-directed synthesis has been used to prepare a fully π-conjugated cyclic porphyrin octamer, composed of both β,meso,β-edge-fused porphyrin tape units and butadiyne-linked porphyrins. The UV–vis–NIR spectra of this partially fused nanoring show that π-conjugation extends around the whole macrocycle, and that it has a smaller HOMO–LUMO gap than its all-butadiyne-linked analogue, as predicted by TD-DFT calculations. The 1H NMR shifts of the bound templates confirm the disrupted aromaticity of the edge-fused porphyrins in the neutral nanoring. NMR oxidation titrations reveal the presence of a global paratropic ring current in its 4+ and 8+ oxidation states and of a global diatropic ring current in the 6+ state of the partially fused ring. The paratropic ring current in the 4+ oxidation state is about four times stronger than that in the all-butadiyne-linked cyclic octamer complex, whereas the diatropic current in the 6+ state is about 40% weaker. Two isomeric K-shaped tetrapyridyl templates with trifluoromethyl substituents at different positions were used to probe the distribution of the ring current in the 4+, 6+, and 8+ oxidation states by 19F NMR, demonstrating that the ring currents are global and homogeneous. |
| first_indexed | 2024-03-06T19:07:20Z |
| format | Journal article |
| id | oxford-uuid:15996899-b288-4385-b53e-d8891a96ddb0 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T19:07:20Z |
| publishDate | 2020 |
| publisher | American Chemical Society |
| record_format | dspace |
| spelling | oxford-uuid:15996899-b288-4385-b53e-d8891a96ddb02022-03-26T10:26:25ZGlobal aromaticity in a partially fused 8-porphyrin nanoringJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:15996899-b288-4385-b53e-d8891a96ddb0EnglishSymplectic ElementsAmerican Chemical Society2020Kopp, SMGotfredsen, HDeng, J-RClaridge, TDWAnderson, HLTemplate-directed synthesis has been used to prepare a fully π-conjugated cyclic porphyrin octamer, composed of both β,meso,β-edge-fused porphyrin tape units and butadiyne-linked porphyrins. The UV–vis–NIR spectra of this partially fused nanoring show that π-conjugation extends around the whole macrocycle, and that it has a smaller HOMO–LUMO gap than its all-butadiyne-linked analogue, as predicted by TD-DFT calculations. The 1H NMR shifts of the bound templates confirm the disrupted aromaticity of the edge-fused porphyrins in the neutral nanoring. NMR oxidation titrations reveal the presence of a global paratropic ring current in its 4+ and 8+ oxidation states and of a global diatropic ring current in the 6+ state of the partially fused ring. The paratropic ring current in the 4+ oxidation state is about four times stronger than that in the all-butadiyne-linked cyclic octamer complex, whereas the diatropic current in the 6+ state is about 40% weaker. Two isomeric K-shaped tetrapyridyl templates with trifluoromethyl substituents at different positions were used to probe the distribution of the ring current in the 4+, 6+, and 8+ oxidation states by 19F NMR, demonstrating that the ring currents are global and homogeneous. |
| spellingShingle | Kopp, SM Gotfredsen, H Deng, J-R Claridge, TDW Anderson, HL Global aromaticity in a partially fused 8-porphyrin nanoring |
| title | Global aromaticity in a partially fused 8-porphyrin nanoring |
| title_full | Global aromaticity in a partially fused 8-porphyrin nanoring |
| title_fullStr | Global aromaticity in a partially fused 8-porphyrin nanoring |
| title_full_unstemmed | Global aromaticity in a partially fused 8-porphyrin nanoring |
| title_short | Global aromaticity in a partially fused 8-porphyrin nanoring |
| title_sort | global aromaticity in a partially fused 8 porphyrin nanoring |
| work_keys_str_mv | AT koppsm globalaromaticityinapartiallyfused8porphyrinnanoring AT gotfredsenh globalaromaticityinapartiallyfused8porphyrinnanoring AT dengjr globalaromaticityinapartiallyfused8porphyrinnanoring AT claridgetdw globalaromaticityinapartiallyfused8porphyrinnanoring AT andersonhl globalaromaticityinapartiallyfused8porphyrinnanoring |