Engineering conjugation in para-phenylene-bridged porphyrin tapes
We report the synthesis of 7 new para-phenylene-bridged zinc porphyrin dimers, five of which were characterized by single-crystal X-ray analysis. A variety of links were tested for holding the para-phenylene bridges in π-conjugation with the porphyrins, and the natures of these restraining links str...
| Main Authors: | , , , , , , , , , , , , |
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| Format: | Journal article |
| Language: | English |
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2012
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| _version_ | 1826271376615407616 |
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| author | Pawlicki, M Morisue, M Davis, N McLean, D Haley, J Beuerman, E Drobizhev, M Rebane, A Thompson, A Pascu, S Accorsi, G Armaroli, N Anderson, H |
| author_facet | Pawlicki, M Morisue, M Davis, N McLean, D Haley, J Beuerman, E Drobizhev, M Rebane, A Thompson, A Pascu, S Accorsi, G Armaroli, N Anderson, H |
| author_sort | Pawlicki, M |
| collection | OXFORD |
| description | We report the synthesis of 7 new para-phenylene-bridged zinc porphyrin dimers, five of which were characterized by single-crystal X-ray analysis. A variety of links were tested for holding the para-phenylene bridges in π-conjugation with the porphyrins, and the natures of these restraining links strongly influence the properties of the porphyrin dimers. The keto-linked dimer exhibits a long-lived singlet excited state and strong fluorescence at 960 nm (1.7% quantum yield) in contrast to most previously reported conjugated porphyrin tapes, which are essentially non-emissive. Replacement of the cross-conjugated keto links by directly conjugated C-C bonds eradicates the fluorescence and shifts the absorption maximum to 1077 nm. On the other hand, replacement of the keto links with non-conjugated CPh 2 links confers fluorescence at 736 nm (10% quantum yield) and results in remarkably similar one- and two-photon absorption behavior to that of meso-meso ethynylene-bridged porphyrin dimers (peak two-photon cross section: 7,300 GM at 878 nm). Cross-conjugated keto links do more than just hold the para-phenylene bridge coplanar with the porphyrins; they reduce the HOMO-LUMO gap, although to a lesser extent than direct π-conjugated links. Planarized para-phenylene- bridged porphyrin dimers provide insights into the relationship between previously investigated classes of conjugated porphyrin oligomers, and they open up possibilities for the synthesis of new types of near-IR two-photon absorbing dyes. |
| first_indexed | 2024-03-06T21:55:42Z |
| format | Journal article |
| id | oxford-uuid:4cdbf927-71d5-4a53-90eb-ac540896e8bf |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T21:55:42Z |
| publishDate | 2012 |
| record_format | dspace |
| spelling | oxford-uuid:4cdbf927-71d5-4a53-90eb-ac540896e8bf2022-03-26T15:51:54ZEngineering conjugation in para-phenylene-bridged porphyrin tapesJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:4cdbf927-71d5-4a53-90eb-ac540896e8bfEnglishSymplectic Elements at Oxford2012Pawlicki, MMorisue, MDavis, NMcLean, DHaley, JBeuerman, EDrobizhev, MRebane, AThompson, APascu, SAccorsi, GArmaroli, NAnderson, HWe report the synthesis of 7 new para-phenylene-bridged zinc porphyrin dimers, five of which were characterized by single-crystal X-ray analysis. A variety of links were tested for holding the para-phenylene bridges in π-conjugation with the porphyrins, and the natures of these restraining links strongly influence the properties of the porphyrin dimers. The keto-linked dimer exhibits a long-lived singlet excited state and strong fluorescence at 960 nm (1.7% quantum yield) in contrast to most previously reported conjugated porphyrin tapes, which are essentially non-emissive. Replacement of the cross-conjugated keto links by directly conjugated C-C bonds eradicates the fluorescence and shifts the absorption maximum to 1077 nm. On the other hand, replacement of the keto links with non-conjugated CPh 2 links confers fluorescence at 736 nm (10% quantum yield) and results in remarkably similar one- and two-photon absorption behavior to that of meso-meso ethynylene-bridged porphyrin dimers (peak two-photon cross section: 7,300 GM at 878 nm). Cross-conjugated keto links do more than just hold the para-phenylene bridge coplanar with the porphyrins; they reduce the HOMO-LUMO gap, although to a lesser extent than direct π-conjugated links. Planarized para-phenylene- bridged porphyrin dimers provide insights into the relationship between previously investigated classes of conjugated porphyrin oligomers, and they open up possibilities for the synthesis of new types of near-IR two-photon absorbing dyes. |
| spellingShingle | Pawlicki, M Morisue, M Davis, N McLean, D Haley, J Beuerman, E Drobizhev, M Rebane, A Thompson, A Pascu, S Accorsi, G Armaroli, N Anderson, H Engineering conjugation in para-phenylene-bridged porphyrin tapes |
| title | Engineering conjugation in para-phenylene-bridged porphyrin tapes |
| title_full | Engineering conjugation in para-phenylene-bridged porphyrin tapes |
| title_fullStr | Engineering conjugation in para-phenylene-bridged porphyrin tapes |
| title_full_unstemmed | Engineering conjugation in para-phenylene-bridged porphyrin tapes |
| title_short | Engineering conjugation in para-phenylene-bridged porphyrin tapes |
| title_sort | engineering conjugation in para phenylene bridged porphyrin tapes |
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