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Push-Pull Quinoidal Porphyrins

Lookup NU author(s): Emeritus Professor Bill CleggORCiD



This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0).


A family of push-pull quinoidal porphyrin monomers has been prepared from a meso-formyl porphyrin by bromination,thioacetal formation, palladium-catalyzed coupling with malononitrile and oxidation with DDQ. Attempts at extending thissynthesis to a push-pull quinoidal/cumulenic porphyrin dimer were not successful. The crystal structures of the quinoidalporphyrins indicate that there is no significant contribution from singlet biradical or zwitterionic resonance forms. Thecrystal structure of an ethyne-linked porphyrin dimer shows that the torsion angle between the porphyrin units is onlyabout 3°, in keeping with crystallographic results on related compounds, but contrasting with the torsion angle of about35° predicted by computational studies. The free-base quinoidal porphyrin monomers form tightly π-stacked layerstructures, despite their curved geometries and bulky aryl substituents.

Publication metadata

Author(s): Smith MJ, Blake IM, Clegg W, Anderson HL

Publication type: Article

Publication status: Published

Journal: Organic and Biomolecular Chemistry

Year: 2018

Volume: 16

Issue: 19

Pages: 3648-3654

Print publication date: 21/05/2018

Online publication date: 24/04/2018

Acceptance date: 24/04/2018

Date deposited: 28/02/2018

ISSN (print): 1477-0520

ISSN (electronic): 1477-0539

Publisher: Royal Society of Chemistry


DOI: 10.1039/C8OB00491A


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