Pyrrole Annulation Controls Protonation-Induced Topology Switching in π-Extended Core-Modified Figure-of-Eight Hexaphyrins
Abstract
Two π-extended core-modified figure-of-eight [38]hexaphyrins(6.1.1.6.1.1) exhibiting strong NIR absorption were synthesized to examine how pyrrole annulation controls protonation-induced topology switching and aromaticity modulation. The nonannulated system undergoes protonation-driven planarization with enhanced global aromaticity, whereas β-annulation rigidifies the macrocycle and preserves the figure-of-eight topology upon protonation. TD-DFT calculations, aromaticity descriptors, and ring-current analysis show that annulation localizes the electronic response and that the NIR Q-type bands arise mainly from local excitations rather than global aromaticity.
Fields of Study & Subjects
Synthesis and Properties of Aromatic Compounds
Porphyrin and Phthalocyanine Chemistry
Supramolecular Self-Assembly in Materials
Publication details
- Journal / source
- Organic Letters
- Publisher
- American Chemical Society (ACS)
- Volume
- 28
- Issue
- 25
- Pages
- 8071–8076
- Publication date
- 11 June 2026
- Language
- EN