A new class of conjugated macrocycle, the cyclo[4]thiophene[4]furan hexyl ester (C4TE4FE), is reported. This cycle consists of alternating α‐linked thiophene‐3‐ester and furan‐3‐ester repeat units, and was prepared in a single step using Suzuki–Miyaura cross‐coupling of a 2‐(thiophen‐2‐yl)furan monomer. The ester side groups help promote a
Macrocycle formation that relies upon
- NSF-PAR ID:
- 10434537
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Chemistry – A European Journal
- Volume:
- 29
- Issue:
- 50
- ISSN:
- 0947-6539
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract syn conformation of the heterocycles, which enables formation of the macrocycle. Cyclic voltammetry studies revealed that C4TE4FE could undergo multiple oxidations, so treatment with SbCl5resulted in formation of the [C4TE4FE]2+dication. Computational work, paired with1H NMR spectroscopy of the dication, revealed that the cycle becomes globally aromatic upon 2e−oxidation, as the annulene pathway along the outer ring becomes Hückel aromatic. The change in ring current for the cycle upon oxidation was clear from1H NMR spectroscopy, as the protons of the thiophene and furan rings shifted downfield by nearly 6 ppm. This work highlights the potential of sequence control in furan‐based macrocycles to tune electronic properties. -
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