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Updated: Sep 23, 2025

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Electrochemical and optoelectronic properties of terthiophene- and bithiophene-based polybenzofulvene derivatives

Fabrizia Fabrizi de Biani1, Annalisa Reale1, Vincenzo Razzano1

  • 1Dipartimento di Biotecnologie, Chimica e Farmacia and European Research Centre for Drug Discovery and Development, Università degli Studi di Siena Via Aldo Moro 2 53100 Siena Italy andrea.cappelli@unisi.it +39 0577 234320.

RSC Advances
|May 11, 2022
PubMed

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Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
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The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
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