Thienylquinonoidal Porphyrins and Hexaphyrins with Singlet Diradical Ground States

Koji Naoda, Daiki Shimizu, Jun Oh Kim, Ko Furukawa, Dongho Kim, Atsuhiro Osuka

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

To explore stable organic diradicaloids, meso-thienylquinonoid-substituted porphyrins Pn and hexaphyrins Hn, where “n” denotes the number of thienyl units in the meso-substituents, were synthesized. P0 was identified as a closed-shell quinonoid, whereas P1 was shown to possess significant diradical character with diradical character index (y) of 0.99 and quite small singlet-triplet energy gap (ΔES-T) of −0.13 kcal mol−1. P1 was certainly stable, allowing its isolation, but decomposed gradually in solution. In the hexaphyrin series, it was shown that H0 and H1 were closed-shell quinonoids, but H2 was a highly stable diradicaloid with y=0.85 and ΔES-T of −3.72 kcal mol−1. The high stability of H2 was ascribed to effective spin delocalization over the entire conjugated network. Characteristically, H2 displays an intense absorption band in NIR region at λmax=1175 nm with molar absorption coefficient (ϵ) of 8.81×104 mol−1 L cm−1, a narrow HOMO–LUMO gap of 0.69 eV, and nine reversible redox potential waves.

Original languageEnglish
Pages (from-to)8969-8979
Number of pages11
JournalChemistry - A European Journal
Volume23
Issue number37
DOIs
Publication statusPublished - 2017 Jan 1

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Porphyrins
Ground state
Absorption spectra
Energy gap
Oxidation-Reduction

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Organic Chemistry

Cite this

Naoda, Koji ; Shimizu, Daiki ; Kim, Jun Oh ; Furukawa, Ko ; Kim, Dongho ; Osuka, Atsuhiro. / Thienylquinonoidal Porphyrins and Hexaphyrins with Singlet Diradical Ground States. In: Chemistry - A European Journal. 2017 ; Vol. 23, No. 37. pp. 8969-8979.
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Thienylquinonoidal Porphyrins and Hexaphyrins with Singlet Diradical Ground States. / Naoda, Koji; Shimizu, Daiki; Kim, Jun Oh; Furukawa, Ko; Kim, Dongho; Osuka, Atsuhiro.

In: Chemistry - A European Journal, Vol. 23, No. 37, 01.01.2017, p. 8969-8979.

Research output: Contribution to journalArticle

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AU - Osuka, Atsuhiro

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