Scientific article

Physicochemical and Electronic Properties of Cationic [6]Helicenes: from Chemical and Electrochemical Stabilities to Far-Red (Polarized) Luminescence

Published inChemistry, vol. 22, no. 51, p. 18394-18403
  • The authors have been alerted to an error in the reported electrochemical potential values. See correction in Figure 3 and Table 1.
  • DOI : 10.1002/chem.201603591
  • PMID : 31286594
Publication date2016

The physicochemical properties of cationic dioxa (1), azaoxa (2), and diaza (3) [6]helicenes demonstrate a much higher chemical stability of the diaza adduct 3 (pKR+=20.4, inline image =−0.72 V) compared to its azaoxa 2 (pKR+=15.2, inline image =−0.45 V) and dioxa 1 (pKR+=8.8, inline image =−0.12 V) analogues. The fluorescence of these cationic chromophores is established, and ranges from the orange to the far-red regions. From 1 to 3, a bathochromic shift of the lowest energy transitions (up to 614 nm in acetonitrile) and an enhancement of the fluorescence quantum yields and lifetimes (up to 31 % and 9.8 ns, respectively, at 658 nm) are observed. The triplet quantum yields and circularly polarized luminescence are also reported. Finally, fine tuning of the optical properties of the diaza [6]helicene core is achieved through selective and orthogonal post-functionalization reactions (12 examples, compounds 4–15). The electronic absorption is modulated from the orange to the far-red spectral range (560–731 nm), and fluorescence is observed from 591 to 755 nm with enhanced quantum efficiency up to 70 % (619 nm). The influence of the peripheral auxochrome substituents is rationalized by first-principles calculations.

  • Circularly polarized luminescence
  • Density functional calculations
  • Electrochemistry
  • Fluorescence
  • Helicenes
Citation (ISO format)
BOSSON, Johann et al. Physicochemical and Electronic Properties of Cationic [6]Helicenes: from Chemical and Electrochemical Stabilities to Far-Red (Polarized) Luminescence. In: Chemistry, 2016, vol. 22, n° 51, p. 18394–18403. doi: 10.1002/chem.201901658
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ISSN of the journal0947-6539

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Creation12/12/2016 4:46:00 PM
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