Helicene Appended Benzothiadiazoles as Chiral Emitters - Université d'Angers
Article Dans Une Revue (Article De Synthèse) Chemistry - A European Journal Année : 2024

Helicene Appended Benzothiadiazoles as Chiral Emitters

Résumé

A homologous series of 4,7-bis(aryl) substituted benzothiadiazole (BTD) compounds, containing the helicenic derivatives bis([4]helicene), bis([5]helicene) and bis([6]helicene), have been prepared upon a double Suzuki coupling between 3,6-bis(pinacolyl-borane)-BTD and the corresponding bromo-aryl precursors. The single crystal X-ray structure of the bis([4]helicene) compound shows the existence of both helicities (M) and (P) on the same molecule. All the compounds of the series are highly emissive in solution, with quantum yields of the emission ranging from 50 to 91%. The enantiopure compounds (M,M) and (P,P) for the BTDbis([6]helicene) have been prepared from the corresponding enantiopure 2-bromo-[6]helicene 2 precursors. Their chiroptical properties have been investigated in correlation with density functional theory (DFT) calculations, which allowed to confidently assign the absolute configuration of the helicene arms and to characterize the different electronic transitions, including the low energy charge transfer excitation from helicenes to BTD. The enantiomerically pure fluorophores (M,M)-and (P,P)-BTD-bis([6]helicene), which exist in solution as two main conformers, according to the DFT calculations, show CPL activity in solution, with glum factors of ≈ 1.7×10 -3 at em = 525 nm, and also in the solid state, with glum factors of ≈ 1.2×10 -3 in spite of the strong decrease of the quantum efficiency.

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Dates et versions

hal-04676548 , version 1 (23-08-2024)

Identifiants

Citer

Kévin Martin, Tal Aharon, Maurizio Mastropasqua Talamo, Andreas Hauser, Thomas Bürgi, et al.. Helicene Appended Benzothiadiazoles as Chiral Emitters. Chemistry - A European Journal, 2024, 30 (42), ⟨10.1002/chem.202401413⟩. ⟨hal-04676548⟩
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