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Acetylene Derivatives of Cationic Diazaoxatriangulenes and Diaza [4]Helicenes ‐ Access to Red Emitters and Planar Chiral Stereochemical Traits

Cationic triangulenes, and related helicenes, constitute a rich class of dyes and fluorophores, usually absorbing and emitting light at low energy, in the orange to red domains. Recently, to broaden the scope of applications, regioselective late‐stage functionalizations on these core moieties have b...

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Autores principales: Ondrisek, Pavol, Elie, Margaux, Pupier, Marion, de Aguirre, Adiran, Poblador‐Bahamonde, Amalia I., Besnard, Céline, Lacour, Jérôme
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9305763/
https://www.ncbi.nlm.nih.gov/pubmed/35040214
http://dx.doi.org/10.1002/chem.202104405
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author Ondrisek, Pavol
Elie, Margaux
Pupier, Marion
de Aguirre, Adiran
Poblador‐Bahamonde, Amalia I.
Besnard, Céline
Lacour, Jérôme
author_facet Ondrisek, Pavol
Elie, Margaux
Pupier, Marion
de Aguirre, Adiran
Poblador‐Bahamonde, Amalia I.
Besnard, Céline
Lacour, Jérôme
author_sort Ondrisek, Pavol
collection PubMed
description Cationic triangulenes, and related helicenes, constitute a rich class of dyes and fluorophores, usually absorbing and emitting light at low energy, in the orange to red domains. Recently, to broaden the scope of applications, regioselective late‐stage functionalizations on these core moieties have been developed. For instance, with the introduction of electron‐donating groups (EDGs), important bathochromic shifts are observed pushing absorptions towards or in the near‐infrared (NIR) spectral domain while emissive properties disappear essentially completely. Herein, to upset this drawback, acetylene derivatives of cationic diazaoxa triangulenes (DAOTA) and [4]helicenes are prepared (16 examples). Contrary to other EDG‐functionalized derivatives, C≡C− functionalized products remain broadly fluorescent, with red‐shifted absorptions (Δλ (abs) up to 25 nm) and emissions (Δλ (em) up to 73 nm, Φ (PL) up to 51 %). Quite interestingly, a general dynamic stereoisomerism phenomenon is evidenced for the compounds derived from achiral DAOTA cores. At low temperature in (1)H NMR spectroscopy (218 K), N−CH(2) protons become diastereotopic with chemical shifts differences (Δδ) as high as +1.64 ppm. The signal coalescence occurs around 273 K with a barrier of ∼12 kcal mol(−1). This phenomenon is due to planar chiral conformations (S (p) and R (p) configurations), induced by the geometry of the alkyl (n‐propyl) side‐chains next to the acetylenic substituents. Ion pairing studies with Δ‐TRISPHAT anion not only confirm the occurrence of the chiral conformations but evidence a moderate but definite asymmetric induction from the chiral anion onto the cations. Finally, DFT calculations offer a valuable insight on the geometries, the corresponding stereodynamics and also on the very large difference in NMR for some of the diastereotopic protons.
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spelling pubmed-93057632022-07-28 Acetylene Derivatives of Cationic Diazaoxatriangulenes and Diaza [4]Helicenes ‐ Access to Red Emitters and Planar Chiral Stereochemical Traits Ondrisek, Pavol Elie, Margaux Pupier, Marion de Aguirre, Adiran Poblador‐Bahamonde, Amalia I. Besnard, Céline Lacour, Jérôme Chemistry Research Articles Cationic triangulenes, and related helicenes, constitute a rich class of dyes and fluorophores, usually absorbing and emitting light at low energy, in the orange to red domains. Recently, to broaden the scope of applications, regioselective late‐stage functionalizations on these core moieties have been developed. For instance, with the introduction of electron‐donating groups (EDGs), important bathochromic shifts are observed pushing absorptions towards or in the near‐infrared (NIR) spectral domain while emissive properties disappear essentially completely. Herein, to upset this drawback, acetylene derivatives of cationic diazaoxa triangulenes (DAOTA) and [4]helicenes are prepared (16 examples). Contrary to other EDG‐functionalized derivatives, C≡C− functionalized products remain broadly fluorescent, with red‐shifted absorptions (Δλ (abs) up to 25 nm) and emissions (Δλ (em) up to 73 nm, Φ (PL) up to 51 %). Quite interestingly, a general dynamic stereoisomerism phenomenon is evidenced for the compounds derived from achiral DAOTA cores. At low temperature in (1)H NMR spectroscopy (218 K), N−CH(2) protons become diastereotopic with chemical shifts differences (Δδ) as high as +1.64 ppm. The signal coalescence occurs around 273 K with a barrier of ∼12 kcal mol(−1). This phenomenon is due to planar chiral conformations (S (p) and R (p) configurations), induced by the geometry of the alkyl (n‐propyl) side‐chains next to the acetylenic substituents. Ion pairing studies with Δ‐TRISPHAT anion not only confirm the occurrence of the chiral conformations but evidence a moderate but definite asymmetric induction from the chiral anion onto the cations. Finally, DFT calculations offer a valuable insight on the geometries, the corresponding stereodynamics and also on the very large difference in NMR for some of the diastereotopic protons. John Wiley and Sons Inc. 2022-02-09 2022-03-10 /pmc/articles/PMC9305763/ /pubmed/35040214 http://dx.doi.org/10.1002/chem.202104405 Text en © 2022 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH https://creativecommons.org/licenses/by-nc/4.0/This is an open access article under the terms of the http://creativecommons.org/licenses/by-nc/4.0/ (https://creativecommons.org/licenses/by-nc/4.0/) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
spellingShingle Research Articles
Ondrisek, Pavol
Elie, Margaux
Pupier, Marion
de Aguirre, Adiran
Poblador‐Bahamonde, Amalia I.
Besnard, Céline
Lacour, Jérôme
Acetylene Derivatives of Cationic Diazaoxatriangulenes and Diaza [4]Helicenes ‐ Access to Red Emitters and Planar Chiral Stereochemical Traits
title Acetylene Derivatives of Cationic Diazaoxatriangulenes and Diaza [4]Helicenes ‐ Access to Red Emitters and Planar Chiral Stereochemical Traits
title_full Acetylene Derivatives of Cationic Diazaoxatriangulenes and Diaza [4]Helicenes ‐ Access to Red Emitters and Planar Chiral Stereochemical Traits
title_fullStr Acetylene Derivatives of Cationic Diazaoxatriangulenes and Diaza [4]Helicenes ‐ Access to Red Emitters and Planar Chiral Stereochemical Traits
title_full_unstemmed Acetylene Derivatives of Cationic Diazaoxatriangulenes and Diaza [4]Helicenes ‐ Access to Red Emitters and Planar Chiral Stereochemical Traits
title_short Acetylene Derivatives of Cationic Diazaoxatriangulenes and Diaza [4]Helicenes ‐ Access to Red Emitters and Planar Chiral Stereochemical Traits
title_sort acetylene derivatives of cationic diazaoxatriangulenes and diaza [4]helicenes ‐ access to red emitters and planar chiral stereochemical traits
topic Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9305763/
https://www.ncbi.nlm.nih.gov/pubmed/35040214
http://dx.doi.org/10.1002/chem.202104405
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