Synthesis and Characterization of Tetraphenylethene AIEgen-Based Push-Pull Chromophores for Photothermal Applications: Could the Cycloaddition-Retroelectrocyclization Click Reaction Make Any Molecule Photothermally Active?

Maxime Roger; Yann Bretonnière; Yann Trolez; Antoine Vacher; Imane Arbouch; Jérôme Cornil; Gautier Félix; Julien De Winter; Sébastien Richeter; Sébastien Clément; Philippe Gerbier

doi:10.3390/ijms24108715

Synthesis and Characterization of Tetraphenylethene AIEgen-Based Push-Pull Chromophores for Photothermal Applications: Could the Cycloaddition-Retroelectrocyclization Click Reaction Make Any Molecule Photothermally Active?

Int J Mol Sci. 2023 May 13;24(10):8715. doi: 10.3390/ijms24108715.

Affiliations

¹ ICGM, CNRS UMR 5253, ENSCM, University of Montpellier, 34293 Montpellier, France.
² ENS de Lyon, CNRS UMR 5182, Laboratoire de Chimie, University of Lyon, 69364 Lyon, France.
³ Ecole Nationale Supérieure de Chimie de Rennes, CNRS, ISCR-UMR 6226, University of Rennes, 35065 Rennes, France.
⁴ Laboratory for Chemistry of Novel Materials, University of Mons-UMONS, 7000 Mons, Belgium.
⁵ Organic Synthesis and Mass Spectrometry Laboratory (S2MOs), University of Mons-UMONS, 7000 Mons, Belgium.

Abstract

Three new tetraphenylethene (TPE) push-pull chromophores exhibiting strong intramolecular charge transfer (ICT) are described. They were obtained via [2 + 2] cycloaddition-retroelectrocyclization (CA-RE) click reactions on an electron-rich alkyne-tetrafunctionalized TPE (TPE-alkyne) using both 1,1,2,2-tetracyanoethene (TCNE), 7,7,8,8-tetracyanoquinodimethane (TCNQ) and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F₄-TCNQ) as electron-deficient alkenes. Only the starting TPE-alkyne displayed significant AIE behavior, whereas for TPE-TCNE, a faint effect was observed, and for TPE-TCNQ and TPE-F₄-TCNQ, no fluorescence was observed in any conditions. The main ICT bands that dominate the UV-Visible absorption spectra underwent a pronounced red-shift beyond the near-infrared (NIR) region for TPE-F₄-TCNQ. Based on TD-DFT calculations, it was shown that the ICT character shown by the compounds exclusively originated from the clicked moieties independently of the nature of the central molecular platform. Photothermal (PT) studies conducted on both TPE-TCNQ and TPE-F4-TCNQ in the solid state revealed excellent properties, especially for TPE-F4-TCNQ. These results indicated that CA-RE reaction of TCNQ or F₄-TCNQ with donor-substituted are promising candidates for PT applications.

Keywords: AIEgen; TPE; click chemistry; cycloaddition-retroelectrocyclization; photothermal applications.

MeSH terms

Alkynes*
Cycloaddition Reaction
Nitriles*

Substances

tetracyanoquinodimethane
Nitriles
Alkynes
tetracyanoethene

Grants and funding

This research was funded by the Ministère de l’Enseignement Supérieur, de la Recherche et de l’Innovation (MESRI) and by the Centre National de la Recherche Scientifique (CNRS).