Original synthesis and spectroscopic study of thiophene triazine derivatives with enhanced luminescence properties

Alysson Duarte Rodrigues; Nathalie Marcotte; Françoise Quignard; Stefano Deabate; Mike Robitzer; Dan A Lerner

doi:10.1016/j.saa.2019.117708

Original synthesis and spectroscopic study of thiophene triazine derivatives with enhanced luminescence properties

Spectrochim Acta A Mol Biomol Spectrosc. 2020 Feb 15:227:117708. doi: 10.1016/j.saa.2019.117708. Epub 2019 Oct 28.

Authors

Alysson Duarte Rodrigues¹, Nathalie Marcotte¹, Françoise Quignard², Stefano Deabate³, Mike Robitzer⁴, Dan A Lerner⁵

Affiliations

¹ ICGM, Univ Montpellier, ENSCM, CNRS, Montpellier, France; Ecole National Supérieure de Chimie de Montpellier, 240 Avenue du Professeur E. Jeanbrau, 34296, Montpellier Cedex 5, France.
² ICGM, Univ Montpellier, ENSCM, CNRS, Montpellier, France.
³ Institut Européen des Membranes, IEM - UMR, 5635, ENSCM, CNRS, Univ Montpellier, Montpellier, France; Ecole National Supérieure de Chimie de Montpellier, 240 Avenue du Professeur E. Jeanbrau, 34296, Montpellier Cedex 5, France.
⁴ ICGM, Univ Montpellier, ENSCM, CNRS, Montpellier, France; Ecole National Supérieure de Chimie de Montpellier, 240 Avenue du Professeur E. Jeanbrau, 34296, Montpellier Cedex 5, France. Electronic address: mike.robitzer@enscm.fr.
⁵ ICGM, Univ Montpellier, ENSCM, CNRS, Montpellier, France; Ecole National Supérieure de Chimie de Montpellier, 240 Avenue du Professeur E. Jeanbrau, 34296, Montpellier Cedex 5, France. Electronic address: dan.lerner@enscm.fr.

PMID: 31703995
DOI: 10.1016/j.saa.2019.117708

Abstract

A straightforward access to π-conjugated oligothiophenes bearing amino-rich groups was developed. Palladium-catalyzed C-H arylation applied in the main step of the synthesis allowed to couple 2-thiophenecarbonitriles and aryl bromides with moderate to excellent yields (35-93%). Then, to improve their basic fluorescence properties, these compounds were transformed into their 2,4-diamino-1,3,5-triazine derivatives, also with good to excellent yields (74-98%). UV-Visible absorption and fluorescence studies identified a strongly emissive molecule (fluorescence quantum yield: Φ_F = 0.78 ± 0.05), which could find use in sensors for applications in biology and in material chemistry. We observed an antagonistic effect in the spectroscopic properties of oligothiophenes bearing 2,4-diamino-1,3,5-triazine, resulting in improved absorptive and emissive properties for more constrained structures having shorter oligothiophenes chains.

Keywords: Fluorescence; Fluorescent label; Oligothiophene; Palladium catalyzed C–H arylation; Thiophene; Triazine.