Rational Design of Push-Pull Fluorene Dyes: Synthesis and Structure-Photophysics Relationship.
Our work surveyed experimental and theoretical investigations to construct highly emissive D-π-A (D=donor, A=acceptor) fluorenes. The synthetic routes were optimised to be concise and gram-scalable. The molecular design was first rationalised by varying the electron-withdrawing group from an aldehyde, ketotriazole or succinyl to methylenemalonitrile or benzothiadiazole. The electron-donating group was next varied from aliphatic or aromatic amines to saturated cyclic amines ranging from aziridine to azepane. Spectroscopic studies correlated with TD-DFT calculations provided the optimised structures. The selected push-pull dyes exhibited visible absorptions, significant brightness, important solvatofluorochromism, mega-Stokes shifts (>250 nm) and dramatic shifts in emission to the near-infrared. The current library includes the comprehensive characterization of 16 prospective dyes for fluorescence applications. Among them, several fluorene derivatives bearing different conjugation anchors were tested for coupling and demonstrated to preserve the photophysical responses once further bound.
Institut de Chimie de Nice, UMR 7272, Université de Nice Sophia Antipolis, CNRS, Parc Valrose, 06108, Nice Cedex 2, France.
Janah
J
Shaya
Institut de Chimie de Nice, UMR 7272, Université de Nice Sophia Antipolis, CNRS, Parc Valrose, 06108, Nice Cedex 2, France.
Fabien
F
Fontaine-Vive
Institut de Chimie de Nice, UMR 7272, Université de Nice Sophia Antipolis, CNRS, Parc Valrose, 06108, Nice Cedex 2, France.
Benoît Y
http://orcid.org/0000-0002-8739-510X
BY
Michel
Institut de Chimie de Nice, UMR 7272, Université de Nice Sophia Antipolis, CNRS, Parc Valrose, 06108, Nice Cedex 2, France. burger@unice.fr.
Alain
http://orcid.org/0000-0001-5709-8086
A
Burger
Buchwald-Hartwig amination; charge transfer; fluorescent probes; push-pull fluorenes; structure-photophysics relationship