How To Make Nitroaromatic Compounds Glow: Next‐Generation Large X‐Shaped, Centrosymmetric Diketopyrrolopyrroles

Language
en
Document Type
Article
Issue Date
2021-02-24
First published
2020-09-07
Issue Year
2020
Authors
Skonieczny, Kamil
Papadopoulos, Ilias
Thiel, Dominik
Gutkowski, Krzysztof
Haines, Philipp
McCosker, Patrick M.
Laurent, Adèle D.
Keller, Paul A.
Clark, Timothy
Jacquemin, Denis
Editor
Publisher
Wiley-VCH Verlag GmbH & Co. KGaA
Abstract

Abstract Red‐emissive π‐expanded diketopyrrolopyrroles (DPPs) with fluorescence reaching λ=750 nm can be easily synthesized by a three‐step strategy involving the preparation of diketopyrrolopyrrole followed by N‐arylation and subsequent intramolecular palladium‐catalyzed direct arylation. Comprehensive spectroscopic assays combined with first‐principles calculations corroborated that both N‐arylated and fused DPPs reach a locally excited (S1) state after excitation, followed by internal conversion to states with solvent and structural relaxation, before eventually undergoing intersystem crossing. Only the structurally relaxed state is fluorescent, with lifetimes in the range of several nanoseconds and tens of picoseconds in nonpolar and polar solvents, respectively. The lifetimes correlate with the fluorescence quantum yields, which range from 6 % to 88 % in nonpolar solvents and from 0.4 % and 3.2 % in polar solvents. A very inefficient (T1) population is responsible for fluorescence quantum yields as high as 88 % for the fully fused DPP in polar solvents.

Journal Title
Angewandte Chemie International Edition
Volume
59
Issue
37
Citation

Angewandte Chemie International Edition 59.37 (2020): S. 16104-16113. https://onlinelibrary.wiley.com/doi/10.1002/anie.202005244

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