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The deeper it goes, the brighter it glows: NIR emissive nitro-terrylene diimides with deep LUMOs

2023; Royal Society of Chemistry; Volume: 14; Issue: 12 Linguagem: Inglês

10.1039/d2sc06162g

2041-6539

Kundan Singh Mehra, Shivangee Jha, Anila M. Menon, Deepak Chopra, Jeyaraman Sankar,

Porphyrin and Phthalocyanine Chemistry

Herein, we present the first examples of air-stable, deep-lowest unoccupied molecular orbital (LUMO) polycyclic aromatic molecules with emission in the near-infrared (NIR) region, using nitration as a strategy. Despite the fact that nitroaromatics are non-emissive, the choice of a comparatively electron-rich terrylene core proved to be beneficial for achieving fluorescence in these molecules. The extent of nitration proportionately stabilized the LUMOs. Tetra-nitrated terrylene diimide exhibited a deep-LUMO (≤-4.5 eV) of -5.0 eV vs. Fc/Fc+, the lowest for any larger RDIs. These are also the only examples of emissive nitro-RDIs, with larger quantum yields.