Near‐Infrared and Dual Emissions of Diphenylamino Group‐Substituted Malachite Green Derivatives

• Published in: European journal of organic chemistry Vol. 2022; no. 31
• Main Authors: Mori, Toshiaki, Sekine, Kohei, Kawashima, Kyohei, Mori, Toshifumi, Kuninobu, Yoichiro
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 19.08.2022
• Subjects: Carbocations; Cations; Dual emission; Emission; Fluorescence; Malachite green; Near infrared radiation; Near-infrared emission; Polystyrene resins; Solid-state emission; Substitutes; Toluene
• ISSN: 1434-193X; 1099-0690
• DOI: 10.1002/ejoc.202200873

Novel triarylmethanols and triarylmethyl cations with diphenylamino groups were designed and synthesized. The triarylmethyl cations exhibited near‐infrared (NIR) emission in toluene solution, solid film state, and polystyrene (PS) film. The emission intensities of the triarylmethyl cations were strongest in the PS film. The relative quantum yield of the PS film increased as the number of diphenylamino groups increased. In addition, triarylmethanols exhibit dual emission in their aggregated state owing to the intermolecular interactions between triphenyl amine moieties and/or hydroxy groups. These findings are interesting because NIR and dual emissions are not observed in the dimethylamino group‐substituted triarylmethyl cation, which is referred to as the “malachite green,” and the corresponding triarylmethanol, respectively. Triarylmethyl cations with diphenylamino groups exhibited near‐infrared (NIR) emission in toluene, solid film state, and polystyrene film. Diphenylamino group‐substituted triarylmethanols exhibited dual emission in their aggregated state. These results are in sharp contrast to those of dimethylamino group‐containing triarylmethanols and triarylmethyl cations.