Triarylmethane dye ethynologue with a fused julolidine motif as a compact dye in the near infrared range

Abstract

Near-infrared (NIR) dyes have garnered significant attention for applications in bioimaging and optoelectronics due to their low phototoxicity and excellent tissue penetration. However, many conventional NIR dyes rely on extended π-conjugated systems and require complex multi-step syntheses. In this study, we report the development of compact NIR-absorbing dyes based on triarylmethane dye ethynologues. A series of compounds was synthesized by incorporating a julolidine unit as a strong electron-donating group and modifying either electron-donating or electron-withdrawing substituents on the aromatic rings adjacent to the carbocation center. The julolidine moiety effectively red-shifted the absorption into the NIR region, while electron-donating groups enhanced photostability and resistance under acidic conditions. Nevertheless, the presence of alkyne linkages makes the dyes susceptible to degradation under basic conditions, as well as to oxidation and thermal decomposition, limiting their long-term durability. Ongoing efforts focus on overcoming these drawbacks to advance the practical applications of these dyes in photocatalysis, photonic devices, and solar energy conversion systems. This work offers a promising approach toward the sustainable design of compact, efficient, and synthetically accessible NIR dyes.

Graphical abstract: Triarylmethane dye ethynologue with a fused julolidine motif as a compact dye in the near infrared range

Supplementary files

Article information

Article type
Paper
Submitted
07 Apr 2025
Accepted
24 Jul 2025
First published
25 Jul 2025

New J. Chem., 2025, Advance Article

Triarylmethane dye ethynologue with a fused julolidine motif as a compact dye in the near infrared range

H. Kitaoka, K. Kobayashi, M. Yasui, T. Konno and S. Yamada, New J. Chem., 2025, Advance Article , DOI: 10.1039/D5NJ01519G

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements