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Updated: Feb 15, 2026

Negative Additive Manufacturing of Complex Shaped Boron Carbides
Published on: September 18, 2018
Switch-ON Near IR Fluorescent Dye Upon Protonation: Helically Twisted Bis(Boron Difluoride) Complex of π-Extended
Yutaka Hisamune1, Taeyeon Kim2, Keiichi Nishimura1
1Department of Chemistry and Biochemistry, Graduate School of Engineering, and Center for Molecular Systems, Kyushu University, Fukuoka, 819-0395, Japan.
Abstract:
A novel helically twisted π-extended corrorin derivative having two boron dipyrrin (BODIPY) moieties at the periphery, a BODIPY DYEmer (6-BF2 ) cross-bridged with π-conjugated dipyrrinylidene unit, was synthesized and characterized. The neutral 6-BF2 is nonfluorescent due to the internal photoinduced charge transfer (CT) character in the excited state as inferred from the femtosecond transient absorption spectroscopy. However, upon protonation, the CT process is suppressed and the species H6-BF2+ becomes near infrared (IR) emissive. With the aid of rigid helical conformations in 6-BF2 , the helical isomers (P- and M-forms) were resolved and their chiroptical property was investigated. The distinct circular dichroism (CD) spectral changes of the enantiomers were observed in the presence of acids, which demonstrates that 6-BF2 can be utilized for potential acid-responsive chiroptical materials.
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