Spectral Characteristics of Highly Fluorescent 2-(N,N-dimethylamino)tryptanthrin

Abstract

We previously reported that 2-aminotryptanthrin (T2NH₂) possesses excellent photophysical properties such as wide-wavelength absorption and emission in the visible region and a high fluorescence quantum yield. It also exhibits large positive fluorescent solvatochromism. In this study, we synthesized 2-(N,N-dimethylamino)tryptanthrin (T2NMe₂), from which we expected a substantial bathochromic shift of the emission band to the near-infrared (NIR) region by acceleration of intramolecular charge transfer. As such, the emission maxima (λ_{f, max}) of T2NMe₂ in some solvents were observed in the NIR region.