Single Heteroatom Fine-Tuning of the Emissive Properties in Organoboron Complexes with 7‑(Azaheteroaryl)indole Systems

The application of organoboron compounds
as light-absorbing or
light-emitting species in areas as relevant as organic electronics
or biomedicine has motivated the search for new materials which contribute
to the progress of those applications. This article reports the synthesis
of four-coordinate boron complexes based on the unexplored 7-(azaheteroaryl)­indole
ligands. An easy synthetic approach has enabled the fine-tuning of
the electronic structure of the organoboron species by modifying a
heteroaromatic component in the conjugated system. Furthermore, a
comprehensive characterization by X-ray diffraction, absorption and
emission spectroscopy, both in solution and in the solid state, cyclic
voltammetry, and computational methods has evidenced the utility of
this simple strategy. Large Stokes shifts have been achieved in solid
thin-films which show a range of emitted light from blue to orange.
The synthesized compounds have been used as biocompatible fluorophores
in cell bioimaging.

有机硼化合物在有机电子学或生物医学等领域作为光吸收或光发射物种的应用，激发了寻找新型材料的探索，这些材料有助于推动相关应用领域的进步。本文报道了基于未充分探索的7-(氮杂杂环)吲哚配体的四配位硼络合物的合成。一种简便的合成方法使得通过调整共轭体系中的杂环组分，能够精细调节有机硼物种的电子结构。此外，通过X射线衍射、吸收和发射光谱（溶液态及固态）、循环伏安法和计算方法进行的全面表征，证实了该简单策略的实用性。在固体薄膜中实现了大的斯托克斯位移，这些薄膜能够发射从蓝色到橙色的光谱范围的光。合成的化合物已被用作细胞生物成像中的生物相容性荧光染料。