Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
Chem Asian J. 2018 May 18;13(10):1342-1347. doi: 10.1002/asia.201800264. Epub 2018 Apr 18.
The introduction of heavy atoms into conjugated molecules often induces a redshift in the emission spectra. Conversely, we report here a blueshifting effect in the absorption and emission bands of a conjugated organic dye by employing a heavier atom from the same element group. Boron complexes having oxygen- and sulfur-bridged structures in the ligand moiety were synthesized, and their optical properties were compared. Significant optical bands in the absorption and luminescence spectra of the sulfur-bridged complex were observed in a shorter wavelength region than those of the oxygen-bridged complex. Theoretical calculations suggest that replacement of the bridging atom by a heavier one should reduce molecular planarity because of the larger atom size. As a result, the degree of electronic conjugation decreases, and this is followed by a blueshift in the optical bands. Finally, a blue-emissive crystal is demonstrated.
引入重原子到共轭分子中通常会导致发射光谱红移。相反，我们在这里报道了通过使用同一元素组的较重原子，在共轭有机染料的吸收和发射带中产生蓝移效应。合成了具有配体部分中氧桥和硫桥结构的硼配合物，并比较了它们的光学性质。与氧桥配合物相比，硫桥配合物的吸收和荧光光谱中的显著光学带位于较短的波长区域。理论计算表明，由于原子尺寸较大，用较重的原子取代桥接原子应该会降低分子的平面性。因此，电子共轭度降低，这导致光学带蓝移。最后，展示了一种蓝色发射晶体。
