Meesala Yedukondalu, Kavala Veerababurao, Chang Hao-Ching, Kuo Ting-Shen, Yao Ching-Fa, Lee Way-Zen
Department of Chemistry, National Taiwan Normal University, Taipei, 11677, Taiwan (R.O.C.).
Dalton Trans. 2015 Jan 21;44(3):1120-9. doi: 10.1039/c4dt03052d.
A new series of four-ring-fused π-conjugated anilido-benzoxazole boron difluoride (ABB) dyes were synthesized by employing an unsymmetrical bidentate ligand under a mild reaction condition. X-ray structural analysis demonstrated that the four-ring-fused π-conjugated skeleton is nearly coplanar, and almost orthogonal to the side anilido phenyl group with dihedral angles of 74-86°. The synthesized complexes exhibit very bright luminescence in solution (Φf = 0.45-0.96 in CH2Cl2) and in the solid-state (Φf = 0.07-0.37). These complexes show a larger Stokes shift (56-128 nm) than the well-known boron dipyrromethene dyes (8-12 nm, in most cases). The role of molecular packing patterns elucidated by the assistance of their X-ray crystal structures rationalizes the solid-state fluorescence. One of the tested compounds displayed aggregation induced emission (AIE). First-principle-based quantum-chemical studies were carried out on complexes . Time-dependent DFT (TD-DFT) calculations support the experimental results. The participation of the anilido phenyl moiety and the fluorine atoms was found to be negligible in the LUMO orbitals.
通过在温和反应条件下使用不对称双齿配体，合成了一系列新型的四环稠合π共轭苯胺基苯并恶唑二氟化硼（ABB）染料。X射线结构分析表明，四环稠合π共轭骨架几乎共面，且与侧苯胺基苯基几乎正交，二面角为74-86°。合成的配合物在溶液（在二氯甲烷中Φf = 0.45-0.96）和固态（Φf = 0.07-0.37）中均表现出非常明亮的发光。这些配合物的斯托克斯位移（56-128 nm）比著名的二氟化硼二吡咯亚甲基染料（大多数情况下为8-12 nm）更大。借助其X射线晶体结构阐明的分子堆积模式的作用使固态荧光合理化。其中一种测试化合物表现出聚集诱导发光（AIE）。对配合物进行了基于第一性原理的量子化学研究。含时密度泛函理论（TD-DFT）计算支持实验结果。发现苯胺基苯基部分和氟原子在最低未占分子轨道（LUMO）中的参与可忽略不计。
