Department of Chemistry and ‡Mork Family Department of Chemical Engineering and Materials Science, University of Southern California , Los Angeles, California 90089, United States.
J Org Chem. 2017 Jul 21;82(14):7215-7222. doi: 10.1021/acs.joc.7b00786. Epub 2017 Jul 11.
Boron dipyrromethene (BODIPY) derivatives have found widespread utility as chromophores in fluorescent applications, but little is known about the photophysical properties of pyridine-based BODIPY analogues, dipyridylmethene dyes. Indeed, it has been reported that boron difluoride dipyridylmethene (DIPYR) is nonemissive, and that derivatives of DIPYR have modest, if any, luminescence. In this report, we explore this little-touched area of chemical space and investigate the photophysical properties of three simple DIPYR dyes: boron dipyridylmethene, boron diquinolylmethene, and boron diisoquinolylmethene. The three dyes strongly absorb in the blue-green part of the spectrum (λ = 450-520 nm, ε = 2.9-11 × 10 M cm) and display green fluorescence with high quantum yields (Φ = 0.2, 0.8, and 0.8, respectively). Key photophysical properties in these systems were evaluated using a combination of TD-DFT and extended multiconfigurational quasidegenerate second-order perturbation theory (XMCQDPT2) methods and compared to experimental results, revealing that high quantum yields of the quinoline and isoquinoline derivatives are a result of the relative reordering of S and T state energies upon benzannulation of the parent structure. The intense absorption and high emission efficiency of the benzannulated derivatives make these compounds an intriguing class of dyes for further derivatization.
硼二吡咯甲川（BODIPY）衍生物作为荧光应用中的发色团得到了广泛的应用，但对于基于吡啶的 BODIPY 类似物、二吡啶甲川染料的光物理性质知之甚少。事实上，据报道，二氟化硼二吡啶甲川（DIPYR）是非发光的，并且 DIPYR 的衍生物如果有发光的话也是适度的。在本报告中，我们探索了这个化学空间中很少涉及的领域，并研究了三种简单的 DIPYR 染料的光物理性质：硼二吡咯甲川、硼二喹喔啉甲川和硼二异喹啉甲川。这三种染料在蓝绿色光谱部分强烈吸收（λ = 450-520nm，ε = 2.9-11×10 M cm），并显示出高量子产率的绿色荧光（Φ = 0.2、0.8 和 0.8，分别）。在这些体系中，使用 TD-DFT 和扩展多组态准简并二级微扰理论（XMCQDPT2）方法的组合评估了关键的光物理性质，并将其与实验结果进行了比较，结果表明，喹啉和异喹啉衍生物的高量子产率是母体结构苯并环化导致 S 和 T 态能量相对重排的结果。苯并环化衍生物的强烈吸收和高发射效率使这些化合物成为进一步衍生化的一类有趣的染料。
