This work is focused on the design and synthesis of donor-acceptor pairs comprising of aza-BODIPY and tetraphenylethene (TPE) fluorogens with large pseudo Stokes shifts (386–424 nm). Femtosecond transient absorption spectroscopy, single crystal X-ray technique and TD-DFT studies were used to get more insight about their spectral behavior. As compared to the tetra-phenylaza-BODIPY, the four aza-BODIPYs exhibited 50–90 nm red shifted absoprtion and emission spectra. When the donor-acceptor architectures were excited at 300 nm, the aza-BODIPY unit emitted strong fluorescence in red region. This suggested an intramolecular energy transfer between donor (TPE) and the aza-BODIPY acceptor; with 81–90% energy transfer efficiencies. Femtosecond transient absorption studies also supported energy transfer process in the molecules, with 3.7 ps time constant associated with it. Aggregation studies in THF/n-heptane solution showed hypsochromic shifts in the aggregated form; X-ray packing structures indicated H-type aggregates (slip angle > 54.7°) in the solid state. Scanning electron microscopy (SEM) measurement revealed 200–700 nm size sphere shaped structures in the aggregated forms.

这项工作的重点是设计和合成由aza-BODIPY和具有大拟斯托克斯位移（386-424 nm）的四苯基乙烯（TPE）氟原子组成的供体-受体对。飞秒瞬态吸收光谱法，单晶X射线技术和TD-DFT研究用于获得有关其光谱行为的更多信息。与四苯基氮杂-BODIPY相比，四个氮杂-BODIPY表现出50-90 nm的红移吸收和发射光谱。当供体-受体结构在300 nm处激发时，aza-BODIPY单元在红色区域发出强荧光。这表明在供体（TPE）和氮杂-BODIPY受体之间进行了分子内能量转移。具有81–90％的能量传输效率。飞秒瞬态吸收研究还支持分子中的能量转移过程，具有3。与之相关的7 ps时间常数。在THF /正庚烷溶液中的聚集研究显示聚集形式的七色移；X射线堆积结构表明固态的H型聚集体（滑移角> 54.7°）。扫描电子显微镜（SEM）测量显示出聚集形式的200–700 nm大小的球形结构。