5,10‐dihydro‐5,10‐dimethylphenazine (PZ) and boron dipyrromethene (Bodipy) were linked to prepare compact electron donor/acceptor dyads and triads. The effect of the molecular geometry on the UV‐Vis absorption, fluorescence and the spin‐orbit charge transfer intersystem crossing (SOCT‐ISC) efficiency were studied. Interestingly, a broad near‐IR charge transfer (CT) absorption band (centred at 670 nm) was observed for the dyad/triad showing more coplanar geometry. Triplet state formation was observed in low polar solvents for the triad with orthogonal geometry (triplet state quantum yield is 30 % and lifetime is τ_T=210 μs). Femtosecond transient absorption spectra indicated fast charge separation (CS, 2 ps) and slow charge recombination (CR, >1.5 ns). The low‐lying ³CT state of the dyads/triads in polar solvent (1.23 eV vs. the 1.65∼1.69 eV of the ³LE state) was confirmed by intermolecular triplet photosensitizing experiments and the spin density surface analysis. These results are useful for design of new broadband, near‐IR absorbing heavy atom‐free triplet photosensitizers.

中文翻译：

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吸收近红外的BODIPY-5,10-二氢吩嗪紧凑型电子供体/受体二重体和三重体：自旋轨道电荷转移系统间交叉和电荷转移状态

将5,10-dihydro-5,10-dimethylphenazine（PZ）和硼二吡咯亚甲基（Bodipy）连接起来以制备紧凑的电子供体/受体二元组和三元组。研究了分子几何形状对UV-Vis吸收，荧光和自旋轨道电荷转移系统间穿越（SOCT-ISC）效率的影响。有趣的是，对于二重体/三重体，观察到了较宽的近红外电荷转移（CT）吸收带（以670 nm为中心），显示出更多的共面几何形状。在低极性溶剂中，观察到与正交几何三元组三重态形成（三重态量子产率是30％，并且寿命是τ _Ť = 210微秒）。飞秒瞬态吸收光谱表明快速电荷分离（CS，2 ps）和缓慢电荷复合（CR，> 1.5 ns）。底层³通过分子间三重态光敏实验和自旋密度表面分析证实了极性溶剂中二元组/三元组的CT状态（1.23 eV对³ LE状态下的1.65〜1.69 eV ）。这些结果对于设计新型宽带，近红外吸收重无原子的三重态光敏剂很有用。