We report the results of photoinduced electron transfer (PET) in a novel dyad, in which a boron dipyrromethene (BODIPY) dye is covalently linked to o-carborane (o-Cb). In this dyad, BODIPY and o-Cb act as electron donor and acceptor, respectively. PET dynamics were investigated using a femtosecond time-resolved transient absorption spectroscopic method. The free energy dependence of PET in the S₁ and S₂ states was examined on the basis of Marcus theory. PET in the S₁ state occurs in the Marcus normal region. Rates are strongly influenced by the driving force (−ΔG), which is controlled by solvent polarity; thus, PET in the S₁ state is faster in polar solvents than in nonpolar ones. However, PET does not occur from the higher energy S₂ state despite large endothermic ΔG values, because deactivation via internal conversion is much faster than PET.

中文翻译：

---

时间分辨瞬态吸收光谱法研究BODIPY-邻-硼烷二元系中的光诱导电子转移

我们报告了在新型二元组中的光致电子转移（PET）的结果，其中硼二吡咯亚甲基（BODIPY）染料与o-碳硼烷（o- Cb）共价连接。在这个二元组中，BODIPY和o -Cb分别充当电子给体和受体。使用飞秒时间分辨瞬态吸收光谱法研究PET动力学。根据Marcus理论，研究了PET在S ₁和S ₂状态下的自由能依赖性。S ₁状态的PET发生在Marcus正常区域。率是由驱动力（-Δ强烈影响ģ），其通过溶剂极性控制; 因此，S _1中的PET极性溶剂比非极性溶剂状态更快。但是，尽管吸热ΔG值很大，PET也不会从较高的能量S ₂状态发生，因为通过内部转换的失活要比PET快得多。