The ability of the doublet excited state of perylene diimide anion radical 2(PDI-)* to reduce aromatic electron acceptors was probed by picosecond time resolved transient absorption (TA) spectroscopy. Excitation of PDI- produces visible TA due to 2(PDI-)* that decays with τ = 160 ps. Aromatic electron acceptors with varying reduction potential quench 2(PDI-)*, and in some cases give a new visible region absorption that is attributed to the products of bimolecular photoinduced electron transfer, 2(PDI-)* + Ar-X -> PDI + Ar-X-. Stern-Volmer quenching of 2(PDI-)* accomplished with a series of acceptors provide bimolecular quenching rate constants as a function of acceptor reduction potential. Rehm-Weller analysis of the electron transfer quenching data affords the potential for the (*PDI-/PDI) electrochemical half-reaction as -1.87 V vs SCE.

中文翻译：

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通过光激发苝二亚胺自由基阴离子直接观察芳基卤化物的还原

通过皮秒时间分辨瞬态吸收 (TA) 光谱探测苝二酰亚胺阴离子自由基 2(PDI-)* 的双激发态减少芳香族电子受体的能力。由于 τ = 160 ps 衰减的 2(PDI-)*，PDI- 的激发产生可见的 TA。具有不同还原电位的芳香族电子受体淬灭 2(PDI-)*，在某些情况下会产生新的可见区吸收，这归因于双分子光致电子转移的产物，2(PDI-)* + Ar-X -> PDI + Ar-X-。用一系列受体完成的 2(PDI-)* 的 Stern-Volmer 猝灭提供了作为受体还原电位函数的双分子猝灭速率常数。电子转移猝灭数据的 Rehm-Weller 分析提供了 (*PDI-/PDI) 电化学半反应的潜力，为 -1.87 V vs SCE。