Institute of Experimental Physics, Free University Berlin , Arnimallee 14, 14195 Berlin, Germany.
Institute of Chemistry, The Hebrew University of Jerusalem , Jerusalem 91904, Israel.
Struct Dyn. 2016 May 12;3(4):043210. doi: 10.1063/1.4949363. eCollection 2016 Jul.
We combined femtosecond (fs) VIS pump-IR probe spectroscopy with fs VIS pump-supercontinuum probe spectroscopy to characterize the photoreaction of the hexacoordinated Al(tpfc-Br8)(py)2 in a comprehensive way. Upon fs excitation at ∼400 nm in the Soret band, the excitation energy relaxes with a time constant of (250 ± 80) fs to the S2 and S1 electronic excited states. This is evident from the rise time of the stimulated emission signal in the visible spectral range. On the same time scale, narrowing of broad infrared signals in the C=C stretching region around 1500 cm(-1) is observed. Energy redistribution processes are visible in the vibrational and electronic dynamics with time constants between ∼2 ps and ∼20 ps. Triplet formation is detected with a time constant of (95 ± 3) ps. This is tracked by the complete loss of stimulated emission. Electronic transition of the emerging triplet absorption band overlaps considerably with the singlet excited state absorption. In contrast, two well separated vibrational marker bands for triplet formation were identified at 1477 cm(-1) and at 1508 cm(-1). These marker bands allow a precise identification of triplet dynamics in corrole systems.
我们将飞秒（fs）可见（VIS）泵-红外（IR）探针光谱学与飞秒 VIS 泵-超连续谱探针光谱学相结合，全面表征了六配位 Al(tpfc-Br8)(py)2 的光反应。在 Soret 带的约 400nm 处进行飞秒激发时，激发能量以（250±80）fs 的时间常数弛豫到 S2 和 S1 电子激发态。这可以从可见光谱范围内受激发射信号的上升时间看出。在相同的时间尺度上，在 1500cm-1 左右的 C=C 伸缩区域观察到宽红外信号的变窄。在振动和电子动力学中，能量再分配过程的时间常数在 ∼2 ps 和 ∼20 ps 之间。用（95±3）ps 的时间常数检测到三重态的形成。这是通过完全失去受激发射来跟踪的。新出现的三重态吸收带的电子跃迁与单重激发态吸收重叠得相当厉害。相比之下，在 1477cm-1 和 1508cm-1 处鉴定出两个用于三重态形成的分离良好的振动标记带。这些标记带允许在 corrole 系统中精确识别三重态动力学。
