Ultrafast intramolecular charge transfer of formyl perylene observed using femtosecond transient absorption spectroscopy.
Ultrafast intramolecular charge transfer of formyl perylene observed using femtosecond transient absorption spectroscopy.
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DOI：
10.1021/jp107256f
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发表时间：
2010-11
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影响因子：
--
通讯作者：
O. Mohammed
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文献类型：
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作者：
O. Mohammed
研究了甲酰基苝（FPe）在一系列非极性、极性质子溶剂和极性非质子溶剂中的激发态电子物理。采用了各种实验和理论方法，包括飞秒瞬态吸收（fs-TA）光谱与130 fs的时间分辨率。我们报告说，超快的分子内电荷转移从二萘嵌苯单元甲酰基（CHO）基团可以大大促进之间的氢键相互作用的羰基氧的FPe和供氢溶剂在电子激发态。FPe在甲醇（MeOH）中的激发态吸收接近于由电子受体双分子淬灭产生的所报道的二萘嵌苯自由基阳离子。这是质子溶剂中S（1）态的大量电荷转移的强烈指示。质子溶剂中的偶极矩变化比非质子溶剂中的偶极矩变化增加得更大，这有力地支持了这一观察结果。弛豫机制，包括振动冷却和溶剂化耦合到电荷转移状态进行了讨论。
The excited-state photophysics of formylperylene (FPe) have been investigated in a series of nonpolar, polar aprotic, and polar protic solvents. A variety of experimental and theoretical methods were employed including femtosecond transient absorption (fs-TA) spectroscopy with 130 fs temporal resolution. We report that the ultrafast intramolecular charge transfer from the perylene unit to the formyl (CHO) group can be facilitated drastically by hydrogen-bonding interactions between the carbonyl group oxygen of FPe and hydrogen-donating solvents in the electronically excited state. The excited-state absorption of FPe in methanol (MeOH) is close to the reported perylene radical cation produced by bimolecular quenching by an electron acceptor. This is a strong indication for a substantial charge transfer in the S(1) state in protic solvents. The larger increase of the dipole moment change in the protic solvents than that in aprotic ones strongly supports this observation. Relaxation mechanisms including vibrational cooling and solvation coupled to the charge-transfer state are also discussed.