Department of Material and Life Science, Graduate School of Engineering, Osaka University, ALCA, Japan Science and Technology Agency (JST), Suita, Osaka, Japan.
J Phys Chem A. 2011 Dec 22;115(50):14430-7. doi: 10.1021/jp209668w. Epub 2011 Nov 23.
Photoinduced electron-transfer processes of a newly synthesized rodlike covalently linked ferrocene-naphthalenediimide-[60]fullerene (Fc-NDI-C(60)) triad in which Fc is an electron donor and NDI and C(60) are electron acceptors with similar first one-electron reduction potentials have been studied in benzonitrile. In the examined Fc-NDI-C(60) triad, NDI with high molar absorptivity is considered to be the chromophore unit for photoexcitation. Although the free-energy calculations verify that photoinduced charge-separation processes via singlet- and triplet-excited states of NDI are feasible, transient absorption spectra observed upon femtosecond laser excitation of NDI at 390 nm revealed fast and efficient electron transfer from Fc to the singlet-excited state of NDI ((1)NDI*) to produce Fc(+)-NDI(•-)-C(60). Interestingly, this initial charge-separated state is followed by a stepwise electron transfer yielding Fc(+)-NDI-C(60)(•-). As a result of this sequential electron-transfer process, the lifetime of the charge-separated state (τ(CS)) is elongated to 935 ps, while Fc(+)-NDI(•-) has a lifetime of only 11 ps.
在苯腈中研究了新合成的棒状共价连接的二茂铁-萘二酰亚胺-[60]富勒烯（Fc-NDI-C（60））三联体的光诱导电子转移过程，其中 Fc 是电子供体，NDI 和 C（60）是电子受体，具有相似的第一单电子还原电位。在研究的 Fc-NDI-C（60）三联体中，具有高摩尔吸光率的 NDI 被认为是光激发的发色团单元。尽管自由能计算验证了通过 NDI 的单重态和三重态激发进行光致电荷分离过程是可行的，但在 390nm 处用飞秒激光激发 NDI 时观察到的瞬态吸收光谱表明，电子从 Fc 快速有效地转移到 NDI 的单重激发态（（1）NDI*），以产生 Fc(+)-NDI(•-)-C(60)。有趣的是，初始电荷分离态随后是逐步电子转移，生成 Fc(+)-NDI-C(60)(•-)。由于这种顺序电子转移过程，电荷分离态（τ(CS)）的寿命延长至 935ps，而 Fc(+)-NDI(•-)的寿命仅为 11ps。
