Dipartimento di Scienze e Tecnologie Chimiche, University of Rome-Tor Vergata, Italy.
Chemistry. 2012 Oct 29;18(44):14008-16. doi: 10.1002/chem.201202245. Epub 2012 Sep 27.
A "frozen" electron donor-acceptor array that bears porphyrin and fullerene units covalently linked through the ortho position of a phenyl ring and the nitrogen of a pyrrolidine ring, respectively, is reported. Electrochemical and photophysical features suggest that the chosen linkage supports both through-space and through-bond interactions. In particular, it has been found that the porphyrin singlet excited state decays within a few picoseconds by means of a photoinduced electron transfer to give the rapid formation of a long-lived charge-separated state. Density functional theory (DFT) calculations show HOMO and LUMO to be localized on the electron-donating porphyrin and the electron-accepting fullerene moiety, respectively, at this level of theory. More specifically, semiempirical molecular orbital (MO) configuration interaction (CI) and unrestricted natural orbital (UNO)-CI methods shed light on the nature of the charge-transfer states and emphasize the importance of the close proximity of donor and acceptor for effective electron transfer.
报道了一种“冻结”的电子给体-受体阵列，其中卟啉和富勒烯单元分别通过苯环的邻位和吡咯烷环的氮原子共价连接。电化学和光物理特性表明，所选择的连接体支持空间和键间相互作用。特别是，已经发现卟啉单重激发态在几皮秒内通过光诱导电子转移衰减，从而快速形成长寿命的电荷分离态。密度泛函理论（DFT）计算表明，在该理论水平上，HOMO 和 LUMO 分别定域在给电子卟啉和电子受富勒烯部分上。更具体地说，半经验分子轨道（MO）组态相互作用（CI）和非限制自然轨道（UNO）-CI 方法揭示了电荷转移态的性质，并强调了供体和受体的紧密接近对于有效电子转移的重要性。
