Life Science Center of Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan.
J Am Chem Soc. 2012 Nov 28;134(47):19401-8. doi: 10.1021/ja307341g. Epub 2012 Nov 13.
An endohedral metallofullerene, La(2)@C(80), is covalently linked to the strong electron acceptor 11,11,12,12-tetracyano-9,10-anthra-p-quinodimethane (TCAQ) by means of the Prato reaction, affording two different [5,6]-metallofulleropyrrolidines, namely 1a and 2a. 1a and 2a were isolated and fully characterized by means of MALDI-TOF mass, UV-vis-NIR absorption, and NMR spectroscopies. In addition, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) corroborated the unique redox character of 2a, that is, the presence of the electron-donating La(2)@C(80) and the electron-accepting TCAQ. Although a weak electronic coupling dictates the interactions between La(2)@C(80) and TCAQ in the ground state, time-resolved transient absorption experiments reveal that in the excited state (i.e., π-π* centered at La(2)@C(80)) the unprecedented formation of the (La(2)@C(80))(•+)-(TCAQ)(•-) radical ion pair state evolves in nonpolar and polar media with a quantum efficiency of 33%.
一种笼型金属富勒烯 La(2)@C(80) 通过 Prato 反应与强电子受体 11,11,12,12-四氰基-9,10-蒽醌二亚甲基（TCAQ）共价键合，得到两种不同的[5,6]-金属富勒吡咯烷，即 1a 和 2a。1a 和 2a 通过 MALDI-TOF 质量、UV-vis-NIR 吸收和 NMR 光谱法进行分离和充分表征。此外，循环伏安法（CV）和差分脉冲伏安法（DPV）证实了 2a 的独特氧化还原特性，即存在供电子 La(2)@C(80)和电子受体 TCAQ。尽管弱电子耦合决定了基态下 La(2)@C(80)和 TCAQ 之间的相互作用，但时间分辨瞬态吸收实验表明，在激发态（即 La(2)@C(80)中心的π-π*）中，前所未有的（La(2)@C(80))(•+)-(TCAQ)(•-)自由基离子对态在非极性和极性介质中以 33%的量子效率演化。
