Department of Chemistry, KAIST, Daejeon 305-701, Republic of Korea.
Phys Chem Chem Phys. 2010 Jul 21;12(27):7648-53. doi: 10.1039/b923929d. Epub 2010 Jun 4.
Aromatic pi-pi interaction in the presence of a metal atom has been investigated experimentally and theoretically with the model system of bis(eta(6)-benzene)chromium-benzene cluster (Cr(Bz)(2)-Bz) in which a free solvating benzene is non-covalently attached to the benzene moiety of Cr(Bz)(2). One-photon mass-analyzed threshold ionization (MATI) spectroscopy and first principles calculations are employed to identify the structure of Cr(Bz)(2)-Bz which adopts the parallel-displaced configuration. The decrease in ionization potential for Cr(Bz)(2)-Bz compared with Cr(Bz)(2), resulting from the increase of the cation-pi stabilization energy upon ionization, is consistent with the parallel-displaced structure of the cluster. Theoretical calculations give the detailed cluster structures with associated energetics, thus revealing the nature of pi-pi-metal or pi-pi-cation interactions at the molecular level.
芳香族π-π 相互作用在金属原子存在的情况下已经通过模型体系二（η（6）-苯）铬-苯簇（Cr（Bz）（2）-Bz）进行了实验和理论研究，其中游离的溶剂苯以非共价键连接到 Cr（Bz）（2）的苯部分。单光子质量分析阈值电离（MATI）光谱和第一性原理计算用于确定 Cr（Bz）（2）-Bz 的结构，其采用平行位移构型。与 Cr（Bz）（2）相比，Cr（Bz）（2）-Bz 的电离势降低，这是由于在电离时阳离子-π 稳定能增加，这与簇的平行位移结构一致。理论计算给出了详细的簇结构及其相关的能量学，从而揭示了分子水平上π-π-金属或π-π-阳离子相互作用的性质。
