Lu Yunxiang, Zou Jianwei, Wang Hongqing, Yu Qingsen, Zhang Huaxin, Jiang Yongjun
Department of Chemistry, Zhejiang University, Hangzhou, 310027, China.
J Phys Chem A. 2005 Dec 29;109(51):11956-61. doi: 10.1021/jp0547360.
Triangular halogen trimers (RX)3, where X = Br, I and R represents H, H3C, H2FC, HF2C, F3C, CH2=CH, CH[triple bond]C, and Ph, have been investigated using the density functional theory in the Perdew, Burke, and Ernzerhof method. We report herein the optimized geometries of the stable structures, their vibrational frequencies, and binding energies with the two- and three-body terms. All trimer structures possess a cyclic array of halogen atoms in the type II approach by virtue of the nonspherical atomic charge distribution around the halogens. The Br...Br interactions in trimers are very weak, whereas the I...I interactions in trimers are relatively stronger. While all bromine trimers and most of iodine trimers are predicted to be noncooperative, three of iodine trimers show weak cooperativity. The analysis of vibration modes reveals that all halogen trimers exhibit no especially remarkable frequency shifts. It is also shown that the electrostatic contribution plays a major role in the halogen...halogen interactions in halogen trimers. In contrast to bromine trimers, the relative contribution of charge-transfer component to the halogen...halogen interactions becomes more important for iodine trimers.
三角型卤素三聚体（RX）3，其中X = Br、I，R代表H、H3C、H2FC、HF2C、F3C、CH2=CH、CH≡C和Ph，已采用Perdew、Burke和Ernzerhof方法中的密度泛函理论进行了研究。我们在此报告稳定结构的优化几何结构、它们的振动频率以及二体和三体项的结合能。由于卤素周围的非球形原子电荷分布，所有三聚体结构在II型方法中都具有卤素原子的环状排列。三聚体中的Br...Br相互作用非常弱，而三聚体中的I...I相互作用相对较强。虽然所有溴三聚体和大多数碘三聚体预计是非协同的，但有三种碘三聚体表现出弱协同性。振动模式分析表明，所有卤素三聚体均未表现出特别显著的频率偏移。还表明，静电贡献在卤素三聚体的卤素...卤素相互作用中起主要作用。与溴三聚体相比，电荷转移成分对卤素...卤素相互作用的相对贡献对碘三聚体变得更为重要。
