Benzylic cations with triplet ground states: Computational studies of aryl carbenium ions, silylenium ions, nitrenium ions, and oxenium ions substituted with meta π donors

被引：0
|
作者：
Winter, Arthur H. [1 ]
Falvey, Daniel E. [1 ]
Cramer, Christopher J. [2 ]
Gherman, Benjamin F. [3 ]
机构：
[1] Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742-2021, United States
[2] Department of Chemistry, Supercomputer Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, MN 55455-0431, United States
[3] Department of Chemistry, California State University, Sacramento, 6000 J Street, Sacramento, CA 95819-6057, United States
来源：
Journal of the American Chemical Society | 2007年 / 129卷 / 33期
关键词：
Density functional theory (B3LYP/6-31G(d,p)) was used to predict the effect of meta substitution on aryl cationic (Ar-X+) species, including aryloxenium ions, arylsilylenium ions, arylnitrenium ions, and arylcarbenium ions. Multireference second-order perturbation theory (CASPT2) calculations were used to benchmark the quantitative accuracy of the DFT calculations for representative systems. Substituting the meta positions on these species with π donors stabilizes a π,π* diradical state analogous to the wellknown m-xylylene diradical. Notably, the 3,5-bis(N,N-dimethylamino)benzyl cation is predicted to have a triplet ground state by 1.9 kcal/mol by DFT and to have essentially degenerate singlet-triplet states at the CASPT2(10,9) level of theory. Adding electron-withdrawing CF3 groups to the exocyclic carbon of this meta-disubstituted benzyl cation further increases the predicted singlet-triplet gap in favor of the triplet. Other aryl cationic species substituted with strong π electron-donating groups in the meta positions are predicted to have low-energy or ground-state triplet stales. Systems analogous to the naphthaquinodimethane diradicals are also reported. © 2007 American Chemical Society;
D O I：
暂无
中图分类号：
学科分类号：
摘要：
Journal article (JA)
引用
收藏
页码：10113 / 10119
相关论文
共 34 条
1234