State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, and ‡Centre of Modern Analysis, Nanjing University , Nanjing 210093, China.
J Am Chem Soc. 2014 Oct 22;136(42):14666-9. doi: 10.1021/ja507918c. Epub 2014 Oct 14.
The one-electron oxidations of 1,8-chalcogen naphthalenes Nap(SPh)2 (1) and Nap(SPh)(SePh) (2) lead to the formation of persistent radical cations 1(•+) and 2(•+) in solution. EPR spectra, UV-vis absorptions, and DFT calculations show a three-electron σ-bond in both cations. The former cation remains stable in the solid state, while the latter dimerizes upon crystallization and returns to being radical cations upon dissolution. This work provides conclusive structural evidence of a sulfur-sulfur three-electron σ-bond (in 1(•+)) and a rare example of a persistent heteroatomic three-electron σ-bond (in 2(•+)).
1,8-杂萘硫醚 Nap(SPh)2 (1) 和 1,8-杂萘硒醚 Nap(SPh)(SePh) (2) 的单电子氧化导致在溶液中形成持久自由基阳离子 1(•+)和 2(•+)。EPR 光谱、紫外-可见吸收和 DFT 计算表明，两种阳离子中均存在三电子 σ 键。前者阳离子在固态中稳定存在，而后者在结晶时二聚化，并在溶解时恢复为自由基阳离子。这项工作提供了硫-硫三电子 σ 键（在 1(•+)中）的明确结构证据，以及罕见的持久杂原子三电子 σ 键（在 2(•+)中）的实例。
