Department of Chemical Engineering, ‡Department of Chemistry, and §Center for Nanoscale Science and Engineering, University of California , Riverside, California 92521, United States.
J Am Chem Soc. 2016 Jan 13;138(1):40-3. doi: 10.1021/jacs.5b10598. Epub 2015 Dec 23.
Encapsulation of sulfur in HiPCO-SWNTs leads to large changes in the Raman spectra with the appearance of new peaks at 319, 395, and 715 cm(-1) which originate from the sulfur species within the SWNTs, while the high frequency SWNT bands (ν > 1200 cm(-1)) are decreased in intensity. The encapsulated species also shifts the near-IR interband electronic transitions to lower energy by more than 10%. These effects seem to originate with the van der Waals interaction of the confined sulfur species with the walls of the SWNTs which are not expected to be significant in the case of the previously studied large diameter SWNTs. We suggest that sulfur in the small diameter SWNTs exists as a helical polymeric sulfur chain that enters the SWNT interior in the form of S2 ((3)Σ(g)(-)) molecules which undergo polymerization to linear diradicals.
硫在 HiPCO-SWNTs 中的封装导致拉曼光谱发生了很大的变化，在 319、395 和 715 cm(-1) 处出现了新的峰，这些峰源于 SWNTs 内部的硫物种，而高频 SWNT 带（ν > 1200 cm(-1)）的强度降低。封装的物种也将近红外带间电子跃迁移至更低的能量，超过 10%。这些效应似乎源于被限制的硫物种与 SWNTs 壁之间的范德华相互作用，而在先前研究的大直径 SWNTs 中，这种相互作用预计不会很显著。我们认为，小直径 SWNTs 中的硫存在于螺旋状聚合物硫链中，以 S2((3)Σ(g)(-))分子的形式进入 SWNT 内部，然后进行聚合形成线性二自由基。
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