Post-assembly processing of [2]rotaxanes

Sheng Hsien Chiu, Stuart J. Rowan, Stuart J. Cantrill, J. Fraser Stoddart*, Andrew J P White, David J. Williams

*この研究の対応する著者

研究成果: Article査読

60 被引用数 (Scopus)

抄録

The concept of using [2]rotaxanes that carry one or more surrogate stoppers which can subsequently be converted chemically into other structural units, resulting in the formation of new interlocked molecular compounds, is introduced and exemplified. Starting from simple NH2 +-centered/crownether-based [2]rotaxanes, containing either one or two benzylic triphenylphosphonium stoppers, the well-known Wittig reaction has been employed to make, 1) other [2]rotaxanes, 2) higher order rotaxanes, 3) branched rotaxanes, and 4) molecular shuttles - all isolated as pure compounds, following catalytic hydrogenations of their carbon-carbon double bonds, obtained when aromatic aldehydes react with the ylides produced when the benzylic triphenylphosphonium derivatives are treated with strong base. The two starting [2]rotaxanes were characterized fully in solution and also in the solid state by X-ray crystallography. The new interlocked molecular compounds that result from carrying out post-assembly Wittig reactions on two [2]rotaxanes were characterized by (dynamic) 1H NMR spectroscopy. In the case of a molecular shuttle in which the crown ether component is dibenzo[24]-crown-8 (DB24C8), shuttling is slow on the 1H NMR timescale, even at high temperatures. However, when DB24C8 is replaced by benzometaphenylene[25]-crown-8 as the ring component in the molecular shuttle, the frequency of the shuttling is observed to be around 100 Hz in [D4] methanol at 63 °C.

本文言語English
ページ(範囲)5170-5183
ページ数14
ジャーナルChemistry - A European Journal
8
22
DOI
出版ステータスPublished - 2002 11 15
外部発表はい

ASJC Scopus subject areas

  • 化学 (全般)

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