Scholarlink

<p>Two new post-synthetically functionalised (PSF) [2]rotaxanes (ROTb and ROTc) having tertiary amide groups are synthesised and characterised using 1D, various 2D-NMR, and variable temperature NMR spectroscopy. To synthesise <b>ROTb</b> and <b>ROTc</b>, an amino-ether macrocycle based [2]rotaxane (<b>ROT</b>) is used as a precursor. Attachment of tertiary amide functionalities via post synthetic functionalization of <b>ROT</b> results rotamer-induced dynamic nature in PSF [2]rotaxanes via the formation of various conformers/co-conformers. Additionally, comparative rotamer-induced kinetic properties of <b>ROTb</b> and <b>ROTc</b> along with a previously reported PSF interlocked molecule (<b>ROTa</b>) are demonstrated.<sup>1</sup> The NMR spectroscopic investigation shows that with systematic variation of the bulkiness of the substituents attached to tertiary amide groups appended in the post-synthetically functionalised rotaxanes (<b>ROTa</b>, <b>ROTb</b>, <b>ROTc</b>), the number of conformers/co-conformers are changing. The present comparative study establishes that, with small methyl group appended to amide in the PSF rotaxane (<b>ROTa</b>) shows existence of large number of conformers. Whereas, increasing the bulkiness from methyl group to tertiary butyl group in PSF rotaxane (<b>ROTc</b>), NMR studies show that <b>ROTc</b> does not show any readable kinetic nature which is due to the restricted tertiary amide bond rotation. However, the aryl group appended PSF rotaxane (<b>ROTb</b>) shows the existence of conformers in between <b>ROTa</b> and <b>ROTb</b> via <sup>1</sup>H-NMR studies.</p> Graphical abstract <p><b>ROTa</b> and <b>ROTb</b> show readable rotmer-induced dynamic nature, whereas, ROTc remains silent due to attachment of bulky tertiary butyl groupswith tertiary amides.</p> <p></p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Rotamer-induced dynamics in post-synthetically functionalized [2]rotaxanes: Effect of substituents appended to tertiary amide groups

  • 期刊论文

  • 发表日期：

    2026年3月7日

查看全文
  • Saikat Santra

摘要

Two new post-synthetically functionalised (PSF) [2]rotaxanes (ROTb and ROTc) having tertiary amide groups are synthesised and characterised using 1D, various 2D-NMR, and variable temperature NMR spectroscopy. To synthesise ROTb and ROTc, an amino-ether macrocycle based [2]rotaxane (ROT) is used as a precursor. Attachment of tertiary amide functionalities via post synthetic functionalization of ROT results rotamer-induced dynamic nature in PSF [2]rotaxanes via the formation of various conformers/co-conformers. Additionally, comparative rotamer-induced kinetic properties of ROTb and ROTc along with a previously reported PSF interlocked molecule (ROTa) are demonstrated.1 The NMR spectroscopic investigation shows that with systematic variation of the bulkiness of the substituents attached to tertiary amide groups appended in the post-synthetically functionalised rotaxanes (ROTa, ROTb, ROTc), the number of conformers/co-conformers are changing. The present comparative study establishes that, with small methyl group appended to amide in the PSF rotaxane (ROTa) shows existence of large number of conformers. Whereas, increasing the bulkiness from methyl group to tertiary butyl group in PSF rotaxane (ROTc), NMR studies show that ROTc does not show any readable kinetic nature which is due to the restricted tertiary amide bond rotation. However, the aryl group appended PSF rotaxane (ROTb) shows the existence of conformers in between ROTa and ROTb via 1H-NMR studies.

Graphical abstract

ROTa and ROTb show readable rotmer-induced dynamic nature, whereas, ROTc remains silent due to attachment of bulky tertiary butyl groupswith tertiary amides.