Molecules (Jul 2023)

Trapping an Ester Hydrate Intermediate in a π-Stacked Macrocycle with Multiple Hydrogen Bonds

  • Bin Wang,
  • Zi-Ang Nan,
  • Qing Li,
  • Jin Liu,
  • Zi-Xiu Lu,
  • Wei Wang,
  • Zhu Zhuo,
  • Guo-Ling Li,
  • You-Gui Huang

DOI
https://doi.org/10.3390/molecules28155705
Journal volume & issue
Vol. 28, no. 15
p. 5705

Abstract

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Ester hydrates, as the intermediates of the esterification between acid and alcohol, are very short-lived and challenging to be trapped. Therefore, the crystal structures of ester hydrates have rarely been characterized. Herein, we present that the mono-deprotonated ester hydrates [CH3OSO2(OH)2]−, serving as the template for the self-assembly of a π-stacked boat-shaped macrocycle (CH3OSO2(OH)2)0.67(CH3OSO3)1.33@{[ClLCoII]6}·Cl4·13CH3OH·9H2O (1) (L = tris(2-benzimidazolylmethyl) amine), can be trapped in the host by multiple NH···O hydrogen bonds. In the solution of CoCl2, L, and H2SO4 in MeOH, HSO4− reacts with MeOH, producing [CH3OSO3]− via the ester hydrate intermediate of [CH3OSO3(OH)2]−. Both the product and the intermediate serve as the template directing the self-assembly of the π-stacked macrocycle, in which the short-lived ester hydrate is firmly trapped and stabilized, as revealed by single-crystal analysis.

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