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

• Published in: Molecules (Basel, Switzerland) Switzerland), 2023-07, Vol.28 (15), p.5705
• Main Authors: Wang, Bin, Nan, Zi-Ang, Li, Qing, Liu, Jin, Lu, Zi-Xiu, Wang, Wei, Zhuo, Zhu, Li, Guo-Ling, Huang, You-Gui
• Format: Article
• Language: English
• Subjects: Communication; Crystallography; ester hydrate; Esters; Hydrogen; hydrogen bonding; Hydrogen bonds; intermediate; Ligands; Mass spectrometry; Porous materials; Radiation; Scientific imaging; self-assembly; π-stacking interaction
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules28155705

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 [CH OSO (OH) ] , serving as the template for the self-assembly of a π-stacked boat-shaped macrocycle (CH OSO (OH) ) (CH OSO ) @{[ClLCo ] }·Cl ·13CH OH·9H O ( ) (L = tris(2-benzimidazolylmethyl) amine), can be trapped in the host by multiple NH···O hydrogen bonds. In the solution of CoCl , L, and H SO in MeOH, HSO reacts with MeOH, producing [CH OSO ] via the ester hydrate intermediate of [CH OSO (OH) ] . 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.