Formation of inclusion complexes between dimers of (R)-3-hydroxybutanoic acid and β-cyclodextrin: thermodynamic study of the complexation and conformational analysis of the complexed dimers
{"title":"Formation of inclusion complexes between dimers of (R)-3-hydroxybutanoic acid and β-cyclodextrin: thermodynamic study of the complexation and conformational analysis of the complexed dimers","authors":"Jun Li, K. Toh","doi":"10.1039/B104984B","DOIUrl":null,"url":null,"abstract":"The formation of inclusion complexes of di[(R)-3-hydroxybutanoate] (Dimer 1) and the methyl ester of di[(R)-3-hydroxybutanoate] (Dimer 2) with β-cyclodextrin (β-CD) was studied by NMR spectroscopy. The stoichiometry of the complexation was 1 ∶ 1 (host ∶ guest). Thermodynamic analysis revealed that the complex formation is enthalpically favorable, but entropically unfavorable. Dimer 1 forms hydrogen bonds with β-CD more frequently than Dimer 2 because 1 has two hydroxy groups. Conformational analysis of the 3HB (3-hydroxybutanoate) dimers in the complexes indicates that they have extended (trans) forms. In contrast, in solution without β-CD, the end of both Dimers 1 and 2 takes a sickle (gauche) shape due to formation of intermolecular hydrogen bonds.","PeriodicalId":17267,"journal":{"name":"Journal of The Chemical Society-perkin Transactions 1","volume":"20 1","pages":"35-40"},"PeriodicalIF":0.0000,"publicationDate":"2002-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"4","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of The Chemical Society-perkin Transactions 1","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1039/B104984B","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 4
Abstract
The formation of inclusion complexes of di[(R)-3-hydroxybutanoate] (Dimer 1) and the methyl ester of di[(R)-3-hydroxybutanoate] (Dimer 2) with β-cyclodextrin (β-CD) was studied by NMR spectroscopy. The stoichiometry of the complexation was 1 ∶ 1 (host ∶ guest). Thermodynamic analysis revealed that the complex formation is enthalpically favorable, but entropically unfavorable. Dimer 1 forms hydrogen bonds with β-CD more frequently than Dimer 2 because 1 has two hydroxy groups. Conformational analysis of the 3HB (3-hydroxybutanoate) dimers in the complexes indicates that they have extended (trans) forms. In contrast, in solution without β-CD, the end of both Dimers 1 and 2 takes a sickle (gauche) shape due to formation of intermolecular hydrogen bonds.