Inclusion complexation of novel synthesis amino acid based ionic liquids with β-cyclodextrin

• Published in: Journal of molecular liquids 2020-02, Vol.299, p.112204, Article 112204
• Main Authors: Banjare, Manoj Kumar, Banjare, Ramesh Kumar, Behera, Kamalakanta, Pandey, Siddharth, Mundeja, Prashant, Ghosh, Kallol K.
• Format: Article
• Language: English
• Subjects: Cyclodextrin; FTIR and NMR; Inclusion complex; Ionic liquids
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2019.112204

Inclusion complex formation between amino acid based ionic liquids (AAILs) i.e., 1-(2-(octylamino)-2-oxoethyl)pyridin-1-ium bromide and 4-((hydroxyimino)methyl)-1-(2-(octylamino)-2-oxoethyl)pyridin-1-ium bromide into β-cyclodextrin have been investigated in solution. The inclusion complexes (ICs) of AAILs with β-CD were synthesized through the co-precipitation method. The solid IC formation is characterized by numerous analytical techniques, primarily by UV–vis spectroscopy and secondary by major techniques i.e., FT-IR and 1H NMR. The binding constant and 1:1 stoichiometric of ICs nature of the complex between AAILs and β-CD in solution were determined by Job's plot method using UV–vis spectroscopy. As results suggest, the binding constants of ICs are higher for OAOEPB-β-CD as compared to HIMOAOEPB-β-CD. The different thermodynamic parameters such as change in standard Gibbs free energy (ΔG0), standard enthalpy changes (ΔH0) and standard entropy change (ΔS0) have been estimated with the help of van't Hoff equation. Noteworthy changes of IR stretching frequency also support the IC formation. 1H NMR results suggest that the tail part of AAILs is more suitably included inside the hydrophobic cavity of β-CD and it shows 1:1 stoichiometric ICs formation. Inclusion complexation (IC) between amino acid based ionic liquids i.e., 1-(2-(octylamino)-2-oxoethyl)pyridin-1-ium bromide and 4-((hydroxyimino)methyl)-1-(2-(octylamino)-2-oxoethyl)pyridin-1-ium bromide with β-cyclodextrin have been investigated by UV–Vis, FT-IR and 1H NMR spectroscopy. 1:1 stoichiometry of IC has been observed using Job plot method and confirmed by FT-IR and 1H NMR. [Display omitted] •The binding constants of β-CD are higher for OAOEPB as compared to HIMOAOEPB.•IR data give information about the functional groups concerned the stoichiometry ICs.•AAILs was clever to form ICs with β-CD in the 1:1 stoichiometric ICs by Job's plots.•UV–Vis spectroscopy, FT-IR and 1H NMR were carried out to confirm ICs formation.