Guest-Host Inclusion Complex Formation of 2-, 3-, and 4-Aminobenzoic Acids with Native and Modified Cyclodextrins

Abstract

Abstract. The inclusion complexation of 2-aminobenzoic acid (2ABA), 3-aminobenzoic acid (3ABA), and 4-aminobenzoic acid (4ABA) with α-cyclodextrin (α-CD), β-cyclodextrin (β-CD), hydroxypropyl-α-cyclodextrin (HP-α-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD) were studied in buffer solutions of different pHs (pH~1 and pH~7) and it was carried out using UV-Visible, steady-state and time-resolved fluorescence. Dual fluorescence was observed for all the compounds in aqueous and CD medium. All the ABAs forms 1:1 inclusion complex at pH ~ 1 solution and mixture of 1:1 and 1:2 inclusion complex at pH ~7. With CDs, dual luminescence appeared at pH ~ 1 indicates, both NH3+ and COOH groups are present in the interior of the CDs cavities. FT-IR, 1H NMR, results suggest ABAs formed a stable inclusion complex with the CDs.

Complexation of Cyclodextrins with Benzoic Acid in Water-Organic Solvents: A Solvation-Thermodynamic Approach

“…The thermodynamic characteristics of the formation of complexes of inclusion of cyclodextrins with BA and its derivatives in water and the structure of the resulting complexes in the crystalline state are presented in numerous literature sources [ 10 , 11 , 12 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 ]. Most of them indicate the formation of complexes with a 1:1 stoichiometric ratio due to the predominance of van der Waals interactions and H-binding between guest molecules and CDs.…”