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The mono-modified β-cyclodextrin derivative,6-O-(4-aminobenzoyl)-β-cyclodextrin(1) ,was synthesized and characterized. We compared its self-assembling behavior with structurally related β-cyclodextrin derivative,6-O-(4-hydroxybenzoyl)-βcyclodextrin(2) ,in aqueous solution and in the solid state using NMR spectroscopy and single crystal X-ray structure analysis. The two complexes displayed different self-assembling behaviors.Complex 1 formed a head-to-tail helical columnar superstructure in which the substituent group penetrated deeply into the hydrophobic cavity of the adjacent β-cyclodextrin from the second side and aligned along the screw axis,whereas 2 exhibited a channel superstructure with a tail-to-tail dimer as the repeating motif.Further NMR studies in aqueous solution supported the result of the solid state.The influence of substituent groups on the self-assembly behavior was examined in mono-modified β-cyclodextrins by means of substituting an amino group for a hydroxyl group,which indicates that the weak intermolecular interaction is a critical factor in determining the self-assembling behavior.
The mono-modified β-cyclodextrin derivative, 6-O- (4-aminobenzoyl) -β-cyclodextrin (1), was synthesized and characterized. We compared its self-assembling behavior with structurally related β-cyclodextrin derivative, (4-hydroxybenzoyl) -βcyclodextrin (2) in aqueous solution and in the solid state using NMR spectroscopy and single crystal X-ray structure analysis. The two complexes displayed different self-assembling behaviors. Complex 1 formed a head-to-tail helical columnar superstructure in which the substituent group penetrated deeply into the hydrophobic cavity of the adjacent β-cyclodextrin from the second side and aligned along the screw axis, and 2 exhibited a channel superstructure with a tail-to-tail dimer as the repeating motif. Further NMR studies in aqueous solution supported the result of the solid state. The influence of substituent groups on the self-assembly behavior was examined in mono-modified β-cyclodextrins by means of substituting an amino group for a hydroxyl group, which indicates that the weak intermolecular interaction is a critical factor in determining the self-assembling behavior.