1H-NMR study of the inclusion reactions of charged derivatives of α-cyclodextrin with sodium p-(3-t-butyl-4-hydroxyphenylazo)benzenesulfonate
Presence of an intermediate inclusion species is demonstrated by 270 MHz 1H-NMR spectroscopy in the system of the title azo compound and the charged derivatives of α-cyclodextrin. The 1H-NMR peaks due to the sulfanilate moiety of the guest molecule are distinctly split into two peaks upon binding to the positively charged cyclodextrin, suggesting the formation of an intermediate species.