Intercalation of 2-aminopropylamino-substituted β-cyclodextrin by α-and γ-zirconium phosphates

Abstract

The uptake of 6-(2-aminopropylamino)-6-deoxy-β-cyclodextrin (cdpn) by α-and γ-zirconium phosphates has been studied at 25 °C. The intercalation behaviour of the α-phosphate and the cdpn arrangement in the resulting intercalate are essentially the same as those observed previously with 6-(2-aminoethylamino)-6-deoxy-β-cyclodextrin (cden). On the other hand, the γ-phosphate forms a similar but slightly distorted bilayer of cdpn molecules with their cavity axes parallel to the phosphate layers. The interlayer spacing and the cdpn content in the intercalate vary abnormally with the amount of cdpn added. The cdpn or cden arrangement in α- or γ-zirconium phosphate is in marked contrast to that in copper-montmorillonite, which is explained in terms of the physicochemical characteristics of the individual inorganic interlayers and cyclodextrin molecules.