Hydrous protonated forms derived from n=3 Dion-Jacobson-type layered perovskite titanotantalate RbLa₂Ti₂TaO₁₀: Interlayer reactivity with n-alkylamine

Hydrous protonated forms of layered perovskite titanotantalate were derived from the n=3 Dion-Jacobson-type RbLa₂Ti₂TaO₁₀ by ion-exchange of the interlayer Rb⁺ ions in aqueous HNO₃, and their interlayer reactivity with n-alkylamine was investigated. Although all of the protonated forms thus derived were indexed as the same tetragonal cell with P4/mmm as the host, the interlayer reactivity with n-alkylamine was degraded with an increase in the ion-exchange treatment time. A significant difference was observed in dehydration behavior below 200 °C. The protonated forms synthesized with short ion-exchange time showed a large endothermic peak with weight loss around 60 °C, while those with prolonged treatment time did not. The intercalation of n-alkylamine was confirmed for the former, but not for the latter. From these results, it was considered that hydronium ions and/or H₂O molecules responsible for the dehydration around 60 °C play an important role in the intercalation of n-alkylamine into the protonated forms.