Intercalation of primary monoamines in the lamellar protonic oxide HNb3O8 · H2O

The intercalation of alkyl monoamines in the protonic oxide HNb3O8 · H2O is quantitative for the amines NH2CnH2n+1 with n ranging from 1 to 9. The intercalated oxide NH3CH3Nb3O8 is anhydrous at room temperature whereas monohydrates NH3CnH2n+1NbO3 · H8O2 are the stable form at room temperature; these latter oxides can be dehydrated into the oxides NH3CnH2n+1Nb3O8 without any destruction of the structure, their zeolithic character is observed. The structural evolution of these compounds is interpreted in terms of a transversal orientation of the amine chains with respect to the [Nb3O8]− layers and compared to the one of the N3HCnH2n+1TiNbO5 oxides.