Inorganic-organic derivatives of layered perovskite-like titanates HLnTiO4 (Ln = La, Nd) with n-amines and n-alcohols: Synthesis, thermal, vacuum and hydrolytic stability

Protonated Ruddlesden-Popper phases HLnTiO(4) (Ln = La, Nd) have been used to yield two series of inorganic-organic derivatives containing non-covalently intercalated n-alkylamines and covalently grafted n-alkoxy groups with a various hydrocarbon chain length. Synthesis was carried out according to multistage schemes using both conventional benchtop and solvothermal methods. It was shown that inorganic-organic derivatives obtained contain approximately 0.4-0.5 interlayer organic molecules or groups per proton of the initial titanate as well as some amount of intercalated water. The introduction of organic components into the interlayer space of the titanates leads to its significant expansion and formation of a paraffin-like bilayer possessing an average tilting angle of 75.5 degrees. At the same time, the organic modification does not result in noticeable changes in light absorption of the samples in near-ultraviolet and visible regions. Their thermal stability strongly depends on the nature of the organic component bonding. While non-covalent amine derivatives are stable only at low temperatures <50 degrees C, covalent alkoxy ones can withstand heating up to 250 degrees C without perceptible decomposition. While most of the products demonstrate good stability under reduced pressure, some of them undergo phase composition changes upon prolonged exposure to water.

Automated summary

Protonated Ruddlesden-Popper phases HLnTiO(4) (Ln = La, Nd) have been used to synthesize inorganic-organic derivatives with intercalated n-alkylamines and covalently grafted n-alkoxy groups. The presence of organic components expands the interlayer space of the titanates, forming a paraffin-like bilayer structure with a large tilting angle. The organic modification does not affect the light absorption of the samples in the near-ultraviolet and visible regions. The thermal stability of the derivatives depends on the bonding nature of the organic components, with covalent alkoxy derivatives exhibiting better stability.