ALUMINUM AND TITANIUM IMIDODIPHOSPHATES AS SINGLE PRECURSOR MOLECULES TO ALUMINUM AND TITANIUM PHOSPHATE MATERIALS

Abstract

The aluminum and titanium imidodiphosphates compounds respectively 1 and 2 are efficient single-source precursors to homogeneous aluminum and titanium phosphates materials. The conversion occurs pyrolytically at high temperature giving the corresponding compounds. Differential thermal and thermogravimetric analyses, ³¹P and ²⁷Al MAS NMR, as well as vibrational spectroscopies were used to characterize the final materials. In the case of the aluminum compound 1 it was found that the ²⁷Al MAS NMR signal representative of the octahedral aluminum observed in the material obtained at 900[ddot]C was transformed to a signal characteristic of a tetrahedrally aluminurn by increasing the temperature to 1200[ddot]C. This was confirmed by ³¹P MAS NMR and XPS studies. The thermal evolution of 2 was studied by using Raman spectroscopy. The conversion of the phosphate material to TiO₂ in the rutile phase after a thermal treatment at 1400[ddot]C during 3 hours was observed. The synthetic route to the phosphate materials described here could represent an alternative way to the sol-gel process and may offer certain advantages.

Key Words:

• Aluminum and Titanium imidodiphosphates
• High-temperature phase transformations
• ²⁷Al and ³¹P MAS NMR
• Raman
• XPS