Anchoring of phosphonate and phosphinate coupling molecules on titania particles

Titanium oxide particles were treated using six organophosphorus compounds chosen as model coupling molecules: phenylphosphonic and diphenylphosphinic acids, their ethyl esters, and their trimethylsilyl esters. The ability of all of these coupling molecules to modify the surface of the TiO2 particle s was demonstrated by elemental analysis, thermogravimetric analysis, and n itrogen adsorption. The bonding modes on the surface were investigated by m eans of diffuse reflectance IR Fourier transform (DRIFT) and P-31 solid-sta te MAS NAM spectroscopy. Upon irradiation in water, a marked trend to the p hotooxidative degradation of the anchored organophosphorus groups was evide nced, especially in the case of phosphinate groups.