Anchoring of Phosphonate and Phosphinate Coupling Molecules on Titania Particles

Abstract

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 particles was demonstrated by elemental analysis, thermogravimetric analysis, and nitrogen adsorption. The bonding modes on the surface were investigated by means of diffuse reflectance IR Fourier transform (DRIFT) and 31P solid-state MAS NMR spectroscopy. Upon irradiation in water, a marked trend to the photooxidative degradation of the anchored organophosphorus groups was evidenced, especially in the case of phosphinate groups.

Sticking and patching: tuning and anchoring cyclometallated ruthenium(ii) complexes

“…Hydrolytic deprotection of the ruthenium-bound diethyl phosphonates does not always proceed to completion 17,18,19,20,21 and phosphonate esters have been successfully used to modify TiO 2 surfaces, negating the need for this step. 22,23 …”

To deprotect or not to deprotect: Phosphonate ester versus phosphonic acid anchor ligands in copper(I)-based dye-sensitized solar cells

“…In the light of these observations, together with the empirically observed better solubility of the phosphonate esters compared to the phosphonic acids, we decided to investigate the use of phosphonate ester 2 (Scheme 1) as an anchoring ligand. It is already established that phosphonate esters may be used to modify TiO 2 surfaces under moderate conditions [20,21] with surface immobilization occurring by hydrolysis of POR groups by surface OH functionalities [22].…”

Interaction of sodium titanate nanotubes with organic acids and base: chemical, structural and morphological stabilities

“…The band at 1,516 cm -1 (1,416 cm -1 ) was observed in both spectra; it was attributed to asymmetric (symmetric) stretching modes of carboxylate groups, 35 indicating the presence of BA in these products. However, for the spectral region of the Ti-O vibrations (below 1,000 cm -1 ) we clearly observed a difference between the band features of these two products (curves c and d in Figure 1).…”

“…The stability of the P-O-M (M = metal) bond is illustrated by numerous examples reported in literature for metal phosphonates and metal phosphates. 35 In this paper, we have investigated the chemical, structural and morphological stabilities of the nanotubes in aqueous media containing organic acids (benzoic and phenylphosphonic acid) and an organic base (aniline). In addition, we also studied the products obtained through interaction between titanate nanotubes and organic molecules and evaluated the importance of some process parameters, such as contact time and temperature, on the nature of the final products.…”

“…Bands at 1,220 cm -1 (characteristic of P=O group) and 940 cm -1 (P-OH) were not observed either. 35,38 The absence of the bands related to P=O and P-OH groups, along with the presence of the signal related to the PO 3 group, indicates the formation of phenylphosphonate as a result of the interaction process. Moreover, we did not observe in the spectrum (curve b, Figure 1) the typical bands of titanate nanotubes in the spectral region below 1,000 cm -1 .…”