Phosphonate‐Type Pseudo‐Grafted Precursor: Efficient Surface Modification of Silica

Abstract

AbstractSurface modification of inorganic metal oxides by grafting phosphonate compounds is a highly useful method for acquiring organic–inorganic hybrid materials. Compared to metal oxides, it is still difficult to modify silica by phosphonates. In this work, we developed an arylphosphonate “pseudo‐grafted precursor” (P‐PGP 1) bearing a disilicate moiety (−OSi(OtBu)2OSi(OtBu)2O−). While conventional grafting methods rely on Si−O−P bond formation, P‐PGP 1 undergoes Si−O−Si bond formation through a substitution reaction on the silicon atoms of the disilicate moiety. Therefore, P‐PGP 1 was grafted onto a silica surface at room temperature with a higher phosphorus content than that obtained with arylphosphonic acid. The characterization of surface species by 31P and 13C CP/MAS NMR analyses and the evaluation of the phosphorus content suggested that the grafting mode of P‐PGP 1 allows efficient surface modification of the silica surface.