Surface characterization of systems with diphenylphosphinoethylsilane immobilized on silica gel

Abstract Diphenylphosphinoethyltriethoxysilane and alkylsilylating reagents have been reacted with silica gel to produce a surface with anchored ligands within a hydrophobic matrix. The extent of surface coverage has been determined using elemental analysis data. Cross-polarization/magic angle spinning, nuclear magnetic resonance has contributed toward a description of the diphenylphos-phinoethylsilyl anchored on the surface. Using high-performance liquid chromatography, the extent of substrate coverage and ligand stability were evaluated. The experimental data provide some insight into the synthetic procedure which is most effective for the preparation of stable diphenyl-phosphine moieties immobilized on silica gel. Since diphenylphosphinoethylsilyl is often used to immobilize metal complexes, the information should be useful for optimizing systems for use in heterogeneous catalysis.