Understanding adsorption processes of molecular species on silica surfaces is not only of basic interest, but it is also crucial for many synthetic procedures and purification processes. Typical fields involved are, for example, solid-phase synthesis, chromatography, ion exchange, or catalysis. In this contribution, we present surprising results on adsorbed phosphines, phosphine oxides, and phosphonium salts. Besides quantitative preparative chemistry, the nature and mobility of these adsorbed species are optimally investigated by multinuclear solid-state NMR. With classical 31P CP/MAS and 2H MAS, as well as HRMAS NMR, the changes in the CSA (Chemical Shift Anisotropy), the chemical shift, the quadrupolar coupling constant, and the residual halfwidth, on going from the molecular to the adsorbed species, are most indicative. Here, surprising new insights regarding the adsorption of respresentative phosphines, phosphine oxides, and phosphonium salts, and their diverse modes of mobility on the silica surface will be presented.

Adsorption of phosphines, phosphine oxides, and phosphonium salts on silica surfaces: New insights by solid-state NMR spectroscopy

243rd National Meeting (2012)

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