Tris(perfluoroalkyl)silyl entities as unexpectedly potent tags for the noncovalent immobilization of catalysts by fluorous-fluorous interactions:: Application to the synthesis of several perfluoro-tagged ligands

Unexpectedly high retention times were obtained in HPLC investigations for compounds equipped with (C8F17CH2CH2)(3)Si tags on C8F17-modified silica gel (Fig. 4). Hence, these tags have a high potential for the noncovalent immobilization of catalysts to be applied in organic solvents, allowing for an easy separation and reuse of the catalyst by filtration and reapplication. The tris(perfluoroalkyl)silyl tag could be incorporated in a straightforward manner into ligands as demonstrated by the synthesis of several prominent classes of ligands (Schemes 4 - 6).