Phosphorus immobilization

Caraco, N.F., Cole, J.J., and Likens, G.E. (1990) A comparison of phosphorus immobilization in sediments of freshwater and coastal marine systems. Biogeochemistry 9, 277-290. 

Many catalysts, both immobilized (on solid state supports) and heterogeneous, contain phosphines and other phosphorus compounds, so that solid state NMR has become an invaluable tool in the study of catalysis. 

Fig. 50 Phosphorus-31 CP/MAS spectrum of the nickel complex shown, which is immobilized on silica gel, recorded at a spinning rate of 4 kHz (lower spectrum) and HRMAS spectrum of an acetone suspension, recorded at a spinning rate of 2 kHz (upper spectrum)...

Transition-metal phosphorus trichalcogenides such as MnPS3 are able to intercalate amino acids and peptides by ion exchange. In this way, increases in the basal spacing of 0.7 and 3-4 nm are observed for the intercalation of poly-L-lysine and lysozyme, respectively [224]. Interestingly, the enzymatic activity of the immobilized protein has been detected, suggesting that the enzyme is protected against denaturation. 

There is one more report on the synthesis of a library of phosphorus ligands on solid phase. Waldmann et al. prepared a library of phosphoramidites on beads (Fig. 36.5), but these were only applied in enantioselective C-C-bond formation. In fact, as two ligands need to be bound to the catalyst, the use of an immobilized monodentate ligands should most likely be avoided unless the proximity between the ligands is sufficiently close. In addition, crosslinking by the metal may have a negative impact on the permeability of the polymer for the substrate. 

Figure 6 The immobilized phosphorus-ligated cobalt catalysts.

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