Fluorous interactions

Perfluoroaromatic rings are of special interest, because of CgFg—CeHsX stacking interactions and of their binding properties.  

This fluorous effect can also be effective for the stabilization of proteins. For example, the selective pairing of peptides that contain perfluorinated chains has been demonstrated, and perfluorinated amino acid side chains have been shown to stabilize the hydrophobic-driven folding of proteins.  

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This chapter aims to summarize our efforts to investigate the effects of fluorinated amino acid substitutes on the interactions with natural protein environments. In addition to a rather specific example concerning the interactions of small peptides with a proteolytic enzyme, we present a simple polypeptide model that aids for a systematic investigation of the interaction pattern of amino acids that differ in side chain length as well as fluorine content within both a hydrophobic and hydrophilic protein environment. Amino acid side chain fluoiination highly affects polypeptide folding due to steric effects, polarization, and fluorous interactions. 

Mamidyala SK, Ko KS, Jaipur FA, Park G, Pohl NL. Non-covalent fluorous interactions for the synthesis of carbohydrate microarrays. J. Flour. Chem. 2006 127 571-579. 

Figure 15.7 The rate of replication depends on the association-dissociation equilibrium. The data for time-dependent turnover raise the question whether fluorous interactions interfere with the association of the electrophilic fragment with the template thereby inhibiting catalysis [9]. See color plate 15.7.

In recent years, supported catalysts have become valuable tools for the simplified separation and recovery of catalysts from reaction mixtures. Commonly, the catalysts are attached covalently to a solid support. This covalent attachment of catalysts may lead to a partial loss of efficacy due to the decreased mobility. Alternatively, catalysts can be immobilized by non-covalent bonding through hydrogen bridges, or ionic, hydrophobic or fluorous interactions. Compared to covalent attachments, such non-covalent approaches increase the flexibility in the choice of the support material, reaction conditions and work-up strategies. 

Figure 8.1 Fluorous-based carbohydrate microarrays allow the patterning of fluorous-tagged carbohydrates based on noncovalent fluorous—fluorous interactions.

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