Aggregate, fluorous

Fluorous diphosphine complexes [Rh(COD)(12)]BF4 showed amphiphilic behavior, resulting in the formation of aggregates with a size of several hundreds... 

Fig. 17. Fluorous patches direct the pairing of protein segments in lipid micelles. The hydrophobic peptides partition into lipid micelles, forming a-helices. Then, the superhydrophobic hexafluoroleucine residues seek each other, causing self-association into dimers and higher order aggregates. Fluorine is light, while the backbone of the a-helices is dark. From Ref. [81], with permission.

In the early work by Davis and co-workers, it was shown that fluorous surfactants based on imidazolium cations could be developed to promote the formation and stabilization of perfluorocarbons in conventional ILs [40]. It was later demonstrated that ILs exhibit solvatophobic interactions with nonionic, anionic, and zwitterionic surfactant molecules prompting their aggregation within the solvent [26-28]. Interestingly, the CMC values for the... 

Owing to the high cost of fluorous chemicals efforts have been made to obtain C02-soluble hydrocarbon polymers and surfactants (68,69). With readily available hydrocarbon surfactants there is some indirect spectroscopic evidence for aggregation in CO2, but mostly in the presence of high levels of short-medium chain alcohols (60-62). The next section summarizes recent SANS... 

Homogeneous biocatalysis in both fluorous biphasic and supercritical CO systems has been demonstrated [6]. By forming protein-surfactant complexes by hydrophobic ion pairing with a highly fluorinated anionic surfactant cytochrome c can be solubilized in perfluoromethylcyclohexane (PMFC) and in scCO. The secondary structure of the proteins within these ion-paired complexes has been shown to remain intact, and particle size analysis indicated that small aggregates of protein molecules surrounded by surfactant molecules are formed. The presence of the KDP (perfluoropolyether carboxylate surfactants) ion paired with a-chymotrypsin appears to enhance its catal)4ic activity as compared to that of the native enzyme in a fluorous biphasic system. The facile recycling of the a-chymotrypsin-KDP complex in a fluorous biphasic system has been demonstrated with retention of enzyme artivity over four reaction cycles. 

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