Fluorous media for extraction and transport

Selective partitioning can be useful for sample cleanup or the isolation and purification of desired compounds. Fluorocarbon solvents and polymers, and solvents or polymers with similar properties that are not composed solely of carbon and fluorine (so-called ‘fluorous’ solvents or polymers) have a low ability to dissolve or sorb solutes or penetrants. This lack of solvating ability can lead to selective extractions. Fluorous phases will solvate, and therefore extract or transport, fluorous solutes, or non-fluorous solutes that are stabilized in the fluorous phase by non-covalent interactions with a ‘host’ or ‘receptor’ molecule that is in the fluorous phase. In this review, there is a brief discussion of molecular recognition as applied to selective extraction. Fluorous solvents are introduced, and there is a description of some recent applications, chiefly in synthetic organic chemistry. In particular, it is important to understand solute partitioning behavior and methods to predict it when one of the solvents is fluorous. Fluorous polymers Teflon AF1600 and AF2400 have been used in separations. Their rather complex and still not completely understood properties in separations and transport are described. There is a discussion of molecular recognition in fluorous phases as well as a brief discussion of efficient methods of carrying out extractions for analytical or physicochemical purposes.