Click chemistry is a method used in chemical synthesis and polymerization processes in which molecules are interlinked by reactive groups that will only connect with one another. Developed in the laboratory of K. B. Sharpless at The Scripps Research Institute in La Jolla, California, click reactions characteristically produce very high yields of a single product. Perhaps the best-known click reaction is the copper-catalyzed azide-alkyne cycloaddition to form triazines. See also: Click chemistry; Click chemistry in polymer science; Organic synthesis; Polymerization
In August 2014, the Sharpless group reported in the journal Angewandte Chemie International Edition a new click reaction called sulfur fluoride exchange (SuFEx). Among the SuFEx reactions reported:
• Sulfuryl fluoride (SO2F2) was found to exchange SF bonds for SO bonds with phenols to produce aryl fluorosulfates.
• Sulfonyl fluorides (RSO2F) were found to exchange SF bonds for SO bonds with aryl silyl ethers to produce diarylsulfates.
In addition, the reaction was used to produce the diarylsulfate polymer, bisphenol A polysulfate, which is similar in structure to polycarbonates made from bisphenol A. Polycarbonates are used in applications that require high impact resistance and optical transparency, such as automotive headlamp lenses, nonautomotive windscreens, and safety glasses; however, they are susceptible to hydrolysis (degradation by moisture) at conditions of high temperature and humidity. Early testing has indicated that bisphenol A polysulfate may have even greater impact resistance and may be more moisture stable than polycarbonates. See also: Humidity; Hydrolysis; Lens (optics); Optical materials; Organosilicon compound; Phenol; Polyester resins; Polymer
The SuFEx click reaction promises to provide an easier route to make known products as well as a method for making new molecules and polymers with yet-to-be-discovered properties for applications in chemistry, medicine, and materials science. See also: Organic chemistry; Materials science and engineering; Pharmaceutical chemistry