Metal-Free Clicking

Click chemistry is a term that was originally devised by Nobel-Prize winning-chemist Barry Sharpless to characterize reactions that you could pull off easily and efficiently – like clicking together children's play blocks. The example that he showed originally was that of a copper-catalyzed reaction between an alkyne and an azide, Source

although people are beginning to discover other reactions that fit the name such as the thiol-ene reaction. Given the need for polymerization reactions to occur over-and-over again-and-again repeatedly-and repeatedly, click reactions should have home in polymer chemistry and vice versa [*].

The alkyne-azide reaction indicated above has never been effectively used for polymerizations in part because the large amount of copper left over in the polymer can degrade the performance of the final polymer. The prepared polymers obviously have large amounts of unsaturated bonds that can be great enhancements to the electronic properties, but the residual metals can interfere with this. Fortunately, a group of researchers from China has announced that they have identified a metal-free polymerization scheme (open access). The reaction did require nitrogen blanketing for the polymerization, thus maybe making it less of a click reaction than normal, but that is still not overly oppressive requirement.

This was my first exposure to this journal, Science China Chemistry - I don't think it will be my last. In short, I like it. The formatting is high quality, and the research topics seem pretty top-notch too.

[*] Thiol-ene reactions are another example that people are beginning to recognize as having "clickability". And they are great for polymerizations – I've presented papers at the last two Society of Plastics Engineers conferences on their use, and there is pretty much an article a month in any of the major polymer journals.