I want to study the host-guest activity based on perhydroxylated pillar[5]arene. According to previous literature, I dissolved DMpillar[5]arene to the anhydrous chloroform then added BBr3 to reduce the DMpillar[5]arene. After adding water into the mixture, it is hard to filtrate and get the white, viscous solid. Besides, when exposed in the air for a while, the white, viscous product would turn red, showing it was oxidized. How can I handle this situation?
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I did check the original procedure reported by Ogoshi et al. (JACS 2008) and it seems they are not paying any special attention to such an issues you are reporting. However the obtained yield of ~30% after demethylation suggests that a lot of some by-products will be present in the reaction mixture making purification not-so-trivial. The product - pillarene with free -OH groups will surely be prone to oxidation, but if it's properties towards air oxygene are similar to that of hydroquinone (and they should be) it would be OK, if you just work without any stress, but do the work-up and chromatography as fast as possible and than simply store your sample under nitrogen (or any other inert) atmosphere. If that does not help, still you can work under air-free conditions (e.g. Schlenk techniques) or ask Ogoshi et al. what is the trick (But in my personal opinion, the usual procedures will be enough - also be aware, that the red colour may mean only traces of the oxidized compound, at least in the beginng)
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