I know the Cuprous ion loses an electron during the CuAAC reaction. Resulting in formation of more stable in aqueous solutions cupric ion. I also observed that all triazoles obtained in homogeneous conditions are contaminated by copper, up to 168 ug/100mg of product. Cupric ion is most likely coordinated to the two nitrogen lone pairs on the triazole ring. If I was to avoid contamination. Should I chose a heterogeneous catalysis or is there a method that allows to remove the copper form from the already contaminated triazole product?
Once youve isolated your product, you can dissolve it in an organic solvent and try washing it with aqeuous EDTA
Hi Greg,
I actually have tried that but it seems that the affinity of cupric ion for the nitrogen lonepairs of the triazole product is greater than that for EDTA and so the purification is not as effective. There is still copper in the final product.
I used the salt as I didn't want to acidify the solution, which in my case is basic (pH 8.5). Managed to reduce the copper content by half. I also read a discussion here on research gate a while back in which a few methods were presented yet non was even 70% effective. Have you been working with triazoles yourself?
No I have not. Have you purified your triazole on silica gel? Also how do you know it is chelating copper? Mass spec?
I had three samples that were purified by column chromatography. To determine the copper content I used triazoles that were soluble in water (alcohol groups on the triazole ring). Had 100mg triazole/100ml 7% HNO3 sol. Copper content was checked with ICP-ES.
https://www.researchgate.net/post/how_to_remove_copper_after_CuAAc_click_reaction
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