I used Click chemistry for the junction of polymer containing a terminal acetylene with inorganic-N3 material. In HNMR spectrum, the peaks of the polymer and inorganic material is seen, but the polymer has 140H so I cannot see the H in triazole ring. In the FT-IR spectrum of the click product, the acetylene's peak at 2119 is omitted which shows the success of the reaction. But how can I be sure about the successful junction of these compounds? Which method do you suggest?
You just need to compare FTIR before and after click-chimestry. I do the same reaction and I can see the difference since the pic 2200 disappear! You can also try 2D NMR (HMBC, HSQC N-H) you will see the coupling of your nitrogen with the H of the formed triazole. Good luck
You can go for X-ray diffraction that can give you the exact picture of the product formation.
Also, if the polymer you have used does not contains large number of nitrogen, then you can go for 15N NMR which will also help. Presence of large number of nitrogen in the polymeric unit will unnecessarily complicate the 15N NMR.
thanks all. The 15N NMR instrument is not available for me. Unfortunately the inorganic part has Si scaffold thus its purification is not easy. I have to investigate different solvents and conditions to remove unreacted Si from the polymer mixture.
But 13C NMR will give a complicate spectrum as you have mentioned about the presence of the polymeric unit in the acetylene moety. Hence, I think 13C NMR wil not be a very helpful tool. But as I said earlier XRD will be the most benificial technique in this case.
There is a coumarin azido derivative, 3-azido-7-diethylaminocoumarin, which is non-fluorescent. After a click-coupling the conjugate becomes blue-fluorescent. Schiedel, M.-S., C. A. Briehn, et al. (2001). "Single-Compound Libraries of Organic Materials: Parallel Synthesis and Screening of Fluorescent Dyes." Angewandte Chemie International Edition 40(24): 4677-4680
You just need to compare FTIR before and after click-chimestry. I do the same reaction and I can see the difference since the pic 2200 disappear! You can also try 2D NMR (HMBC, HSQC N-H) you will see the coupling of your nitrogen with the H of the formed triazole. Good luck
thanks Dear Dr. Popov. Reading your articles was useful for me.
Dear Dr. Ettaoussi: The FT-IR of the product before and after click reaction is satisfied but my main problem is by NMR spectrum. For publishing this work I need more analysis data and prove the click product completely by HNMR and CNMR.
Shima in your question you wrote
"But How can I be sure about the successful junction of these compounds? which method do you suggest?"
So, I am still suggesting CHN or related technique such as MALDI or ES-MS for starting and product. The difference will be the total N added. Since you will add 3N/unit and you already know the n unit number of your starting material then you have an answer of your Q. Of course, the disappearance of the sp carbons from C-13 NMR will help but this is not a sensitive tool in polymer(s). You can add the H-1 and C-13 spectral data in your publication.
Good luck
I have performed click reactions of this type on oligoethileneglycolmethacrylate based copolymers. I don't know the nature or the size of your polymers but there are several signals you could look at in the H-NMR. The triazol gives a singlet around 8-8.2 ppm. The proton of your terminal alkyne should be around 2 ppm before click and gone afterwards. Is there any CH2 group between your functional group and your azide? and between your polymer and the alkyne? Those signals should be easy to monitor as well before and after the reaction. Do you have your polymer fully characterized before the click? Then compare with the signals after.
Dear Elisa the proton of the terminal alkyne is overlapped by other signals and I couldn't see it. there are CH2 groups in my azide moiety and their signals are clear after Click. But my problem is: I couldn't see the triazol singlet around 8-8.2 ppm :-(
Dear Prabhu
My starting materials haven't any UV and the color of click product is the same. But I can check them again.
thanks
In a melting point test, at the time of melting, it is possible to observe a bubbling showing the release of N(gas[N2]).
Apart from the infrared, what you can do is to take your compound with triazoline to a photoreactor with the possible triazoline and letting it react releasing at the end nitrogen gas (N2) and it will be (at least in my case) a reaction with 100% yield without by-products, finally forming aziridine. Then you can take the triazoline and aziridine to a mass spectroscopy and see by the difference of the masses, which should be 28 g / mol.
Here you have a paper attached where you can read about FTIR, but i recommend the melting point test.
I have also done click chemistry in one of my paper. We got single crystal XRD as a solid proof(for organometallic complex). But in NMR you can see the downfield shift in the signal of triazole ring. Further absence of acetylene peak is enough to say that a triazole ring is formed.
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