Hello everyone!
Our group is trying to synthesize PIM-1 and bought some TFTPN from different companies. However, the TFTPN from different companies showed different colors-from white to yellow. The companies told us that they are the same good and provided us with the NMR spectrum. I am confused about how could the same compound has two colors. Did you encounter the same issue before or have any idea?
Thanks!
Dear Yuewen Jia, whatever the color is, it should be purified by sublimation prior to its use. My Regards
Dear Yuewen, many thanks for sharing this very interesting chemical question with the RG community. In this context, please have a look at the following useful Master thesis which is freely available as public full text on the internet:
Synthesis, Properties, and Solid-State Structures of a Series of 6,13-Dicyanoheteropentacene Analogues: Towards New Liquid Crystalline Materials
https://scholars.wlu.ca/cgi/viewcontent.cgi?article=3190&context=etd
(please see attached pdf file)
The synthesis of tetrafluoroterephthalonitrile (TFTPN) is described here on page 118. The compound was purified by recrystallization from acetone and isolated as a "straw yellow crystalline solid".
Good luck with your research work!
Hi Dr Yuewen Jia . See the link: https://pubs.rsc.org/en/content/articlehtml/2014/ra/c4ra03663h
Dear Dr Yuewen Jia,
I hope these articles (in attached) may help you in your research.
Best wishes,
Sabri
Dear Abdelkader BOUAZIZ
Thank you for your answer! I purified them by sublimation, but the colors are still different. So I am wondering why they still have different colors even though their existing forms are the same after sublimation. Do you have any idea?
Best regards,
Yuewen
Dear Yuewen Jia, this quotation is from the reference below: 'TFTPN was sublimated twice in vacuum prior to use', you can contact any of the authors for more details and clarification. My Regards
10.1039/C4RA03663H
Dear Yuewen Jia pure tetrafluoroterephthalonitrile should be present in the form of a colorless (white) crystalline solid. First of all you can employ double sublimation as mentioned by Abdelkader BOUAZIZ. When some yellow coloration still persists after the sublimations, you could check the purity in the TLC (e.g. using solvent like n-pentane of diethyl ether). In the case that the TLC reveals a yellow impurity spot, it might be worth a try to further purify the compound though column chromatography on silica gel. However, you should also consider if a minor impurity plays a significant role in further experiments with the tetrafluoroterephthalonitrile. Perhaps it can just be ignored. With best wishes, Frank Edelmann
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