Hi everyone. Recently I got the FTIR result for the synthesis of schiff base that I made that day. But in my FTIR data when I compare it with the IR spectrum table, the peaks for C = O and N-H of the starting material are still there. The starting material that i use for the synthesis of schiff base are phenylalanine and terephthaldehyde. The target product should be absence of N-H and presence of OH (from carboxylic acid) and presence of C=N (from reaction between amine group of phenylalanine and carbonyl group of terephthaldehyde). During the experiment i do really get the yellow precipitate which means that a reaction occurs between the starting materials that I use. I really hope you can help me to resolve this confusion of mine. Thank you in advance and have a nice day.
Hello Fatin,
Thanks for sharing your question with the RG community. Your schiff base is structurally close to your starting compounds. Due to the large number of bands in virtually all regions of the spectrum, it would be helpful if you could also share the measured IR spectra of your starting compounds or the wavenumbers of the most important bands. By the way, the structural formula of your target compound is missing a double bond at the second N atom.
Dear Fatin, thank you for posting this very interesting technical question on RG. Schiff base ligands like yours have been reported in the literature reference cited below. The article also contains FTIR data of the compounds:
Synthesis, Spectral and Antibacterial Activity of Mixed Ligand from Lanthanium (III) Complexes of Schiff Base Ligand with Some Amino Acids
Article Synthesis, Spectral and Antibacterial Activity of Mixed Liga...
Fortunately this article has been posted by the authors as public full text on RG. Thus you can freely download it as pdf file. The fact that you obtained a yellow precipitate clearly indicates the formation of the desired Schiff base. In order to remove unreacted starting materials you can try to recrystallize your product from boiling ethanol.
Good luck with your work!
Thank you Mr. Florian Morsbach for answering my question. I just noticed that my structural formula are missing a double bond at the second N atom. Thank you for informing me ^^
Dear Fatin, many thanks for your kind response and question. I would just take the precipitate from your first reaction and add ethanol (e.g. you can start with 20 ml per gram). Then heat the mixture to boiling and slowly add more ethanol until everything (hopefully) dissolves. Filter if necessary and let the clear solution stand at room temperature over night. There is no guarantee that this recrystallization method works, but it is certainly worth a try. With best wishes, Frank Edelmann
P.S. You might want to check the attached literature reference. The authors describe here a related amino acid-derived Schiff base and report that the product was recrystallized from chloroform / ethanol.
Owh i see. Thank you for your help Mr. Frank Edelmann. Really appreciate it ^^
From IR you can get information about functional groups.
Above 1600 cm-1 group frequency str. bands are observed. Below 1600 cm-1 is the finger print region where stretching and bending vibrations are mixed together.
IR(v max): 3500-3054 broad(OH & NH mixed together),1694(C=O), 1606,C=N),1580(C-C ) cm-1.
Dear Fatin,
We should agree with the above all answers from experts. To me, the spectrum correlates the desire product. One thing I would like to know is, Have you noticed the complete conversion of starting materials to product through TLC (Staining with different reagents also may be helpful to observe conversion), purified the product ? Sometimes interpretation of spectrum of crude mass is less helpful. And sometimes the moisture content of the reagent used for recording FTIR may misguide. So, better to get mass or NMR spectrum if possible. Or, least I would suggest to monitor through TLC using stains.
- Badges
- Science topic
- Similar topics
- Engineering
- Materials Engineering
- Powders