Hi all,
In the publication "Rapid killing of bacteria by a new type of photosensitizer", which was published on Appl Microbiol Biotechnol. 2017 Jun;101(11):4691-4700. DOI: 10.1007/s00253-017-8133-8. When I went through the NMR spectra, particularly the Proton NMR spectrum of ZnPc(TAP)412+, there is a peak at 3.1ppm which is not integrated nor mentioned. Could anyone of you guys please help me in understanding that peak? It would be great if the impurity can be pointed out specifically. I am attaching the supplementary file here so that it is easy for you. (page no:5, Figure S1b).
Regards
Sidharth
Dear Sidharth Thulaseedharan Nair Sailaja I'm not an expert in this chemistry, but when you look at the preparation, you find that the original precipitate is dissolved in methanol and precipitated again by adding diethyl ether. Thus I think that the most likely impurity is some remaining methanol. The methyl group of methanol would give the peak at 3.1 ppm (depending on the solvent) and the OH resonance of methanol would be hidden under the broad peak at 5.92-4.54 ppm. I'm not 100% certain, but I think it's a plausible explanation.
Typical impurites of NMR spectras you can find here:
Article NMR Chemical Shifts of Trace Impurities: Common Laboratory S...
I think if you compare this data, with the supporting you find the remaining solvents, and i guess i would be the solvents Frank proposed.
Hi, Siddhu. Common NMR impurities for different solvents (for both proton and C13) can be found in this attached file. I assume the peak around 3.1 is from the methyl protons of methanol (if present during the course of the reaction), this peak position can be changed depending upon differnt solvents.
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