Hi everyone. This is my ftir data for the schiff base derived from phenylalanine and terephthaldehyde. I got some confiusion about the peak that show the formation of new bond of C=N. Because based on the ir spectrum table for the C=N it suppose to be at range between 1690-1640 but most of the article that i read, the formation of C=N is not in the range between that value. So, i want to know either my C=N value is at strong peak of 1582 or i need to identify other peak that is near to the 1582 value?
It is not correct to say that C=N bond frequency will be in between 1640-1690 cm-1. Most of the time it is close to 1600cm-1 and it undergoes a negative shift during the complexation with metal ion. In the present case it is a combination of more than one band and the frequency of the imine is close to 1620cm-1.
@sengottuvelan oh i see. Is it correct C=N is at peak 1582 since it is quite far from 1620?
You need not go by the values indicated by the instrument. The very high intense peak which is close to the x-axis may not be shown by the instrument. What you have is a combination of more than one peak and the lesser intense one is indicated in the spectrum
The peak that correlates to the peak of C=N observed in IR group frequency region at 1620 to 30 cm-1 and is sharp. In the presenr spectrum it seems to be merged with C=O str. band.
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