CHM 2120 Lecture Notes - Lecture 3: Infrared Spectroscopy, Chemical Shift, Pi Bond
25 Nov 2016
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Du = 1 ring or a pi bond. 4 du = 1 ring and 3 pi bonds or a structure with 4 pi bond. Works the other way around too to find du from structure. The letters respond to intensity s=small m=medium v=variable. Frequency depends on bond strength and atomic mass. Low = frequency is being absorbed because they are the same frequency. It has an oh vibration (first one) that is very broad. D has a carbonyl, but no carbonyl stretch present. Just over 3000 means that carbon is sp3 hybridized not sp2. Just over 3000 means that there are frequencies going right above 3000 as well, very very close. Not a carbonyl because carbonyl is very strong, this is not. Not c=o, not b because there is sp3. There is both sp2 and sp3 present = d. No broad feature of oh present, not c. Peaks at around 3200 and just less than 3000.
