1H NMR spectrum of: All signals in spectrum are due to a proton (hydrogen atom). Every H in the molecule must be represented. Likewise, every signal is attributable to one (or more) Hs. s* s* d d q d 1* 1* 2 2 1 3

Every 1H NMR contains 3 pieces of information you should use Every 1H NMR contains 3 pieces of information you should use. All the pieces must fit. The first is: chemical shift (d, in ppm from TMS). d is the frequency unit for NMR. The d of a signal will tell you about the electronic environment of the H causing the signal. In essence, this tells you about the atom that H is bonded to. Downfield upfield s* s* d d q d 1* 1* 2 2 1 3 TMS Chemical shift

The spectrum can be broken down into regions of chemical shift The spectrum can be broken down into regions of chemical shift. (Region for bolded H). s* s* d d q d 1* 1* 2 2 1 3 Chemical shift

Things to watch out for: 1) OH and NH protons move over the entire spectrum and usually don’t “couple” and may be washed out by addition of D2O to the sample. If the signal can be washed out with D2O, it will be so indicated by an asterisk (*). 2) The regions are additive – if a H is both on a C that is bonded to an O and is also bonded to an sp2C, it will move farther downfield. s* s* d d q d 1* 1* 2 2 1 3 Chemical shift

Things to watch out for: 3) Inside any one region, CH3 is upfield of CH2 which is s* s* d d q d 1* 1* 2 2 1 3 Chemical shift

The second important piece of information in the 1H NMR spectrum is “integration”. Integration is a measure of the intensity of the signal. The area under the peak of a 1H NMR signal is directly proportional to the number of H causing the signal. This information must be given to you – you can’t judge it based on height of the signal alone. The number of H shown should either match the number in the molecule or be a multiple. For example, the integration shown below could apply to a molecule with 9, 18, 27, etc. Hs. s* s* d d q d 1* 1* 2 2 1 3

The second important piece of information in the 1H NMR spectrum is “integration”. Integration is a measure of the intensity of the signal. The area under the peak of a 1H NMR signal is directly proportional to the number of H causing the signal. This information must be given to you – you can’t judge it based on height of the signal alone. When do two or more Hs give the same signal? When they are equivalent. s* s* d d q d 1* 1* 2 2 1 3

Atomic equivalency test: To decide if two different H (or other atom) are equivalent, replace each in turn with X. s* s* d d q d 1* 1* 2 2 1 3

The final piece of information provided in a 1H NMR spectrum is the coupling, or splitting, pattern of individual signals. This provides information regarding the number of magnetically active nuclei near to the H causing the signal. Usually the other magnetically active nuclei need to be within 3 sigma bonds (or less) of the H causing the signal. Common abbreviations: bs: broad singlet s: singlet d: doublet t: triplet q: quartet dd: doublet of doublets m: multiplet s* s* d d q d 1* 1* 2 2 1 3

s* s* d d q d 1* 1* 2 2 1 3

s* s* d d q d 1* 1* 2 2 1 3

Note that equivalent H do not couple to one another. Therefore, the CH3 give a single signal and none of the three H split the others. s* s* d d q d 1* 1* 2 2 1 3

s* s* d d q d 1* 1* 2 2 1 3

Also, note that OH and NH protons may couple with near neighbors but, then again, they may not. Analyze the spectrum both ways. s* s* d d q d 1* 1* 2 2 1 3

2 3 3

3 2 3

Bs septet doublet 1* 1 6

t quint t 1* 2 2 3

S* d m m m t q quint t 1* 1 1 2 2 2 2 2 3

170.16 161.85 135.59 134.98 129.95 123.41 119.08 117.61 112.65 64.82 26.78 20.71 14.21