
Concept explainers
Interpretation:
Given that at room temperature the 1HNMR spectrum of N,N-dimethylformamide shows three peaks at 2.9 δ (singlet, 3H), 3.0 δ (singlet, 3H) and 8.0 δ (singlet, 1H). With increase in temperature the two singlets at 2.9 δ and 3.0 δ slowly merge together. At 180oC, the 1HNMR spectrum shows only two peaks at 2.95 δ (singlet, 6H) and 8.0 δ (singlet, 1H). This temperature dependence behavior is to be explained.
Concept introduction:
If two methyl groups attached to an atom in a single bond are non-equivalent because of a barrier to rotation of a single bond then the two methyl groups will give separate signals in 1HNMR. However if the barrier is not there, free rotation becomes possible, the methyl groups become inter-convertible and the two signals will merge to a single signal.
To explain:
The temperature dependence behavior observed in the 1HNMR spectrum of N,N-dimethylformamide is to be explained.

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Chapter 26 Solutions
Organic Chemistry
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