Which of the following chemical shift values could plausibly correspond to the protons in divinyl ether (CH₂=CH–O–CH=CH₂)

Predict the theoretical number of different NMR signals produced by each compound, and give approximate chemical shifts. Point out any diastereotopic relationships.

a. 2-bromobutane

b. cyclopentanol

Which of the labeled protons absorbs energy most upfield in the 1H NMR?

Which of the labeled hydrogens will be most de-shielded?

Which compound possesses a hydrogen with the highest chemical shift for its 1H NMR signal?

Predict the approximate chemical shifts of the protons in the following compounds.

(c) CH₃–O–CH₂CH₂CH₂Cl

(d) CH₃CH₂–C≡C–H

The NMR spectrum of toluene (methylbenzene) was shown in Figure 13-11.

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(a) How many different kinds of protons are there in toluene?

(b) Explain why the aromatic region around d7.2 is broad, with more than one sharp absorption.

Predict the chemical shifts of the protons in the following compounds.

(a)

(b)

In a 300-MHz spectrometer, the protons in iodomethane absorb at a position 650 Hz downfield from TMS.

(a) What is the chemical shift of these protons?

(b) What is the chemical shift of the iodomethane protons in a 60-MHz spectrometer?

(c) How many hertz downfield from TMS would they absorb at 60 MHz?