Chapter 14.6, Problem 13ATS

The NMR spectrum of bromocyclohexane indicates a low field signal (1H) at δ 4.16. To room temperature, this signal is a singlet, but at -75 ° C it separates into two peaks of unequal area (but totaling one proton): δ 3.97 and δ 4.64, in ratio 4.6: 1.0. How do you explain the doubling in two peaks? According to the generalization of the previous problem, what conformation of the molecule predominates (at -75 ° C)? What percentage of the molecules does it correspond to? Solve all parts otherwise down vote and hand written solution

Compound 2 has molecular formula C6H12. It shows three signals in the 1H-NMR spectrum, one at 0.96 ppm, one at 2.03 ppm, and one at 5.33 ppm. The relative integrals of these three signals are 3, 2, and 1, respectively. Provide structure for compound 2, explain how you reached your conclusion.

1Compound 1 has molecular formula C7H16. It shows three signals in the 1H-NMR spectrum, one at 0.85 ppm, one at 1.02 ppm, and one at 1.62 ppm. The relative integrals of these three signals are 6, 1, and 1, respectively. Compound 2 has molecular formula C7H14. It shows three signals in the 1H-NMR spectrum, one at 0.98 ppm, one at 1.36 ppm, and one at 1.55 ppm. The relative integrals of these three signals are 3, 2, and 2, respectively. Propose structures for compounds 1 and 2, explaining how you reach your conclusion.

Saturated aldehyde Aromatic aldehyde At what position would you expect to observe IR absorption for the carbonyl groups in the following molecules? Infrared Absorptions of Some Aldehydes and Ketones. Carbonyl type Absorption cm-1 1730 1705 Example CH3CHO PhCHO a,ẞ-Unsaturated H2C=CHCHO 1705 aldehyde Saturated ketone CH3 COCH3 1715 Cyclohexanone 1715 Cyclopentanone 1750 Cyclobutanone Aromatic ketone 1785 PhCOCH3 a,ẞ-Unsaturated ketone H2C=CHCOCH3 1685 1690 Molecule #1: Molecule #2: CHO CHO CH3 cm-1 cm -1

Compound 1 has molecular formula C7H16. It shows three signals in the 1H-NMR spectrum, one at 0.85 ppm, one at 1.02 ppm, and one at 1.62 ppm. The relative integrals of these three signals are 6, 1, and 1, respectively. Compound 2 has molecular formula C7H14. It shows three signals in the 1H-NMR spectrum, one at 0.98 ppm, one at 1.36 ppm, and one at 1.55 ppm. The relative integrals of these three signals are 3, 2, and 2, respectively. Propose structures for compounds 1 and 2, explaining how you reach your conclusion.

A ¹H NMR spectrum is shown for a molecule with the molecular formula of C9H10O2. Draw the structure that best fits this data. 11 10 9 8 2H 2H 7 6 5 4 3 3H 3H 2 ppm Q

The 13C-NMR spectrum of 3-methyl-2-butanol shows signals at 17.88 (CH3), 18.16 (CH3), 20.01 (CH3), 35.04 (carbon-3), and 72.75 (carbon-2). Account for the fact that each methyl group in this molecule gives a different signal.

Propose a structural formula for the analgesic phenacetin, molecular formula C10H13NO2, based on its 1H-NMR spectrum.

How would you use NMR (either 13C or 1H) to distinguish between the following pairs of isomers?