CHEM 455

1. How many signals would you expect to find in the 1H NMR spectrum of each of the following compounds? 2. Describe the appearance of the 1H NMR spectrum of each of the following compounds. How many signals would you expect to find, and into how many peaks will each signal be split? (a) ClCH2OCH2CH3 (b) CH3CH2OCH3 (c) CH3CH2OCH2CH3 (d) p-Diethylbenzene (e) ClCH2CH2OCH2CH3 3. How many signals would you expect to see in the 13C NMR spectrum of each of the following compounds? (a) Propylbenzene (b) Isopropylbenzene (c) 1,2,3-Trimethylbenzene (d) 1,2,4-Trimethylbenzene (e) 1,3,5-Trimethylbenzene 4. Consider carbons x, y, and z in p-methylanisole. One has a chemical shift of δ20 ppm, another has δ 55 ppm, and the third δ 157 ppm. Match the chemical shifts with the appropriate carbons. 5. Which one of the C5H8 isomers shown has its max at the longest wavelength? 6. Each of the following compounds is characterized by a 1H NMR spectrum that consists of only a single peak having the chemical shift indicated. Identify each compound. 7. Each of the following compounds is characterized by a 1H NMR spectrum that consists of two peaks, both singlets, having the chemical shifts indicated. Identify each compound. 8. Deduce the structure of each of the following compounds on the basis of their 1H NMR spectra and molecular formulas: 9. Identify each of the C4H10O isomers on the basis of their 13C NMR spectra: 10. A compound Q, C5H8O shows IR absorption at 3600 and 3300 cm-1. Its 1H NMR spectrum contained singlets at δ1.5, 2.2, 2.9 (broad) ppm in the ratio of 6:1:1. i) Calculate the unsaturation index of this compound ii) Identify the bond responsible for each of the absorption peaks at 3600 and 3300 cm-1 in the IR spectrum iii) The 1H NMR obtained showed peaks at 2.9 ppm (singlet), 2.2 ppm (singlet) and1.5 ppm (singlet). Suggest with reason the identity of peaks based on the signals and multiplicity iv) Draw the structural formula of compound Q 11. An organic compound A has empirical formula C2H4O. Spectra of the compound A are shown below Use this information to answer the following questions. Mass spectrum for compound A