Question

10. (8 points) For each of the following molecules predict the "C and 'H NMR spectra. For the "C NMR predict the number of peaks and the shift. For the 'H NMR you will need to predict the shift, multiplicity, and integration of the peaks. CH3 HC не ең, H₃C =O % b-CH3 11. (6 points) Propose a structure for a compound with the chemical formula C.H.Cl, that fits the following 1H NMR data 2.18 8 (3H, singlet) 4.16 8 (2H, doublet) 5.71 8 (1H triplet)

Answer 1

CH Singlet 701701 Singlet 7.07 701 PPM

21.3 CH3 135.4 128.9 128.9 128.9 S D 135.47 128.9 CH3 21.3 140 ' 120 ' 100 ' 80 ' PPM 60 ' 40 ' 20

PPM

27.4 38.4 | 52.5 17.20 27401 27.4 180 160 180 120 100 80 60 40 20 PPM

Degree of Unsaturation (DOU) is also known as Double Bond Equivalent. If the molecular formula is given, DoU can be calculated as follows

DoU   =   2C+2+N−X−H

               2

C is the number of carbons

N is the number of nitrogens

X is the number of halogens (F, Cl, Br, I)

H is the number of hydrogens

Molecular formula C4H6Cl2

Therefore sites of unsaturation = [(2*4)+2-6-2]/2 = 1

¹H NMR data:

NMR peak value (ppm)	Multiplicity	Protons	Indication
2.18	singlet	3H	CH3 attached to quaternary carbon
4.16	Doublet	2H	CH2 attached to CH and chlorine
5.71	triplet	1H	CH attached to CH2 and alkene

Therefore, structure of the molecule is

CI Chemical Formula: C4H6Cl2