Much of what you say in the post-lab is guided by your NMR spectrum. Assign the
ID: 1006575 • Letter: M
Question
Much of what you say in the post-lab is guided by your NMR spectrum. Assign the peaks in your spectrum by: (1) drawing what you think the structure of the product is directly on your spectrum; (2) identifying the protons with code letters (e.g., "Ha", "Hb", "Hc", etc.), but grouping protons that give rise to the same signal under the same label; (3) writing "Ha", "Hb", "Hc", etc., near the appropriate peaks so that the assignment is clear; (4) identifying impurity peaks. The sketch shows the correct format applied to the NMR spectrum of 2-ethylanisole. You should discuss how you arrived at the assignments (i.e., explain the chemical shift, splitting and integration) in the text of your post-lab conclusion, but the assignments themselves must be written directly on the spectrum to be submitted with your post-lab.Explanation / Answer
Hd He Hf and Hg represents H atoms attached to aromatic ring. The chemical shift for such protons is in the range 6.7 ti 8.2 ppm. Hg is a diublet as it is coupled to Hf. He is tripplet as it is coupled to Hd and Hf. Hf is a triplet as it is coupled to He and Hd. Hd is doublet as it is coupled to He.
Ha represents H atom attached to methoxy C atom. Hence, it is high chemical shift of around 3.8 ppm. It is singlet as it is not coupled to any other proton. Hb is H attached to methyl group with chemical shift of 2.7 ppm. It is a quatret as it is coupled to 3 protons of methyl group. Hc represents H atoms attached to methyl group with chemical shift of 1.0 ppm. It is a triplet as it is coupled to 2 protons.
Based on the number of protons of each type the ratio of the integrals of peaks is Ha : Hb : Hc : Hd : He : Hf : Hg = 3 : 2 : 3 : 1 : 1 : 1 :1.
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