1559_ch10_175-19810/30/0518:09Page190 EQA 190.Chapter 10 USING NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY TO DEDUCE STRUCTURE Put them together to give 2-pentanol. OH CH3-CH2-CH2-CH CH methyls (=0.9)and the groups splittins them (=1.21.8 in E and =1.4 in F). 41.(a)The sketch show (chemical shifts in the spectrum are those actually found). Br-CH-O一Ch pm( (b)The sketch shows a singlet for the methyl and two close triplets for the-CH-CH-unit. The actual spectrum would show complications in the splitting of the latter because of the small spec Ci-O-CH]-CH]-Br Put them together to give 2-pentanol. Notice how both spectra E and F have had very distorted triplets around 0.9 for CH3 groups next to CH2’s. This distorted appearance is very common and is due to the closeness of the chemical shifts of the methyls ( 0.9) and the groups splitting them ( 1.21.8 in E and 1.4 in F). 41. (a) The sketch shows typical ethyl group signals (upfield triplet for the CH3 and downfield quartet for the CH2) and a very deshielded CH2 singlet due to attachment to two electronegative atoms (chemical shifts in the spectrum are those actually found). (b) The sketch shows a singlet for the methyl and two close triplets for the OCH2OCH2O unit. The actual spectrum would show complications in the splitting of the latter because of the small chemical-shift difference (refer to Section 10-8). We have ignored this effect and shown how the first-order spectrum would look. 4 3 2 1 0 ppm (δ) CH3 O CH2 CH2 Br 10 9 8 7 6 5 4 3 2 1 0 ppm (δ) Br CH2 O CH2 CH3 OH CH3 CH3 CH2 CH2 CH 190 • Chapter 10 USING NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY TO DEDUCE STRUCTURE 1559T_ch10_175-198 10/30/05 18:09 Page 190