Using the NMR spectrum-- for every peak discuss how its three properties (integr
ID: 520797 • Letter: U
Question
Using the NMR spectrum-- for every peak discuss how its three properties (integration, chemical shift, and splitting) agree with your proton assignment.
Integration
Shift
Splitting
Ha
1.00 (2H)
7.95
Doublet
Hb
1.52 (3H)
7.68-7.28
Multiplet
Hc
1.12 (2H)
2.984
Multiplet
Hd
1.65 (3H)
1.224
Multiplet
Using the NMR spectrum-- for every peak discuss how its three properties (integration, chemical shift, and splitting) agree with your proton assignment.
Integration
Shift
Splitting
Ha
1.00 (2H)
7.95
Doublet
Hb
1.52 (3H)
7.68-7.28
Multiplet
Hc
1.12 (2H)
2.984
Multiplet
Hd
1.65 (3H)
1.224
Multiplet
11 10 ppm 180 B) H H CA (B) H CH 7.95 7.68 to 7.28 2.984 1.224 Hz ppm. Int. Int Hz ppm 666.69 7.445 71 717.56 8.013 196 666.19 7.439 115 715.94 7.994 201 714.06 7.973 98 665.13 7.427 127 664.56 7.421 190 713.13 7.963 80 712.25 7.953 77 664.06 7.415 176 710.69 7.936 151 662.13 7.394 30 661.38 7.385 34 710.25 7.931 150 660.75 7.378 42 709.13 7.918 77 659.19 7.361 74 707.81 7.904 266 657.38 7.341 706.38 7.888 52 30 655.56 7.320 36 677.56 7.566 63 278.94 3.115 96 676.31 7.552 80 675.94 7.548 72 278.50 3.110 87 271.31 3.030 380 674.50 7.532 57 264.06 2.949 419 673.00 7.515 196 257.19 2.872 131 672.00 7.504 362 116.44 1.301 445 670.81 7.491 308 109.38 1.222 1000 669.69 7.478 172 668.69 7.467 160 101.94 1.139 356Explanation / Answer
There are two Ha protons. These are aromatic protons deshielded by the neighbouring carbonyl group and hence appear most downfield.. Each of these protons undergo ortho coupling with one of the vicinal Hb protons splitting into a doublet.
There are 3 Hb protons. They are also aromatic but appear a little upfield than Ha protons as they are away from the carbonyl group.. The multiplet is due to ortho coupling of two protons neighbouring to Ha protons and meta coupling of the third.
There are two Hc protons neighbouring to the carbonyl group and hence appear more downfield than the Hd protons (3). As there are 3 neighbouring protons, Hc appears as a quartet and Hd splits into a triplet because of two vicinal protons.
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