a.[2]
Explain the use of tetramethylsilane (TMS) and deuterated solvents such as CDCl3\text{CDCl}_3CDCl3 in proton (1H^1\text{H}1H) NMR spectroscopy.
b.[6]
An organic compound K is analysed using a combination of analytical techniques. The data obtained is shown below:
- Elemental analysis by mass: C: 55.38%, H: 7.69%, O: 36.92%
- Mass spectrum: Molecular ion peak at m/z=130.0m/z = 130.0m/z=130.0
- IR spectrum: Absorptions at 1715 cm-1 and 1740 cm-1
- Proton NMR spectrum data:
- δ=4.2 ppm\delta = 4.2\text{ ppm}δ=4.2 ppm, quartet, integration = 2H2\text{H}2H
- δ=3.4 ppm\delta = 3.4\text{ ppm}δ=3.4 ppm, singlet, integration = 2H2\text{H}2H
- δ=2.2 ppm\delta = 2.2\text{ ppm}δ=2.2 ppm, singlet, integration = 3H3\text{H}3H
- δ=1.3 ppm\delta = 1.3\text{ ppm}δ=1.3 ppm, triplet, integration = 3H3\text{H}3H
Determine the structure of compound K. Show all your reasoning.
