13 C NMR SPECTROSCOPY OCR Chemistry F324 - 1.3 - Analysis
13C NMR SPECTROSCOPYOCR Chemistry F324 - 1.3 - Analysis
INTRODUCTION TO CARBON-13 SPECTROSCOPY
➤ Carbon-13 nuclei are ‘spin½’ nuclei, and can hence behave as a magnet.
➤ It can therefore be opposed / aligned to an external magnetic field.
➤ It is possible to oppose the direction by applying a specific amount of energy.
➤ Radio waves are used to supply the energy.
➤ This ‘flipping’ process is known as resonance condition.
EXAMPLE 1
➤ Ethanol:
➤ 2 peaks due to 2 different chemical environments
EXAMPLE 1
➤ Ethanol:
➤ 2 peaks due to 2 different chemical environments.
➤ The first carbon environment (the C on CH3) has the bond
➤ The peak around 20 shows a C-C is present.
➤ The peak around 60 shows a C-O is present.
➤ They are equal heights showing that there are an equal number of carbon environments.
EXAMPLE 2
➤ 1-methylethylpropanoate
➤ 2 peaks due to 2 different chemical environments.
➤ The first carbon environment (the C on CH3) has the bond
➤ The peak around 20 shows a C-C is present.
➤ The peak around 60 shows a C-O is present.
➤ They are equal heights showing that there are an equal number of carbon environments.