Spectroscopy Flashcards
What is nmr spectroscopy
Interaction of low energy radio waves and nuclei within a strong magnetic field
Types of nmr
Carbon 13
H (proton)
Carbon 13 nmr
Peak for every different carbon environment ( equivalent c atom)
H nmr
A peak for each set of hydrogen environments
Integration ratio
Each signal is proportional to the number of equivalent H atoms
Spin spin coupling
High resolution h nmr each signal can be split into further lines depending on neighbouring carbon atoms
Splitting of peak
Number of inequivalent Hs on neighbouring c atoms + 1
NMR solvents
CDCl3
D2O identify oh and amide
Calibration compound
Tetramethylsilane added to calibrate the spectrum
1 NMR peak at 0
Inert and volatile doesn’t react
Why is TMS used
Signal is away from all the others
Only gives one strong signal
Non toxic
Inert
Low bo so can be removed easily
Electronegativity effect on nmr
The more electronegative an atom bonded to a carbon the greater the ppm
What is chromatography
Analytical tech that separates components in a mixture between a mobile phase and stationary phase
How does a solid stationary phase separate
Adsorption
How does liquid stationary phase separate
Relative solubility
TLC paper
Contains silica which is very polar