N.M.R. Spectroscopy Flashcards
What does NMR stand for?
Nuclear Magnetic Resonance
What can NMR spectroscopy give details about?
The position of 13C or 1H atoms in a molecule
What is used to calibrate the HNMR and CNMR spectrum?
TMS (tetramethylsilane) (Si(CH3)4
Why is TMS a suitable standard?
Signal away from all the others (strong but only gives one)
Non toxic
Inert/unreactive
Low boiling point (so easy to remove)
Why is CDCl3 a suitable solvent for HNMR, despite an H being present? (deuterium)
It is 2^H
As it is an even number, the spins cancel out
Why must samples for HNMR be dissolved in a sample free of H1 atoms?
The H1 from the solvent would be present on the reading and so throw it
How are the samples for HNMR spectra obtained?
Samples are dissolved in CCl4 (non polar) or deuterated solvents (e.g. CDCl3 (polar) or D2O/heavy water)
