Nuclear Magnetic Resonance Spectroscopy Flashcards
what are the two types of nmr
- carbon nmr
- proton nmr
how does nmr work
a magnetic field is applied to a sample which is surrounded by a source of radio waves which will generate an energy change in the nucleus in the sample that can be detected
electromagnetic energy is emitted which can be interpreted by a computer
carbon nmr
there is one signal peak for each set of equivalent carbon atoms
what is the chemical shift
the difference between the resonant frequency of a nucleus and a standard reference
what is proton nmr
one signal for each set of equivalent H atoms
spin spin coupling
n+1 rule
n+1 rule
singlet
doublet
quartet
multitet
what are samples dissolved in
inert solvents with no HYDROGEN ATOMS
examples of solvents
ccl4
cdcl3
cdcl3 is used for
polar compounds
ccl4 is used for
non polar
what does d stand for in cdcl3
deuterium it is a stable isotope of hydrogen
calibration and the shift
WHAT IS USED
tetramethylsilane is used (TMS)
Why is tms used
it only gives one signal
it signal is away from all other hydrogen signals
non toxic
inert
low bp so can be removed easily
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