-
Nuclear Magnetic Resonance Spectroscopy
- Corresponds to an atom’s Nuclear Spin Energy State
- Deals with an atom’s nucleus and its spin orientation in a magnetic field (B0, aka H0)
-
2 Spin States
- alpha: aligned with B0
- beta: opposed to B0
-
Standard NMR Experiment
- 1. Dissolve sample in CDCl3 solvent (internal lock solvent)
- 2. Place in a strong magnetic field, causing speration of
- energy of spin states
- 3. Irradiate sample with short rf pulse, causing alpha spin state to flip to beta spin state
- 4. Allow nuclei to relax from beta to alpha spin state
- 5. Detect E released and mathematically process data
- 6. NMR Spectrum displayed as Intensity of Absorbance vs.Frequency (delta, chemical shift)
-
Internal Standard
TMS (tetramethylsilane, SiMe4) ppm = 0.00
-
Basic Information Obtained from 13C Spectra
- 1. Number of Signals
- Indicates # of different types of Cs, i.e. chemically non-equivalent Cs
- 2. Chemical Shift (delta)
- Indicates type of chemical environment of C
-
-
-
-
|
|
