核磁共振PPT教学课件
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Frequency (n): the number of full cycles of a wave that pass a point in a second
Hertz (Hz): the unit in which radiation frequency is reported; s-1 (read “per second”)
When placed in a strong external magnetic field of strength B0, however, interaction between nuclear spins and the applied magnetic field are quartered, with the result that only certain orientations of nuclear magnetic moments are allowed
radio frequency
i nfra re d
ul tra viol e t -vi si ble
Absorption of Electromagnetic Radiation Results
in Transition Be tween
nuclear s pin energy levels
vibrational energy levels
electronic energy levels
13-4
A pictorial view of UV/Vis
UV/Vis radiation is measured in nm (wavelength)
13-5
IR Spectroscopy IR radiation is measured in cm-1 This is actually a frequency. Remember that frequency and wavelength are inversely proportional.
13-6
NMR Spectroscopy
NMR uses radiowaves, measured in MHz
13-7
Nuclear Spin States
Any atomic nucleus that has an odd mass, an odd atomic number, or both has a spin and a resulting nuclear magnetic moment. The allowed nuclear spin states are determined by the spin quantum number, I , of the nucleus. A nucleus with spin quantum number I has 2I + 1spin states. If I = 1/2, there are two allowed spin states
spin +1/2 (aligned with th e applied field
• hydrogens using 1H-NMR spectroscopy • carbons using 13C-NMR spectroscopy • phosphorus using 31P-NMR spectroscopy
13-9
Nuclear Spin States
Spin quantum numbers and allowed nuclear spin states for selected isotopes of elements common to organic compounds
Nuclear Magnetic Resonance
Chapter 13
13-1
Electromagnetic Radiation
Electromagnetic radiation: light and other forms of radiant energy • = c & E = h
Wavelength (): the distance between consecutive identical points on a wave
Eleme nt
1H
nuclear s pin
quantum 1/2
number (I )
2H 12C 13C 1 0 1/2
14N 16O 10
31P 32S 1/2 0
number of 2 3 1 2 3 1 2 1 spin states
13-10
Nuclear Spins in B0
Within a collection of 1H and 13C atoms, nuclear spins are completely random in orientation
13-8
Molecular Spectroscopy
Nuclear magnetic resonance (NMR) spectroscopy: a spectroscopic technique that gives us information about the number and types of atoms in a molecule, for example, about the number and types of
13-2
Electromagnetic Radiation
Wavelength
13-3
Molecular Spectroscopy
We study three types of molecular spectroscopy
Region of the ቤተ መጻሕፍቲ ባይዱl e ct rom agne t ic
Spectrum
13-11
Nuclear Spins in B0
For 1H and 13C, only two orientations are
allowed. higher
energy state
spin -1/2
(aligned against
th e applied field
Energy
lower energy state
Hertz (Hz): the unit in which radiation frequency is reported; s-1 (read “per second”)
When placed in a strong external magnetic field of strength B0, however, interaction between nuclear spins and the applied magnetic field are quartered, with the result that only certain orientations of nuclear magnetic moments are allowed
radio frequency
i nfra re d
ul tra viol e t -vi si ble
Absorption of Electromagnetic Radiation Results
in Transition Be tween
nuclear s pin energy levels
vibrational energy levels
electronic energy levels
13-4
A pictorial view of UV/Vis
UV/Vis radiation is measured in nm (wavelength)
13-5
IR Spectroscopy IR radiation is measured in cm-1 This is actually a frequency. Remember that frequency and wavelength are inversely proportional.
13-6
NMR Spectroscopy
NMR uses radiowaves, measured in MHz
13-7
Nuclear Spin States
Any atomic nucleus that has an odd mass, an odd atomic number, or both has a spin and a resulting nuclear magnetic moment. The allowed nuclear spin states are determined by the spin quantum number, I , of the nucleus. A nucleus with spin quantum number I has 2I + 1spin states. If I = 1/2, there are two allowed spin states
spin +1/2 (aligned with th e applied field
• hydrogens using 1H-NMR spectroscopy • carbons using 13C-NMR spectroscopy • phosphorus using 31P-NMR spectroscopy
13-9
Nuclear Spin States
Spin quantum numbers and allowed nuclear spin states for selected isotopes of elements common to organic compounds
Nuclear Magnetic Resonance
Chapter 13
13-1
Electromagnetic Radiation
Electromagnetic radiation: light and other forms of radiant energy • = c & E = h
Wavelength (): the distance between consecutive identical points on a wave
Eleme nt
1H
nuclear s pin
quantum 1/2
number (I )
2H 12C 13C 1 0 1/2
14N 16O 10
31P 32S 1/2 0
number of 2 3 1 2 3 1 2 1 spin states
13-10
Nuclear Spins in B0
Within a collection of 1H and 13C atoms, nuclear spins are completely random in orientation
13-8
Molecular Spectroscopy
Nuclear magnetic resonance (NMR) spectroscopy: a spectroscopic technique that gives us information about the number and types of atoms in a molecule, for example, about the number and types of
13-2
Electromagnetic Radiation
Wavelength
13-3
Molecular Spectroscopy
We study three types of molecular spectroscopy
Region of the ቤተ መጻሕፍቲ ባይዱl e ct rom agne t ic
Spectrum
13-11
Nuclear Spins in B0
For 1H and 13C, only two orientations are
allowed. higher
energy state
spin -1/2
(aligned against
th e applied field
Energy
lower energy state