NMR Spectroscopy Alexej Jerschow, NYU Chemistry 1
Overview Larmor Eq Chemical Shift J-coupling 1D NMR spectra 2D NMR spectra (Imaging) Alexej Jerschow, NYU 2
Alexej Jerschow, NYU 3
For further reading: Alexej Jerschow, NYU 4
NMR in the sciences Proteins, DNA, drugs Glasses, semiconductors, materials Imaging Microscopy Quantum Computing Alexej Jerschow, NYU 5
Protein Data Bank www.pdb.org E x p. T e c h. X-ray Diffraction and other As of 01-Apr-2003 Molecule Type Proteins, Peptdes, and Viruses Protein/ Nucleic Acid Complexes Nucleic Acids Carbohydrates total 15944 766 662 14 17386 NMR 2548 89 506 4 3147 Total 18492 855 1168 18 20533 Alexej Jerschow, NYU 6
Principles of NMR Spectroscopy The nucleus has a tiny magnetic moment The electron cloud determines the chemical shift Alexej Jerschow, NYU 7
Measurement Larmor frequency ω=γβ Alexej Jerschow, NYU 8
Superconducting magnet creates the large magn. field. Alexej Jerschow, NYU 9
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Facilities Solid 400 MHz in lab. Liquid 400 and 500 MHz in department. 800eds, solid 750 and soon a 900 MHz at the New York Struct. Biol. Ctr. Alexej Jerschow, NYU 11
Magnetically active isotopes Alexej Jerschow, NYU 12
Spin Alexej Jerschow, NYU 13
Energy levels 2I+1 energy levels Alexej Jerschow, NYU 14
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Resonance Frequencies, gyromagnetic ratios Alexej Jerschow, NYU 16
Magnetic Field Strengths Given in Tesla (=10 4 gauss) Given as the 1 H resonance frequency in MHz Alexej Jerschow, NYU 17
RF frequencies Figure 12.3: Class radiation Alexej Jerschow, NYU 18
Sensitivity of NMR Alexej Jerschow, NYU 19
Chemical shift Alexej Jerschow, NYU 20
Chemical shift Alexej Jerschow, NYU 21
Alexej Jerschow, NYU 22
RF frequencies Alexej Jerschow, NYU 23
Chemical Shift ppm scale Alexej Jerschow, NYU 24
Chemical shift Alexej Jerschow, NYU 25
Chemical Shift for certain groups Alexej Jerschow, NYU 26
Alexej Jerschow, NYU 27
J-Coupling (scalar coupling) Mainly through three bonds max. Alexej Jerschow, NYU 28
Heteronuclear J-coupling Alexej Jerschow, NYU 29
J-coupling, energy shift Alexej Jerschow, NYU 30
2D Correlation Spectroscopy Based on Through-bond interactions (J-couplings) COSY Through-space interactions (dipolar couplings) NOESY 1D-spectrum along the diagonal Cross-peaks indicate either spatial proximity or chemical bond Alexej Jerschow, NYU 31
Multidimensional NMR Alexej Jerschow, NYU 32
NOE struct. determ. Alexej Jerschow, NYU 33
COSY Alexej Jerschow, NYU 34
NOESY Alexej Jerschow, NYU 35
COSY, Lysine α HNs HN β γ δ Alexej Jerschow, NYU 36
NOESY, Lysine-Ala β γ β δ α α HNs HN Alexej Jerschow, NYU 37
COSY, Histidine HN α β γ δ ε HNs Alexej Jerschow, NYU 38
COSY, Alanine β α γ δ ε HNs HN Alexej Jerschow, NYU 39
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The way of coupling for COSY, TOCSY and NOESY: Alexej Jerschow, NYU 41
NOESY, Ile-Ala Alexej Jerschow, NYU 42
Exercise: NOESY, Ile-His Alexej Jerschow, NYU 43
From: Horst Friebolin, One- and Two-Dimensional NMR Spectroscopy Alexej Jerschow, NYU 44
These are sagittal images of the brains of a control and Alzheimer's patient, showing the area within the parietal lobe where each spectrum was acquired. Within an Alzheimer's patient's brain the concentration of N-Acetylaspartate is found to decrease while the myo-inositol increases, when compared to normal concentrations. Rose SE, de Zubicaray GI, Wang D, Galloway GJ, Chalk JB, Eagle SC, Semple J, Doddrell DM. Magnetic Resonance Imaging 1999:17; 291-299. Alexej Jerschow, NYU 45
Quantification of fat in the liver 1 H NMR spectrum of voxel in liver http://www.cmr.uq.edu.au/research/research.html Alexej Jerschow, NYU 46
Chemical-Shift Imaging NMR spectra of different parts of a sample are measured (non-invasively!) Fig. 2: Chemical shift imaging on an intact juneberry fruit. Sample dimensions: 15x15 mm, thickness of selected slice: 1mm, voxel dimensions for chemical shift measurement: 234x234x1000 µ m. The right parts of the figure show the NMR spectra of the voxel selected at the positions indicated in the left parts of the figure. The spectra show the different chemical compositions of the fruit pulp ( mainly carbohydrates) and the seed ( mainly oil/fat). (D.Gross, V. Lehmann, K. Zick and T. Oerther, Bruker Report 148/2000, p. 30) Alexej Jerschow, NYU 47