Introduction to Nuclear Magnetic Resonance—NMR Principle of NMR

Introduction to Nuclear Magnetic Resonance---NMR Principle of NMR

without Magnetic　 Field In the Magnetic Field B 0 Magnetic Nuclei In the absence of the field B 0, the Magnetic nuclei in the sample are oriented randomly. In the magnetic field, they must adopt either the aligned orientation(of lower energy) or the opposed orientation(of higher energy).

without Magnetic　 Field In the Magnetic Field B 0 Magnetic Nuclei Energy Level E hv In the absence of B 0 the magnetic nuclei all have the same energy. When B 0 is applied, the aligned and opposed orientations correspond to different energies, the energy difference, E , having the dimension hv.

without Magnetic　 Field In the Magnetic Field B 0 Magnetic Nuclei E=h E When the nuclei(in the magnetic field) are irradiated with radio-frequency(RF) energy of the appropriate frequency, some of them undergo transitions from the aligned to the opposed orientations and vice versa. （Resonance!!!)　 Resonance condition : W(2兀f )=r. B 0 　f=RF, r= Gamma ratio, 　　　

Field-frequency relationship Energy Level E 300 MHz 7. 0 T 500 MHz 11. 4 T 800 MHz 18. 8 T

Magnetic moment(1) 1 If both the mass number(A) and the atomic number(Z) are even, I = 0 (No NMR signal) 12 C, 16 O 2 If (A) is odd and (Z) is odd or even, I will have halfintegral values. I =1/2, 3/2, 5/2 etc 1 H, 19 F, 29 Si, 11 B(3/2), 17 O(5/2) 3　If (A) is even and (Z) is odd, I will have integral value 1, 2, 3 etc. 14 N, 6 Li,

Magnetic moment(2) 1 H nucleus 1 proton magnetic 2 H nucleus 1 proton 1 neutron 4 He nucleus 2 protons 2 neutrons magnetic Non-magnetic 12 C nucleus 6 proton 6 neutrons 13 C nucleus 6 protons 7 neutrons Non-magnetic

Typical Magnetic Isotopes Resonance condition: W(2兀f )=r. B 0 1 H : 2 x 3. 14 x 400(25. 12) = 26. 75 x 9. 39(25. 118) 13 C: 2 x 3. 14 x 100. 533(63. 13)= 6. 73 x 9. 39(63. 19)

Sensitivity Table relative to 13 C

Block diagram of NMR instrument RF Oscillator RF Gate Pulse Programmer SCM RF Power Amplifier Probe Display Computer Printer AD Converter Phase Sensitive detector Preamplifier

Composition of NMR instrument ECA 500　NMR JEOL LTD

The NMR information 1) 2) 3) 4) 5) Chemical Shift Spin-Spin Coupling Intensity(Area) of Signal Relaxation(T 1, T 2) NOE

Chemical Shift TMS: Tetra-　　　　　 Methyl-Silane TMS Chemical　shift

Chemical Shift Table -CH 2 - 13 C Chemical Shift

Spin-Spin Coupling CH 3 -CH 2 -O-C-CH=CH-CH 3 A C O E D A B B C E D

Intensity(Area) Information

1. 02 0. 99 1. 00 1. 02 1. 00 1. 99 2. 03 2. 02 Integration

Various measurement methods 1 dimension (1 H, 13 C, DEPT, ……. ) 2 dimension (COSY, NOESY, TOCSY, HMBC, HMQC, …) 3 dimension (COSY, NOESY, TOCSY, HMBC, HMQC, …) 4 dimension (COSY, NOESY, TOCSY, HMBC, HMQC, …)

1 dimensional NMR(1 D NMR) 50 mg samples, Solvent acetone-d 6

2 dimensional NMR Y X : 1 H, 13 C, 1 H Y : 1 H, X 1 H, 15 N

2 dimensional NMR

2 dimensional NMR(2 D NMR) Methylene carbon of B, G, H, J is shown two correlation signals with Proton , this methylene proton is non-equivalent.

3 dimensional NMR Y X X : 1 H Y: 13 C Z Z : 31 P

Three Dimensional NMR • 3 D NMR is standard with the Eclipse+ NMR spectrometer

4 -Dimensional NMR Data Processing • Delta’s Standard Multi-Dimensional NMR Data processing tool uses the same user interface as 1 D and 2 D data processing

4 dimensional NMR X Y Z A X : 1 H Y : 13 C Z : 15 N A : 31 P

Application field of NMR Liquid NMR Solid NMR Imaging Structure elucidation of 　natural product , polymer etc Stereo- structure elucidation protein etc Molecular diffusion Relaxation measurement Dynamic measurement Structure elucidation Stereo-structure information Relaxation information Spin density Relaxation information Dynamic information (Flow imaging)