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Basic 1D information

Instruments and Experiments

Technique Descriptions

Basic One-dimensional NMR information

A. Sample Preparation.

We use 5 mm tubes, Kontes grade 897130 (N51 glass) or better, available from Fisher Scientific. For variable temperature work, use 897230 (Pyrex glass) or better. Do NOT use disposable grade tubes in ANY NMR since they are often irregular and could result in damage to the instrument. All samples must be dissolved in deuterated solvents in order for the field-frequency lock to function. 600 ul is the normal volume. Sigma -Aldrich is a supplier of deuterated solvents.

B. How much sample is required?

Proton - only 1-5 mg of a small molecule is necessary. Smaller amounts require longer scan times.

Carbon, direct observe- the table below is a guide for a small molecule (MW=334) on the 400SL. The 300wb is 2x less sensitive so the time required for the same amount of sample is 4x more. The detection limit can be lowered with the use of Shigemi tubes. See the Carbon training handout for more details. Please note: 2D HSQC is at least 15 times more sensitive than 1D carbon direct observe.

Sample Quantity Molarity (mM) Approximate Time Required
25 mg 75 5 min
7.5 mg 22.5 30 min
3 9 180 min
1.5 4.5 12 hrs

C. Where to take simple 1H and 13C spectra?

I want to do this experiment You should use this NMR Comments
1H routine 300NB or 400L 300NB is walk-on. 400L uses 10 minute time slots
1H but I have very little sample 500 Ascend, 500, or 400L during night time 500 Ascend has the best 1H sensitivity
13C direct observe including DEPT 500, 400SL or 300WB 500 has the best 13C sesnsitivity

 

Instruments and Experiments

Use the following table to determine which instrument to use for different experiments. This table reflects the experiments that have been setup and tested and for which a parameter set exists. This table is not complete; others are available. To see a complete list of experiments that have been setup and tested on each spectrometer, type rpar *.top from within Topspin while using the NMR.

Experiment 500 Ascend 500 400SL 400L 300wb 300nb
Variable Temperature possible possible
             
PROTON EXPERIMENTS            
1D proton
COSY  
FAST COSY  
J-Resolved    
2D NOESY /W ZQ suppression    
2D ROESY    
2D EASY-ROESY (tocsy suppressed)          
1D selective NOESY /w ZQ suppression    
2D TOCSY    
Selective TOCSY /w ZQ suppression    
Homonuclear decoupling    
Multi-fequency decoupling (MDEC)    
1H T1 measurement    
Kinetics  
2D EXESY  
Magnetization exchange      
diffusion and DOSY      
STD (ligand binding)          
water suppression (PURGE)      
water suppression (Ex. Sculpting)      
             
CARBON-PROTON 2D            
HSQC    
HSQC-TOCSY      
HMBC    
ADEQUATE        
EXSIDE        
FAST HMQC (ASAP method)    
             
X-X or X-PROTON 2D            
15N-1H HMBC          
15N-1H HSQC /w H2O supression          
31P-1H HMQC        
29Si-1H HMQC        
31P-31P COSY          
19F-13C HMQC





             
X-NUCLEI 1D            
13C  
13C /W 19F Decoupling          
2H  
2H T1 measurement          
7Li      
11B        
14N            
15N        
17O          
19F      
23Na          
27Al          
29Si      
31P  
33S          
39K          
77Se      
113Cd      
119Sn          
125Te        
183W          
195Pt          
199Hg          
207Pb          
             
Solid State NMR            
13C experiements        
31P and 29Si          

Descriptions of NMR Techniques for Structural Determination

The following techniques are implemented. Not all are implemented on all NMRs. In paranthesis, is the optimal NMR for that particular experiment. They are grouped by the type of information provided. Others are available upon request.

H-H connectivity -through J coupling

J measurement (H-H)

H-H spatial proximity

  • NOESY-2D /w ZQ suppression (400L, 400SL, 500, 500 Ascend)
  • ROESY-2D (400L. 400SL, 500, 500 Ascned)
  • 1D-gradient selectived NOESY (400L, 400SL, 500, 500 Ascend)
  • HSQC-ROESY
  • "easy" ROESY (for tocsy suppression) (500, 500 Ascend)

Carbon-proton connectivity - through J coupling

  • HSQC or HMQC direct correlation - one bond (400L, 400SL, 500, 500 Asc)
  • ASAP HMQC - 40 second low resolution HMQC (400L, 400SL, 500 Asc)
  • HSQC-TOCSY - carbon resolved TOCSY (400SL, 500, 500 Asc)
  • HMBC - long range correlation - 2 to 3 bond. Accordion method for reduced dependence on coupling values (400L, 400SL. 500, 500asc)
  • H2BC - Heteronuclear two bond correlation
  • ADEQUATE - proton detected INADEQUATE- long range correlation

J measurement (C-H long range)

Water suppression

  • PURGE (400L, 400SL, 500, 500asc)
  • presaturation (400L, 400SL, 500, 500asc)

Exchange - Relaxation

Heteronuclear NMR

  • Fluorine (300nb, 400SL, 500)
  • carbon, phosphorus, deuterium, nitrogen, etc... (300wb, 400SL, 500)
  • DEPT (300wb, 400SL)

Diffusion

  • diffusion measurements, size determination (500, 500asc)

Solid-State-NMR

  • CP-MAS (400SL)