Comparing h2bc and 1,1-adequate

  • Summary

NM160003E

Both h2bc and 1,1-adequate are designed to separate 2JCH and 3JCH when a combination of cosy and hmbc is unable to identify correlation signals. Features and best applications of these two techniques, which are used for the same objective, are described below.

4-methylumbelliferone
4-methylumbelliferone
h2bc can only acquire limited correlation signals from 4-methylumbelliferone rich in quarternary carbon shown in the figure. 1,1-adequate can detect more correlation signals although the process takes time. Also, because the fatty series and aromatic ring have different 1JCC values, setting measuring conditions using either value will change the levels of sensitivity of the correlation signals detected.
【h2bc】
  • Correlation of 2JCH only observed
  • Higher sensitivity than 1,1-adequate
  • No correlation with quarternary carbon observed
  • Good result acquired under default conditions
     
【1,1-adequate】
  • Correlation of both 1JCH and 2JCH observed
  • Lower sensitivity than h2bc
  • Correlation with quarternary carbon observed as well
  • Correlation signal may not be visible under certain conditions (1JCC value)

h2bc, 4 scans (25 min)

1,1-adequate, 48 scans (7h)
Instrument:JNM-ECZ400S+ROYAL probe; sample:100 mg 4-methylumbelliferone 

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