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Improved performance accordion heteronuclear multiple-bond correlation spectroscopy-IMPEACH-MBC
C E Hadden1, G E Martin, V V Krishnamurthy
1Pharmaceutical Development, Pharmacia & Upjohn, Kalamazoo, Michigan 49001-0199, USA.
Journal of Magnetic Resonance (San Diego, Calif. : 1997)
|September 10, 1999
Summary
The IMPEACH-MBC experiment improves upon ACCORD-HMBC by suppressing proton-proton coupling modulation, enhancing long-range heteronuclear shift correlation for clearer results in NMR spectroscopy.
Area of Science:
- Nuclear Magnetic Resonance (NMR) Spectroscopy
- Organic Chemistry
- Analytical Chemistry
Background:
- The ACCORD-HMBC experiment enables long-range heteronuclear shift correlation.
- Proton-proton coupling can modulate signal responses, complicating data interpretation.
Purpose of the Study:
- To introduce IMPEACH-MBC, a modified ACCORD-HMBC experiment.
- To suppress proton-proton coupling modulation in HMBC experiments.
Main Methods:
- Development of the IMPEACH-MBC pulse sequence.
- Incorporation of a constant time variable delay.
- Comparison of IMPEACH-MBC and ACCORD-HMBC on a strychnine sample.
Main Results:
- IMPEACH-MBC effectively suppresses (1)H-(1)H coupling modulation.
- This suppression eliminates F(1) modulation or 'skew' in the second frequency domain.
- Identically optimized experiments showed distinct differences in data quality.
Conclusions:
- IMPEACH-MBC offers improved performance over ACCORD-HMBC.
- The new experiment provides cleaner NMR data for structural elucidation.
- This advancement benefits the analysis of complex organic molecules.