Improved pulse sequences for measurement of small long‐range couplings between heteronuclei (29Si?13C) at natural abundance |
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| Authors: | Vratislav Blechta Jan Schraml |
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| Affiliation: | Institute of Chemical Process Fundamentals of the ASCR, v. v. i., Rozvojová 135, CZ‐165 02 Prague 6 ‐ Suchdol, Czech Republic |
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| Abstract: | The gradient pulse sequences for measurement of small long‐range couplings between heteronuclei (29Si? 13C) in natural abundance reported to date (INEPT‐(Si,C)gCOSY and INEPT‐(Si,C,Si)HMQC) suffer from significant signal loss when these nuclei (29Si, 13C) are coupled through one‐bond couplings to protons. This negative effect can be completely eliminated by using non‐gradient versions (INEPT‐(Si,C)COSY) or by switching proton decoupling off during gradient pulses (modified INEPT‐(Si,C,Si)gHMQC pulse sequence). The beneficial effects of these two approaches on the quality of the spectra are demonstrated here. Copyright © 2009 John Wiley & Sons, Ltd. |
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| Keywords: | NMR 1H NMR 13C NMR 29Si NMR silylated compounds long‐range Si,C coupling INEPT‐(Si,C)gCOSY INEPT‐(Si,C,Si)gHMQC |
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