Premium
Relative signs of 29 Si 13 C couplings
Author(s) -
Blechta Vratislav,
Schraml Jan
Publication year - 2008
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.2241
Subject(s) - homonuclear molecule , chemistry , trimethylsilane , coupling constant , isotope , coherence (philosophical gambling strategy) , pulse sequence , coupling (piping) , analytical chemistry (journal) , nuclear magnetic resonance , molecule , physics , medicinal chemistry , organic chemistry , nuclear physics , mechanical engineering , particle physics , quantum mechanics , engineering
Abstract Two pulse sequences applicable to the determination of relative signs of coupling constants, gHSQC‐RELAY(P) and gHSQC‐RELAY(D), were developed and tested. These sequences are suitable for determination of relative signs of long‐range coupling constants (<2 Hz) between two heteronuclei of low abundance (such as 29 Si and 13 C), and are applicable even to cases in which one of the heteronuclei ( 29 Si) does not exhibit coupling with some of the detected protons ( 1 H). The two sequences differ in the manner in which they suppress undesirable homonuclear coherence transfers. Each of the sequences can be combined with an isotope filter for better suppression of the centerlines arising from more abundant NMR‐inactive isotopes. The sequences were tested on ethoxytrimethylsilane and (E)‐(buta‐1,3‐dienyloxy)trimethylsilane, and we conclude that 2 J ( 29 Si‐O‐ 13 C) is positive while 3 J ( 29 Si‐O‐C‐ 13 C) is negative in both compounds. Copyright © 2008 John Wiley & Sons, Ltd.