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Experiments to Detect Long-Range Heteronuclear Shift Correlations: LR-J-HSMQC

✍ Scribed by A.M. Torres; W.A. Bubb; P.W. Kuchel

Publisher: Elsevier Science
Year: 2002
Tongue: English
Weight: 272 KB
Volume: 156
Category: Article
ISSN: 1090-7807
DOI: 10.1006/jmre.2002.2563

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✦ Synopsis

The utility of the J-HSMQC experiment to detect long-range CH correlations was investigated. Two new long-range J-compensated pulse sequences, LR-J-HSMQC(80,27) and LR-J-HSMQC(27,80), were developed using the (3beta(x))beta(y) composite 90 degrees pulse sequence. These two experiments were shown to be effective for long-range coupling constants, (n)J(CH), that were greater than 3 Hz. Although the overall sensitivities of the long-range J-HSMQC experiments were slightly lower than that of the conventional decoupled HMBC experiment, their 2D maps showed additional cross peaks that could be useful in structure elucidation. LR-J-HSMQC(27,80) was very efficient in yielding two- and four-bond relay correlations. The utility of the new sequences is demonstrated with strychnine as the sample.

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