Accordion BIRD-HMBC experiments: improved one-bond correlation suppression in accordion heteronuclear multiple-bond correlation-type experiments

✍ Scribed by Julien Furrer

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 291 KB
• Volume: 44
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1857

✦ Synopsis

Abstract

Modifications of the BIRD‐HMBC experiment, in which the accordion principle and a constant time period have been introduced, are presented. With the simple accordion BIRD‐HMBC, the use of a BIRD^r, X^ element in the middle of the variable long‐range couplings evolution period efficiently eliminates unwanted ^1^J~CH~ signals and samples a broad range of long‐range heteronuclear couplings. While the accordion BIRD‐HMBC experiment shows reduced F~1~ modulation, superior suppression of unwanted ^1^J~CH~ signals and sensitivity comparable to the ACCORD‐HMBC, the addition of another constant time period suppresses F~1~ modulation due to ^1^H‐^1^H coupling, while preserving the excellent suppression of unwanted ^1^J~CH~ signals. The constant‐time (CT) accordion BIRD‐HMBC experiment combines sensitivity similar to the CIGAR‐HMBC and superior suppression of unwanted ^1^J~CH~ signals. Results of identically optimized ACCORD‐HMBC, accordion BIRD‐HMBC, CT accordion BIRD‐HMBC and CIGAR‐HMBC experiments performed on a sample of strychnine are compared and discussed. Copyright © 2006 John Wiley & Sons, Ltd.