Constant time inverse-detection gradient accordion rescaled heteronuclear multiple bond correlation spectroscopy: CIGAR-HMBC

Abstract

A further refinement of the recently reported IMPEACH-MBC long-range heteronuclear shift correlation experiment is described. The new experiment, CIGAR-HMBC (constant time inverse-detected gradient accordion rescaled long-range heteronuclear multiple bond correlation), modifies the constant time variable delay of the IMPEACH-MBC experiment to allow user-determined scaling of F1 modulation. The refinement offered in the CIGAR-HMBC experiment allows the investigator to reintroduce whatever degree of F1 modulation is desired to authenticate weak long-range responses. Results obtained with the CIGAR-HMBC experiment using a range of values for Jscale are compared with results obtained with identically optimized ACCORD-HMBC and IMPEACH-MBC experiments. Copyright © 2000 John Wiley & Sons, Ltd.