title: Homonuclear long-range correlation spectra from HMBC experiments by covariance processing.
abstract: We present a new application of covariance nuclear magnetic resonance processing based on 1H--13C-HMBC experiments which provides an effective way for establishing indirect 1H--1H and 13C--13C nuclear spin connectivity at natural isotope abundance. The method, which identifies correlated spin networks in terms of covariance between one-dimensional traces from a single decoupled HMBC experiment, derives 13C--13C as well as 1H--1H spin connectivity maps from the two-dimensional frequency domain heteronuclear long-range correlation data matrix. The potential and limitations of this novel covariance NMR application are demonstrated on two compounds: eugenyl-beta-D-glucopyranoside and an emodin-derivative.
authors.affiliation: Johannes Kepler University Linz, Altenbergerstrasse 69, 4040 Linz, Austria.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schoefberger
authors.forename: Vilko
authors.initials: V
authors.lastname: Smrecki
authors.forename: Drazen
authors.initials: D
authors.lastname: Vikić-Topić
authors.forename: Norbert
authors.initials: N
authors.lastname: Müller