title: Development of a method for the measurement of long-range 13C-1H coupling constants from HMBC spectra.
abstract: This paper describes a number of improvements to a method, developed in this laboratory and described in J. Magn. Reson. 85 (1989) 111-113, which makes it possible to determine values of long-range 13C-1H coupling constants from heteronuclear multiple bond correlation (HMBC) spectra. First, it is shown how pulsed-field gradients can be introduced into the HMBC experiment without perturbing the form of the cross-peak multiplets; a one-dimensional version of the experiment is also described which permits the rapid measurement of a small number of couplings. Second, the experiment is modified so that one-bond and long-range cross-peaks can be separated, and so that the one-bond cross-peaks have more reliable intensities. Finally, it is shown how these one-bond cross-peaks can be used to advantage in the fitting procedure.
authors.affiliation: University of Cambridge, Department of Chemistry, Lensfield Rd, Cambridge, CB2 1EW, UK.
authors.forename: Richard A E
authors.initials: RA
authors.lastname: Edden
authors.forename: James
authors.initials: J
authors.lastname: Keeler
mesh_terms: D000465:Algorithms; D002247:Carbon Isotopes / Q000737:chemistry*; D005240:Feasibility Studies; D006859:Hydrogen / Q000737:chemistry*; D006860:Hydrogen Bonding; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D013113:Spin Labels; D013331:Strychnine / Q000737:chemistry*
chemical_list: D002247:Carbon Isotopes; D013113:Spin Labels; D006859:Hydrogen; D013331:Strychnine