title: Improved performance accordion heteronuclear multiple-bond correlation spectroscopy-IMPEACH-MBC.
abstract: A modification of the recently reported ACCORD-HMBC long-range heteronuclear shift correlation experiment is described. The new experiment, IMPEACH-MBC (improved performance accordion heteronuclear multiple-bond correlation), introduces a new pulse sequence element, a constant time variable delay. The incorporation of the constant time variable delay into the IMPEACH-MBC sequence suppresses (1)H-(1)H coupling modulation inherent to the utilization of the accordion principle to sample a broad range of potential long-range heteronuclear couplings. (1)H-(1)H coupling modulation, which introduces an F(1) modulation or a "skew" of responses in the second frequency domain of the ACCORD-HMBC experiment, is suppressed in the IMPEACH-MBC experiment. Results of identically optimized IMPEACH-MBC and ACCORD-HMBC experiments performed on a sample of strychnine are compared.
authors.affiliation: Pharmaceutical Development, Pharmacia & Upjohn, Kalamazoo, Michigan 49001-0199, USA.
authors.forename: C E
authors.initials: CE
authors.lastname: Hadden
authors.forename: G E
authors.initials: GE
authors.lastname: Martin
authors.forename: V V
authors.initials: VV
authors.lastname: Krishnamurthy
mesh_terms: D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D015394:Molecular Structure; D013331:Strychnine / Q000737:chemistry*
chemical_list: D013331:Strychnine