title: On the interference of J(HH) modulation in HSQMBC-IPAP and HMBC-IPAP experiments.
abstract: The effects of phase modulation due to homonuclear proton-proton coupling constants in HSQMBC-IPAP and HMBC-IPAP experiments are experimentally evaluated. We show that accurate values of small proton-carbon coupling constants, (n)J(CH), can be extracted even for phase-distorted cross-peaks obtained from a selHSQMBC experiment applied simultaneously on two mutually J-coupled protons. On the other hand, an assessment of the reliability of (n)J(CH) measurement from distorted cross-peaks obtained in broadband IPAP versions of equivalent HMBC and HSQMBC experiments is also presented. Finally, we show that HMBC-COSY experiments could be an excellent complement to HMBC for the measurement of small (n)J(CH) values.
authors.affiliation: Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, E-08193, Bellaterra, Catalonia, Spain.
authors.forename: Josep
authors.initials: J
authors.lastname: Saurí
authors.forename: Teodor
authors.initials: T
authors.lastname: Parella
mesh_terms: D009682:Magnetic Resonance Spectroscopy / Q000592:standards; D011522:Protons; D012015:Reference Standards
chemical_list: D011522:Protons
keywords: HMBC; HSQMBC; IPAP; proton-carbon coupling constants; selHSQMBC