Measurement of the sign and the magnitude of heteronuclear coupling constants from spin-state-edited J-cross-polarization NMR experiments.
New spin-state-selective (S3) NMR pulse sequences exclusively applying cross-polarization schemes to achieve optimum homonuclear and heteronuclear 1H-X coherence transfer are reported for the simple and accurate measurement of the magnitude and sign of heteronuclear coupling constants for samples at natural abundance. The proposed spin-edited HCP-TOCSY experiments are based on clean heteronuclear S3 excitation, generated by simultaneous co-addition of two independent in-phase and anti-phase components created during the mixing heteronuclear J-cross-polarization (HCP) step, which is finally transferred to other protons by a conventional homonuclear TOCSY mechanism. Selective 1D and non-selective 2D approaches for the easy determination of long-range proton-carbon and proton-nitrogen coupling constants on any protonated and non-protonated heteronuclei are presented and discussed for several organic molecules.
Parella
Teodor
T
Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona, Spain. teo@rmn3.uab.es
Belloc
Jordi
J
Sánchez-Ferrando
Francesc
F
D002244:Carbon / Q000737:chemistry; D003627:Data Interpretation, Statistical; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008610:Menthol / Q000737:chemistry; D008968:Molecular Conformation; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D011522:Protons; D011799:Quinazolines / Q000737:chemistry; D012680:Sensitivity and Specificity; D013113:Spin Labels; D014230:Triazoles / Q000737:chemistry
D011522:Protons; D011799:Quinazolines; D013113:Spin Labels; D014230:Triazoles; D008610:Menthol; D002244:Carbon; C112424:albaconazole