IPAP-HSQMBC: measurement of long-range heteronuclear coupling constants from spin-state selective multiplets.
A new NMR approach is proposed for the measurement of long-range heteronuclear coupling constants ((n)J(XH), n>1) in natural abundance molecules. Two complementary in-phase (IP) and anti-phase (AP) data are separately recorded from a modified HSQMBC experiment and then added/subtracted to provide spin-state-selective α/β-HSQMBC spectra. The magnitude of (n)J(XH) can be directly determined by simple analysis of the relative displacement between α- and β-cross-peaks. The robustness of this IPAP-HSQMBC experiment is evaluated experimentally and by simulation using a variety of different conditions. Important aspects such as signal intensity dependence and presence of unwanted cross-talk effects are discussed and examples on the measurement of small proton-carbon ((n)J(CH)) and proton-nitrogen ((n)J(NH)) coupling constants are provided.
Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, E-08193-Bellaterra, Barcelona, Spain.
Sergi
S
Gil
Juan Félix
JF
Espinosa
Teodor
T
Parella
D000465:Algorithms; D002110:Caffeine / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D016572:Cyclosporine / Q000737:chemistry; D004574:Electromagnetic Fields; D004578:Electron Spin Resonance Spectroscopy; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009584:Nitrogen / Q000737:chemistry; D011522:Protons; D013331:Strychnine / Q000737:chemistry
D011522:Protons; D002110:Caffeine; D002244:Carbon; D016572:Cyclosporine; D013331:Strychnine; D009584:Nitrogen