title: Accurate measurements of small J coupling constants under inhomogeneous fields via intermolecular multiple-quantum coherences.
abstract: Two new NMR pulse sequences, based on intermolecular multiple-quantum coherences (iMQCs), were developed to obtain apparent J coupling constants with a scaling factor from one to infinity relative to the conventional J coupling constants. Here the apparent J coupling constants were defined as apparent peak separations in unit of Hz in a reconstructed spectrum for a coupled spin system. Except for the adjustable scaling factor for apparent J coupling constants, the sequences hold the advantage of high acquisition efficiency, and retain the spectral information such as chemical shifts, multiplet patterns, and relative peak areas under inhomogeneous fields. For spin systems with small scalar coupling constants, well-resolved J-spectra can be achieved by selecting a proper scaling factor. Theoretical predictions are in good agreement with simulation results and experimental observations.
authors: Department of Physics, State Key Laboratory for Physical Chemistry of Solid Surface, Xiamen University, Xiamen, Fujian, PR China.
authors: Yanqin
authors: Y
authors: Lin
authors: Zhong
authors: Z
authors: Chen
authors: Shuhui
authors: S
authors: Cai
authors: Jianhui
authors: J
authors: Zhong
mesh_terms: D000465:Algorithms; D002074:Butanones / Q000737:chemistry; D003510:Cyclohexanes / Q000737:chemistry; D006639:Histidine / Q000737:chemistry; D008968:Molecular Conformation; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*
chemical_list: D002074:Butanones; D003510:Cyclohexanes; C506365:Cyclohexane; D006639:Histidine; C005222:methylethyl ketone