Singlet-state exchange NMR spectroscopy for the study of very slow dynamic processes

摘要

A nuclear magnetic resonance (NMR) method for singlet-state exchange NMR-Spectroscopy comprises the following steps:a. excitation of single-quantum in-phase coherences,b. generation of single-quantum anti-phase coherences,c. excitation of zero-quantum coherences ZQ_x and/or longitudinal two-spin order 2I_zS_z (="ZZ order") using a π/4 pulse,d. reversal of the sign of the zero-quantum coherences ZQ_x under the effect of the difference of the chemical shifts of the examined spins,e. transformation of the zero-quantum coherences ZQ_x and/or longitudinal two-spin ZZ order into singlet-state populations by means of RF irradiation during a mixing period τ_m,f. reconversion of the singlet-state populations remaining at the end of the mixing period τ_m into zero-quantum coherences ZQ_x and/or ZZ order,g. reversal of the sign of the zero-quantum coherences ZQ_x under the effect of the difference of the chemical shifts of the examined spins,h. reconversion of zero-quantum coherences ZQ_x and/or ZZ order into single-quantum anti-phase coherences.i.;With the inventive broadband method for the excitation of single state population correlations between states that are connected through very slow processes can be monitored by NMR