Separation of cross-relaxation and exchange in two-site spin systems with weak spin-spin couplings

A ratio relating the cross-relaxation rates, rate constants, and cross-peak and diagonal peak integrals is used for the analysis of exchanging two-site spin systems with weak scalar spin-spin couplings to extract the rate constants and cross-relaxation rates contributing to the same cross-peaks in two-dimensional nuclear Overhauser enhancement spectra (2-D NOESY). The method to separate contributions from cross-relaxation and chemical exchange into the cross-peaks in NOESY spectra was applied to investigate the intramolecular dynamics of trisulfide 4H, 8H-naphtho[1,8-ef]1,2,3-trithiocine in solutions.