Spins that chemically exchange into state B during this period will receive an additional phase shift, resulting in fanning out of their magnetisation vectors. By following these spins through the rest of the sequence, it may thus be observed that spin B magnetization can be generated, with a phase shift, from the initial spin A magnetization. The extent of this exchange-mediated coherence transfer from state A to state B depends on the frequency difference between the states and the transfer time, τ INEPT = 1/2J, relative to the chemical exchange rate. Exact numerical calculations (Fig. ) show that when both the scalar coupling and frequency difference are comparable to the exchange rate (center of diagrams), a non-trivial population of B magnetization is generated with a phase shift dependant on the frequency difference, as predicted from our schematic argument above (Fig. ). To explore the above analysis experimentally, natural abundance 1 H, C HSQC and HMQC spectra were acquired of DMTCA at 298 K and 16.44 T (Fig. ). Under these conditions, k ex τ INEPT = 0.45 and k ex /∆ωH = 0.11 (marked by an asterisk in Fig. ), which is a favourable regime to observe the predicted coherence transfer effects. Again, unexpected exchange-induced cross-peaks were observed in both experiments, with a particularly complex phase structure in the case of the HMQC experiment (Fig. ). This may be rationalised since in the HSQC experiment zz filters suppress phase distortions from the first INEPT transfer and some phase distortions arising from exchange during t 1 . In contrast, in the HMQC experiment all parts of the pulse sequence contribute to the phase of the observed magnetisation, resulting in remarkably complex lineshapes. HMQC spectra acquired at multiple fields to probe the effect of varying ∆ω clearly show that larger frequency differences are associated with larger phase distortions (Fig. ), as predicted from Fig. , while applying XY16 CPMG pulse trains during HMQC coherence transfer periods suppresses the build-up of phase shifts, greatly simplifying the structure of the exchange cross-peaks (Fig. ). Again, high quality fits and measurement of the exchange rate could be obtained by 2D lineshape analysis (Fig. ). We note that coherence transfers via the three-bond scalar coupling 3 J CH (not resolved, but estimated to be ca. Finally, to illustrate a potential application of these analyses, we examined the temperature dependence of exchange within DMTCA using a series of NOESY and HMQC experiments (Fig. and). The HMQC experiment was selected as this was established above to be the most sensitive experiment for observing phase distortions. Exchange rates were determined from 2D fitting of individual spectra, and varied from 19.0 ± 0.6 s -1 at 278 K to 482 ± 4 s -1 at 313 K. NOESY and HMQC results both fitted well to the Eyring equation (Fig. ), fully consistent with previous measurements (∆H ‡ = 67.4 ± 3.9 kJ mol -1 and ∆S ‡ = 15 ± 13 kJ mol -1 K -1 ). We note that at higher temperatures, 2D lineshape analysis of the NOESY experiments, acquired with very short mixing times, was also required in order to characterise the exchange process (Fig. ).