Table 1. Polarization Enhancement (ε) Values for Three Aromatic Proton Sites of Pyridine Observed with Different Catalysts in Aqueous and Nonaqueous Environmentsa.
| catalyst | solvent | ε (Ho) | ε (Hp) | ε (Hm) |
|---|---|---|---|---|
| 7 | 100% d6-ethanol | –42 | –57 | –11 |
| 7 | 100% d6-ethanol | –45 | –61 | –11 |
| 7 | 13% D2O/87% d6-ethanol | –37 | –27 | –12 |
| 7 | 13% D2O/87% d6-ethanol | –38 | –31 | –14 |
| 7 | 43% D2O/57% d6-ethanol | –9.5 | –5.7 | –1.3 |
| 7 | 43% D2O/57% d6-ethanol | –7.3 | –4.9 | –0.4 |
| 7 | 63% D2O/37% d6-ethanol | ∼0 | ∼0 | ∼0 |
| 13 | 100% D2O | –25 | –19 | –11 |
| 13 | 100% D2O | –32 | –25 | –16 |
| 16 | 100% D2O | ∼0 | ∼0 | ∼0 |
a
Reported ε values are calculated from spectral integrals and are approximate, with estimated uncertainties of ∼10%. Results from the top two acquisitions for each condition are reported.