Table 2.
Summary of the distance-dependence of catalyst-promoted 4’-hydrogen abstraction.
| complex | Rrxn (Å)a |
|---|---|
| Fe-DOTA-Rev | 2 ± 1 |
| Fe-DTPA-Rev | 5 ± 1 |
| Co-DTPA-Rev | < 5 |
| Ni-DTPA-Rev | < 6 |
| Cu-DTPA-Rev | < 6 |
| Fe-EDTA-Rev | 6 ± 1 |
| Co-EDTA-Rev | 3 ± 1 |
| Ni-EDTA-Rev | 7 ± 1 |
| Cu-EDTA-Rev | 6 ± 1 |
| Cu-KGHK-Rev | 5 ± 1 |
| Fe-NTA-Rev | 5 ± 1 |
| Co-NTA-Rev | 4 ± 1 |
| Cu-NTA-Rev | 6 ± 1 |
a
Radius obtained by fitting to a Gaussian distribution; the apparent rates of 4’-H abstraction within this radius accounted for ~70% of the total apparent rate of 4’-H abstraction for each M-chelate-Rev catalyst. A larger radius is attributed to either a metal-dissociated ROS as the reactive intermediate or greater flexibility of the linker between the metal center and Rev. The reactions contained both H2O2 and ascorbate (1 mM each).