Table 3. Reduction Potentials of Free Bis(imino)pyridine Ligands and Reduction Potentials and Infrared Stretching Frequencies of the N2 Band in (PDI)CoN2 Compounds.
| reduction potentialsa |
IR νNNb | ||
|---|---|---|---|
| compound | free ligand | (PDI)CoN2 | (PDI)CoN2 |
| (iPrPDI)CoN2 (1) | –2.62c | –0.97 | 2101 |
| (TricPDI)CoN2 (2) | –2.67 | –d | 2106 |
| (MePDI)CoN2 (4) | –2.71c | –0.93 | 2105 |
| (iPrEtPDI)CoN2 (5) | –2.65 | –0.87 | 2100 |
| 4-pyrr-(iPrPDI)CoN2 (7) | –2.82c,e | –1.08 | 2091 |
a
All reductions potentials are reported in V vs Fc/Fc+.
b
All IR spectra were recorded in pentane and are reported in cm–1.
c
Value from ref (72).
d
Not observed.
e
The value is for 4-NMe2-(iPrPDI).