Table 3. GS and ES Properties of Fe(II) Complexes Used in CT State-Driven Photoredox Processes, and a Comparison with a Traditional Ru(II)-PCf.
| Complex | [Fe(II)(btz)3](PF6)2 (14) | [Fe(II)(phenN,N’^C)2] (13) | [Ru(II)(bpy)3]Cl2 (1) |
|---|---|---|---|
| Type of ES | MLCT | MLCT | MLCT |
| λabs [nm] | 730 | 765 | 452 |
| εmax [103 · M−1 cm−1] | 1.22 | –a | 14.6 |
| λem [nm] | –a | 1220 | 625 |
| τ [ns] | 0.528 | 0.8b | 180 | 930c |
| Φ [%] | –a | –a | 1.8 | 9.5c |
| E1/2(M(III)/M(II)) [V vs Fc+/0] | –0.58 | 0.88 | 0.92 |
| E1/2(L/L–) [V vs Fc+/0] | –2.38 | –2.46 | –1.69d |
| E°(M(III)/*M(II)) [V vs Fc+/0] | –1.6 | –2.0 | –1.20 |
| E°(*L/L–) [V vs Fc+/0] | –1.4e | –1.36 | 0.34 |
| Ref | (95) | (96) | (42,97,98) |
a
Not determined in the paper.
b
Measured in benzene.
c
Measured in air-saturated and oxygen-free acetonitrile solution, respectively.
d
Measured in methanol.
e
Irreversible reduction.
f
All redox potentials are given vs Fc+/0 in acetonitrile.46