Table 2. GS and ES Properties of Fe(III) Complexes Used in CT State-Driven Photoredox Catalysis, in Comparison with a Traditional Ir(III)-PCc.
| Complex | [Fe(III)(btz)3](PF6)3 (11) | [Fe(III)(phtmeimb)2]PF6 (12) | [Ir(III)(dF(CF3)ppy)2(dtbpy)]PF6 (3)a |
|---|---|---|---|
| Type of ES | LMCT | LMCT | MLCT |
| λabs [nm] | 558 | 502 | 380 |
| εmax [103 · M−1 cm−1] | 1.2 | 3.0 | 6.2 |
| λem [nm] | 600 | 655 | 470 |
| τ [ns] | 0.10 | 1.96 | 2300 |
| Φ [%] | 0.03 | 2.1 | 68 |
| E1/2(M(IV)/M(III)) [V vs Fc+/0] | 1.2 | 0.25 | 1.38 |
| E1/2(M(III)/M(II)) [V vs Fc+/0] | –0.58 | –1.16 | –1.68b |
| E°(M(IV)/*M(III)) [V vs Fc+/0] | –1.0 | –1.88 | –1.20 |
| E°(*M(III)/M(II)) [V vs Fc+/0] | 1.60 | 1.0 | 0.90 |
| Ref | (82) | (83) | (23) |
a
The redox potentials for [Ir(III)(dF(CF3)ppy)2(dtbpy)]PF6 (3) were converted from V vs saturated calomel electrode (SCE) to V vs Fc+/0 using the value for Fc+/0 vs SCE of +0.31 V cited in the original paper.23
b
Value for E1/2(L/L–).
c
All redox potentials are given vs ferrocenium/ferrocene (Fc+/0) in acetonitrile.46 Values for [Fe(btz)3](PF6)3 (11) and [Fe(phtmeimb)2]PF6 (12) were obtained in air-saturated acetonitrile at room temperature.