Abstract:
Two new mimetics ofFeFe hydrogenase, 1 and 2, were synthesized using Fe(CO)
5 and a thiol-containing ligand in a multi-step reaction. A three-component homogeneous photocatalytic system was then constructed using complexes 1 or 2 as the photocatalyst, erythrosin B sodium salt (EBS-
2-) as the photosensitizer, and triethylamine (TEA) as the electron donor & proton source for hydrogen production. Under optimal conditions of CH
3CN/H
2O solution volume ratio of 1:1, the pH value of 12, and visible light (
λ>420 nm) irradiation for 4 h, the maximum hydrogen production was 205.0
μmol. The turn over number (TON) for compound 2 in catalytic conversion is 51.4. The results show that the ligands contain more proton capture sites, which is conducive to the formation of the hydrogen-producing active intermediate H
2-2Fe2S (η
2-H
2-Fe
ⅡFe
Ⅰ) species, further improving the hydrogen production activity of the catalyst. The initial transfer of the photogenerated electron from
1*EBS
2- to complexes 1 and 2 is thermodynamically favorable, whereas the subsequent transfer of the second electron to these catalysts is thermodynamically unfavorable.