[Fe₂S₂]-Hydrogenase-Mimic-Containing Supramolecule and Coordination Polymers: Syntheses, H₂ Evolution Properties, and Their Structure–Function Relationship Study

Four new [FeFe]-hydrogenase-mimic-containing CPs and a supramolecule, {(CO)6[Fe2S2–Ag](2-cpmt)2(SbF6)·0.5(CH2Cl2)}n (1), {(CO)6[Fe2S2–Ag](2-cpmt)2 (ClO4)}n (2), {(CO)6[Fe2S2](2-cpmt)2Ag(p-xylene)(CF3SO3)}n (3), and {(CO)5(PPh3)[Fe2S2–Ag](2-cpmt)2(ClO4)·1.5(toluene)}n (4), were obtained from two new chelating ligands [FeFe](2-cpmt)2(CO)6 (L1) and [FeFe](2-cpmt)2(CO)5(PPh3) (L2) by direct synthesis. All new compounds are characterized by single-crystal X-ray diffraction, FTIR, solid-state UV–vis spectra, and CV. It was noteworthy that L1 and L2 serve as multidentate ligands with two terminal −CN groups, the μ2-S atoms, and the CC≡O as coordination sites, and the coordination modes between Ag+ and multidentate chelating ligands are completely different from each other in four complexes. The results of photochemical H2 generation experiments indicated that L2 has greatly improved catalytic performance over L1 due to the PPh3 substituent. The amount of hydrogen produced from four Ag complexes 1–4 is different due to the coordination environment difference around catalytic active sites. This work enriched the coordination chemistry of [FeFe]-hydrogenase mimics and improved the H2 production performance of heterogeneous [FeFe]-hydrogenase catalysts.