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

Abstract

Four new [FeFe]-hydrogenase-mimic-containing CPs and a supramolecule, {(CO) 6 [Fe 2 S 2 −Ag](2-cpmt) 2 (SbF 6 )•0.5(CH 2 Cl 2 )} n (1), {(CO) 6 [Fe 2 S 2 −Ag](2-cpmt) 2 (ClO 4 )} n (2), {(CO) 6 [Fe 2 S 2 ](2-cpmt) 2 Ag(pxylene)(CF 3 SO 3 )} n (3), and {(CO) 5 (PPh 3 )[Fe 2 S 2 −Ag](2-cpmt) 2 (ClO 4 )•1.5-(toluene)} n (4), were obtained from two new chelating ligands [FeFe](2cpmt) 2 (CO) 6 (L1) and [FeFe](2-cpmt) 2 (CO) 5 (PPh 3 ) (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 μ 2 -S atoms, and the C C�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 H 2 generation experiments indicated that L2 has greatly improved catalytic performance over L1 due to the PPh 3 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 H 2 production performance of heterogeneous [FeFe]-hydrogenase catalysts.