[Fe2S2–Agx]-Hydrogenase Active-Site-Containing Coordination Polymers and Their Photocatalytic H2 Evolution Reaction Properties

Three [Fe2S2-Agx]-hydrogenase active-site-containing coordination polymers (CPs), {[Fe2S2-Ag1](4-cpmt)2(CO)6(ClO4-)}n (1), {[Fe2S2-Ag2](4-cpmt)2(CO)6(OTf-)2(benzene)}n (2), and {[Fe2S2-Ag2](3-cpmt)2(CO)6(ClO4-)2}n (3), were obtained by a direct synthesis method from ligands [FeFe](4-cpmt)2(CO)6 [L1; 4-cpmt = (4-cyanophenyl)methanethiolate] and [FeFe](3-cpmt)2(CO)6 [L2; 3-cpmt = (3-cyanophenyl)methanethiolate] with silver salts. 1-3 represent the first examples of [FeFe]-hydrogenase-based CPs. It was worth noting that the Ag-S bonding between the Ag centers and S atoms of a [Fe2S2] cluster produced a novel [Fe2S2-Agx] (x = 1 or 2) catalytic site in all three polymers. The results of photochemical H2 generation experiments indicated that 2 and 3 containing [Fe2S2-Ag2] active sites showed obviously improved catalytic performances compared with ligands L1 and L2 and [Fe2S2-Ag1]-containing 1. This work provides a pioneering strategy for the direct synthesis of [Fe2S2]-based CPs or metal-organic frameworks.